JP6161704B2 - Imaging apparatus, vehicle, and image correction method - Google Patents

Description

  The present invention relates to an imaging device, a vehicle, and an image correction method.

  The stereo camera includes a plurality of cameras. Each camera is installed in a predetermined posture at a predetermined position. Each camera performs shooting by stereo vision. An image obtained from each camera is processed by an image processing unit. For example, the image processing unit calculates information in the depth direction of the image using the internal parameters and the external parameters of the camera. Camera external parameters are defined by the position and orientation of the camera.

  Here, the deviation of the position and orientation of the camera is appropriately referred to as “positional deviation”. Misalignment occurs due to various causes. For example, when the camera receives an impact or vibration, a positional shift may occur. When the “positional deviation” occurs, the actual position and the actual posture of the camera deviate from the position and the posture defined by the external parameters. As a result, the error included in the information in the depth direction increases, and the accuracy of the information in the depth direction decreases.

  In order to eliminate the positional deviation, the operator of the stereo camera may manually adjust the position and orientation of the camera. According to this method, the camera can be returned to the correct position and the correct posture. However, it takes time for the operator.

  Therefore, conventionally, a method for canceling the positional deviation by correcting the image has been studied. This technique is as follows, for example. First, the camera captures a test pattern such as a grid chart. The image processing unit adjusts correction parameters for correcting the image based on the obtained image. Specifically, the image processing unit adjusts correction parameters for translating the image in the vertical direction and correction parameters for rotating the image. The image processing unit corrects the image using the adjusted correction parameter (see, for example, Patent Documents 1 and 2). In this method, it is not necessary to adjust the position and orientation of the camera, so that the burden on the operator can be reduced.

JP 2004-132870 A JP 2000-284389 A

However, the conventional example having such a configuration has the following problems.
The conventional example does not adjust the correction parameter for translating the image in the horizontal direction. Therefore, even if the image is corrected, the error due to the positional deviation cannot be sufficiently reduced.

  Further, the conventional example does not adjust the correction parameter during the actual operation of the stereo camera. For example, Patent Document 1 discloses only a method for adjusting a correction parameter, and does not disclose any timing for adjusting the correction parameter. Patent Document 2 discloses that correction parameters are adjusted before an automobile or the like equipped with a stereo camera enters actual operation. Here, before entering actual operation is, for example, when the vehicle is stationary.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an imaging device, a vehicle, and an image correction method capable of suitably adjusting correction parameters for translating an image in the horizontal direction. To do. It is another object of the present invention to provide a vehicle and an image correction method capable of adjusting correction parameters for correcting an image when a vehicle equipped with an image sensor is actually operating.

In order to achieve such an object, the present invention has the following configuration.
That is, the present invention is a photographing apparatus, and the photographing apparatus translates a pair of image sensors and an image photographed by at least one of the image sensors by a lateral shift amount in the lateral direction of the image. Each of the correction unit and the image sensor is located at a position where the distance away from the first marker in the optical axis direction is substantially equal to the distance away from the second marker in the optical axis direction. A horizontal shift amount adjusting unit that adjusts the horizontal shift amount based on the adjustment image, and the horizontal shift amount adjusting unit is included in both of the adjustment images. Based on a measurement unit that measures parallax related to at least one of the first marker and the second marker and obtains a parallax measurement value, and an interval between the first marker and the second marker A theoretical value calculation unit that calculates a theoretical value of parallax related to the first marker and the second marker based on one of the adjustment images, a measured value of the parallax, and a theoretical value of the parallax. A horizontal direction adjustment amount calculation unit that calculates a horizontal direction adjustment amount based on the horizontal direction adjustment amount, and a horizontal shift amount change unit that changes the horizontal shift amount using the horizontal direction adjustment amount, wherein at least one of the adjustment images is The horizontal shift amount change unit adds or subtracts the horizontal adjustment amount to the horizontal shift amount used by the image correction unit, and the photographing apparatus Further, when the horizontal shift amount is changed by the horizontal shift amount changing unit, the original image of the image for adjustment processed by the image correcting unit is used by using the changed horizontal shift amount. Re-correct the image again The theoretical value calculation unit includes the interval between the first marker and the second marker, the optical center associated with any one of the adjustment images, and the first on the adjustment image. Based on the projection point of one marker and the interior angle of a triangle having the projection point of the second marker on the adjustment image as a vertex, it is between the first marker, the second marker, and the image sensor. An imaging apparatus that calculates a distance in the optical axis direction and calculates a theoretical value of the parallax based on the distance.

  [Operation / Effect] The pair of image sensors constitutes a stereo camera. Each image sensor performs imaging by stereo vision.

  The image correction unit corrects the image using the horizontal shift amount. The lateral shift amount is one of correction parameters. The image correction unit may correct an image obtained from each image sensor, or may correct only an image obtained from any one of the image sensors.

  The horizontal shift amount adjustment unit adjusts the horizontal shift amount based on the adjustment image obtained from each image sensor.

  The adjustment image is a pair of images in which each image sensor captures the first marker and the second marker. The adjustment image is captured by each image sensor when the distance in the optical axis direction between the image sensor and the first marker is substantially equal to the distance in the optical axis direction between the image sensor and the second marker. It is an image. Here, “substantially equal” means that each distance is strictly equal and that each distance is approximated to such an extent that the lateral shift amount can be adjusted.

  As a result, the first marker and the second marker are projected on the adjustment image. In addition, the information in the depth direction of the first marker projected on the adjustment image is substantially equal to the information in the depth direction of the second marker projected on the adjustment image.

  The horizontal shift amount adjustment unit includes a measurement unit, a theoretical value calculation unit, a horizontal direction adjustment amount calculation unit, and a horizontal shift amount change unit. The measurement unit obtains a “parallax measurement value” based on the two adjustment images. The theoretical value calculation unit obtains a “theoretical value of parallax” based on one adjustment image. The horizontal direction adjustment amount calculation unit calculates the horizontal direction adjustment amount based on the “measurement value of parallax” and the “theoretical value of parallax”. The horizontal shift amount changing unit changes the horizontal shift amount using the horizontal adjustment amount.

  Thus, according to the present invention, since the horizontal shift amount adjusting unit is provided, the horizontal shift amount can be adjusted suitably. Thereby, the image correction unit can appropriately correct the image. That is, the parallax between the two images obtained from each image sensor can be suitably adjusted. Therefore, even if the position and orientation of the image sensor are deviated, the accuracy of the imaging device and the reliability of the imaging device can be suitably maintained.

  Further, the theoretical value calculation unit can calculate the theoretical value of parallax with high accuracy. As a result, the horizontal adjustment amount calculation unit can appropriately calculate the horizontal adjustment amount.

  The horizontal shift amount changing unit sets a value obtained by adding or subtracting the horizontal adjustment amount to or from the horizontal shift amount as a new horizontal shift amount. When at least one of the adjustment images is a corrected image, the lateral shift amount can be appropriately adjusted according to the present invention.

In the above-described invention, the theoretical value calculation unit is configured to determine whether the first marker, the second marker, and the image sensor are based on the positional relationship between the image sensor, the first marker, and the second marker. It is preferable that the distance in the optical axis direction is calculated, and the theoretical value of the parallax is calculated based on the distance. The theoretical value calculation unit can calculate the theoretical value of parallax with high accuracy. As a result, the horizontal adjustment amount calculation unit can appropriately calculate the horizontal adjustment amount.

  In the above-described invention, it is preferable that the horizontal direction adjustment amount calculation unit determines the horizontal direction adjustment amount so that a difference between the parallax measurement value and the parallax theoretical value is small. According to this, the actual parallax between two images obtained from each image sensor can be brought close to the theoretical value of parallax. As a result, the accuracy of information in the depth direction of the image can be preferably improved.

  In the above-described invention, in the imaging device, the image obtained from each of the image sensors based on the projection point of the first marker and the projection point of the second marker on the image is an adjustment image. It is preferable that an adjustment image specifying unit for determining whether or not to be included is provided. According to this, the adjustment image can be suitably specified.

  In the above-described invention, it is preferable that the first marker and the second marker are arranged at substantially the same height position. According to this, the process by the theoretical value calculation part can be simplified. Further, the processing by the adjustment image specifying unit can be simplified.

  In the above-described invention, the image correction unit further translates an image captured by at least one of the image sensors in the vertical direction of the image by a vertical shift amount, and the imaging device further includes the adjustment It is preferable to include a vertical shift amount adjustment unit that adjusts the vertical shift amount based on an image. The vertical shift amount is one of the correction parameters. Since the photographing apparatus includes the vertical shift amount adjustment unit, the vertical shift amount can be suitably adjusted. Therefore, the image correction unit can correct the image more appropriately.

  In the above-described invention, the image correction unit further rotates an image photographed by at least one of the image sensors by a rotation amount, and the photographing apparatus further calculates the rotation amount based on the adjustment image. It is preferable to provide a rotation amount adjustment unit for adjustment. The amount of rotation is one of the correction parameters. Since the photographing apparatus includes the rotation amount adjustment unit, the rotation amount can be adjusted appropriately. Therefore, the image correction unit can correct the image more appropriately.

  Further, the present invention is a vehicle, and the vehicle includes a photographing device, and the photographing device horizontally captures a pair of image sensors and an image photographed by at least one of the image sensors in a lateral direction of the image. Each of the image correction unit that translates the shift amount and the image sensor is located at a position where the distance away from the first marker in the optical axis direction is substantially equal to the distance away from the second marker in the optical axis direction. A horizontal shift amount adjustment unit that adjusts the horizontal shift amount based on the adjustment image, using images obtained by capturing the first marker and the second marker as adjustment images, respectively. A measurement unit that measures parallax related to at least one of the first marker and the second marker based on both of the adjustment images, and obtains a parallax measurement value; the first marker; and the second marker A theoretical value calculator that calculates a theoretical value of parallax related to the first marker and the second marker based on an interval between the first marker and the adjustment image, and a measured value of the parallax And a horizontal adjustment amount calculation unit that calculates a horizontal adjustment amount based on the theoretical value of the parallax, and a horizontal shift amount change unit that changes the horizontal shift amount using the horizontal adjustment amount, The first marker and the second marker are installed outside the vehicle, the first marker and the second marker are arranged so as to sandwich a runway, and when the vehicle travels on the runway, Each of the image sensors is a vehicle that photographs the first marker and the second marker.

  [Operation / Effect] According to the present invention, since the vehicle is provided with the photographing device, it is possible to suitably detect a subject around the vehicle. Moreover, since the precision and reliability of the imaging device are suitably maintained, it is possible to suitably suppress a reduction in the vehicle operating rate.

  Further, when the vehicle travels on the road, the image sensors capture the first marker and the second marker, respectively. According to this, the lateral shift amount can be adjusted when the vehicle is actually operating. Therefore, it is possible to maintain the accuracy of the photographing apparatus without reducing the operation rate of the vehicle.

  In the above-described invention, it is preferable that the travel path is determined in advance, and the vehicle autonomously travels on the travel path. Since the vehicle travels on a predetermined road, the image sensor can appropriately capture the first marker and the second marker. Thereby, the theoretical value calculation unit can calculate the “theoretical value of parallax” with higher accuracy.

In addition, the present invention provides a process in which a plurality of image sensors mounted on a vehicle capture a group of markers installed outside the vehicle when the vehicle is traveling, and at least one of the image sensors. And a correction used in the process of correcting the image based on the adjustment image, using the image obtained from the image sensor and the image on which the marker group is projected as the adjustment image. Adjusting the parameters, wherein the marker group includes a first marker and a second marker, the first marker and the second marker are arranged so as to sandwich a straight running path, and the correction parameter is The process of correcting the image is a shift amount, and the image is translated in the lateral direction of the image by the lateral shift amount, and the first marker and the second marker are spaced apart from each other. When performing the shooting process, the distance in the optical axis direction between the image sensor and the first marker is substantially equal to the distance in the optical axis direction between the image sensor and the second marker, The process of adjusting the correction parameter includes measuring a parallax related to at least one of the first marker and the second marker based on both of the adjustment images, and acquiring a parallax measurement value; A process of calculating a theoretical value of parallax regarding the first marker and the second marker based on the interval between the marker and the second marker and one of the adjustment images, and measurement of the parallax An image correction method comprising: a step of calculating a horizontal adjustment amount based on a value and a theoretical value of the parallax; and a step of changing the horizontal shift amount using the horizontal adjustment amount .

  [Operation / Effect] In the process of photographing, the marker group is photographed while the vehicle is running. In the correction process, the image obtained from the image sensor is corrected. In the adjustment process, the correction parameter is adjusted based on the adjustment image. Thus, according to the present invention, it is possible to appropriately adjust the correction parameter for correcting the image while actually operating the vehicle.

  In the process of photographing, each image sensor photographs the first marker and the second marker at a position separated from the first marker and the second marker by a substantially equal distance in the optical axis direction. Here, “substantially equal” means that each distance is exactly the same and that each distance is approximated to such an extent that the lateral shift amount can be adjusted.

  In the correction process, the horizontal shift amount is used to translate the image in the horizontal direction.

  In the process of adjusting the correction parameter, the lateral shift amount is adjusted based on the adjustment image. The process of adjusting the correction parameter further includes a process of acquiring a parallax measurement value, a process of calculating a parallax theoretical value, a process of calculating a lateral adjustment amount, and a process of changing a lateral shift amount. . For this reason, the process of adjusting the correction parameter can appropriately adjust the lateral shift amount.

  Thereby, the process of correcting the image can appropriately correct the image. As a result, the parallax between the images obtained from the image sensors can be suitably adjusted. Therefore, even if the position and orientation of the image sensor are shifted, information in the depth direction of the image can be obtained with high accuracy.

In addition, the present invention provides a process in which a plurality of image sensors mounted on a vehicle capture a group of markers installed outside the vehicle when the vehicle is traveling, and at least one of the image sensors. And a correction used in the process of correcting the image based on the adjustment image, using the image obtained from the image sensor and the image on which the marker group is projected as the adjustment image. Adjusting the parameters, wherein the marker group includes a first marker and a second marker, the first marker and the second marker are arranged so as to sandwich a straight running path, and the plurality of image sensors Constitutes a stereo camera, the correction parameter is a horizontal shift amount, and the process of correcting the image is an image correction in which the image is translated in the horizontal direction of the image by the horizontal shift amount. It is the law.

  [Operation / Effect] In the process of photographing, the marker group is photographed while the vehicle is running. In the correction process, the image obtained from the image sensor is corrected. In the adjustment process, the correction parameter is adjusted based on the adjustment image. Thus, according to the present invention, it is possible to appropriately adjust the correction parameter for correcting the image while actually operating the vehicle.

  In the correction process, the horizontal shift amount is used to translate the image in the horizontal direction.

  The present specification also discloses the invention relating to the following detection device and vehicle.

  (1) In the above-described invention, it is preferable that the first marker and the second marker are arranged at a known interval.

  According to (1), the theoretical value calculation unit can preferably calculate the theoretical value of parallax.

  (2) In the above-described invention, each of the image sensors is arranged so that the optical axes of the image sensors are parallel to each other, and the horizontal axis of an image obtained from each image sensor is coaxial. Preferably it is.

  According to said (2), a stereo camera can be suitably comprised by each image sensor.

  (3) In the above-described invention, the theoretical value calculation unit may include the interval between the first marker and the second marker, the optical center associated with any one of the adjustment images, and the adjustment image. The first marker, the second marker, and the image sensor based on the projection point of the first marker in the image and the interior angle of a triangle having the projection point of the second marker on the adjustment image as a vertex It is preferable to calculate a distance in the optical axis direction between and a theoretical value of the parallax based on the distance.

  According to (3), the theoretical value calculator can calculate the theoretical value of parallax with high accuracy. As a result, the horizontal adjustment amount calculation unit can appropriately calculate the horizontal adjustment amount.

  (4) In the above-described invention, the theoretical value calculation unit may include the interval between the first marker and the second marker, the optical center associated with any one of the adjustment images, and the adjustment image. , The projection point of the first marker, the interior angle of a triangle whose apex is the projection point of the second marker on the adjustment image, and the positional relationship between the image sensor, the first marker, and the second marker It is preferable to calculate the distance in the optical axis direction between the first marker and the second marker and the image sensor based on the above and calculate the theoretical value of the parallax based on the distance.

  According to (4) above, the theoretical value calculator can calculate the theoretical value of parallax with high accuracy. As a result, the horizontal adjustment amount calculation unit can appropriately calculate the horizontal adjustment amount.

  According to the photographing apparatus, the vehicle, and the image correction method according to the present invention, the correction parameter for translating the image in the horizontal direction can be suitably adjusted. Therefore, the reliability of the photographing apparatus can be improved. Further, when a vehicle equipped with an image sensor is actually operating, a correction parameter for correcting an image can be adjusted. Therefore, it can prevent that the operation rate of a vehicle falls.

1 is a front view of a vehicle according to an embodiment. It is a top view of a vehicle and a runway. It is a side view of a vehicle and a marker. It is a front view of a marker. It is a block diagram which shows the structure of the imaging device which concerns on an Example. FIG. 6A and FIG. 6B are diagrams schematically illustrating images. FIG. 7A and FIG. 7B are diagrams schematically illustrating projection points in an image. It is explanatory drawing of the method of calculating the distance in the optical axis direction between a camera and a marker. It is a flowchart which shows the operation example of an imaging device. It is explanatory drawing of the modification Example of the method of calculating the distance in the optical axis direction between a camera and a marker. It is a block diagram which shows the structure of the imaging device which concerns on a modified example.

  Embodiments of the present invention will be described below with reference to the drawings.

1. FIG. 1 is a front view of a vehicle 1 according to an embodiment, and FIG. 2 is a plan view of the vehicle 1 and a runway T. In the present embodiment, the vehicle 1 is a golf cart that travels in a golf course. A runway T is laid in advance in the golf course. The vehicle 1 travels autonomously on the track T. The vehicle 1 travels on the track T repeatedly. The traveling of the vehicle 1 on the track T is that the vehicle 1 is actually operated.

  In this specification, the direction in which the vehicle 1 travels is referred to as “front direction Zf”, and the direction opposite to the front direction is referred to as “rear direction Zb” (see FIG. 3). The user gets on the vehicle 1 in a posture facing the front direction Zf. In the following description, “right”, “left”, “upper”, and “lower” mean “right”, “left”, “upper”, and “lower” for the user who has boarded the vehicle 1, respectively. Further, when there is no particular distinction between the front direction Zf and the rear direction Zb, it is simply referred to as “front-rear direction Z”. Further, the left-right direction is appropriately referred to as “lateral direction X”. The front-rear direction Z, the horizontal direction X, and the vertical direction Y are orthogonal to each other.

  The vehicle 1 includes a vehicle body 3 and a pair of cameras 11R and 11L. The cameras 11R and 11L constitute a stereo camera. Each camera 11R, 11L is fixed to the front surface of the vehicle body 3.

  When the cameras 11R and 11L are not “displaced”, the arrangement and posture of the cameras 11R and 11L are so-called parallel stereo. That is, the optical axis AR of the camera 11R and the optical axis AL of the left camera 11L are parallel to each other. In the present embodiment, the optical axes AR and AL are parallel to the front direction Zf. The cameras 11R and 11L are arranged in the horizontal direction X with a predetermined distance (baseline length) therebetween. The camera 11R is disposed on the right side of the camera 11L. Hereinafter, the cameras 11R and 11L are appropriately referred to as “right camera 11R” and “left camera 11L”.

  The cameras 11R and 11L perform shooting by stereo viewing. Each camera 11R, 11L can simultaneously photograph the same subject. The subject is, for example, the ground, a runway, a tree, or an obstacle.

  Each camera 11R, 11L is, for example, a visible light camera. Each of the cameras 11R and 11L is realized by a CMOS (Complementary Metal Oxide Semiconductor) sensor, a CCD (Charge coupled Device) sensor, or the like. The cameras 11R and 11L are examples of image sensors in the present invention.

  As shown in FIG. 2, a marker group MG is installed near the track T. The marker group MG includes two markers M1 and M2. The markers M1 and M2 are arranged so as to sandwich the runway T, respectively. The distance LM between the marker M1 and the marker M2 is known. In this specification, “distance LM” is appropriately described as “interval LM”.

  Please refer to FIG. 2 and FIG. FIG. 3 is a side view of the vehicle 1 and the markers M1 and M2. In the present embodiment, when the vehicle 1 is in the section Tab from the point Ta to the point Tb on the track T, each of the cameras 11R and 11L can capture both the markers M1 and M2. Hereinafter, the section Tab is appropriately referred to as “marker group photographing section Tab”.

  Since the marker group photographing section Tab is linear, when the vehicle 1 is in the marker group photographing section Tab, the optical axis AR / AL is substantially constant. As shown in FIG. 3, in a side view, the optical axis AR / AL is substantially parallel to the road surface in the marker group photographing section Tab.

  Here, one plane substantially perpendicular to the optical axis AR / AL when the vehicle 1 is in the section Tab is referred to as a “plane P”. The markers M1 and M2 are arranged so as to be positioned on the plane P, respectively. As a result, when the vehicle 1 is in the marker group photographing section Tab, the distance between the cameras 11R and 11L being away from the marker M1 in the optical axis direction AR / AL, and the cameras 11R and 11L being away from the marker M2 in the optical axis direction AR / AL. The distance that is far away is approximately equal.

  More detailed description will be given. When the vehicle 1 is in the marker group photographing section Tab, the following relationship is established. The distance D1R in the optical axis AR direction between the right camera 11R and the marker M1 and the distance D2R in the optical axis AR direction between the right camera 11R and the marker M2 are substantially equal. In addition, the distance D1L in the optical axis AL direction between the left camera 11L and the marker M1 and the distance D2L in the optical axis AL direction between the left camera 11L and the marker M2 are substantially equal. Moreover, since the right camera 11R and the left camera 11L constitute a stereo camera, the distances D1R and D2R and the distances D1L and D2L are substantially equal. Hereinafter, when the distances D1R, D2R, D1L, and D2L are not particularly distinguished, they are simply referred to as “distance D”. The distance D corresponds to the distance between the camera 11R / 11L and the plane P. The “distance away from the optical axis direction AR / AL” and the “distance in the optical axis direction AR / AL” mean the distance of the component in the optical axis direction AR / AL.

  FIG. 4 is a front view of the markers M1 and M2. The markers M1 and M2 are respectively displayed on the front surface of the marker support tool 15. In the present embodiment, the marker M1 and the marker M2 are arranged at substantially the same height position. The markers M1 and M2 are examples of the first marker and the second marker in the present invention.

2. Configuration of Imaging Device Next, the configuration of the imaging device 5 will be described. FIG. 5 is a block diagram illustrating a configuration of the photographing apparatus.

  The vehicle 1 includes a photographing device 5. The imaging device 5 includes an image processing unit 13 in addition to the cameras 11R and 11L described above. The image processing unit 13 processes the image IR photographed by the right camera 11R and the image IL photographed by the left camera 11L. Note that “image IR” or the like means image information that can be processed by the image processing unit 13. The image processing unit 13 is realized by, for example, a central processing unit (CPU) and a storage unit.

  6A and 6B schematically illustrate a pair of images IR and IL. “A pair of images IR and IL” means a combination of images IR and IL taken simultaneously.

  The position on the image IR is represented by coordinates composed of a horizontal axis uR and a vertical axis vR. The horizontal axis uR is parallel to the horizontal direction of the image IR, and the vertical axis vR is parallel to the vertical direction of the image IR. The image center OR corresponds to the intersection of the image IR and the optical axis AR.

  The position on the image IL is represented by coordinates composed of a horizontal axis uL and a vertical axis vL. The horizontal axis uL is parallel to the horizontal direction of the image IL, and the vertical axis vL is parallel to the vertical direction of the image IL. The image center OL corresponds to the intersection of the image IL and the optical axis AL.

  FIG. 6B illustrates a case where the left camera 11L is displaced. However, if the cameras 11R and 11L are not displaced, the horizontal axis uR and the horizontal axis uL are coaxial, and the vertical axis vR and the vertical axis vL are parallel. If the cameras 11R and 11L are not displaced, the horizontal axes uR and uL are parallel to the horizontal direction X, and the vertical axes vR and vL are parallel to the vertical direction Y. Furthermore, if the cameras 11R and 11L are not misaligned, the parallax regarding the markers M1 and M2 between the images IR and IL corresponds to the distance D at the time when the images IR and IL are captured.

  Please refer to FIG. The image processing unit 13 includes a correction parameter storage unit 21, an image correction unit 22, an image storage unit 23, an image re-correction unit 24, an adjustment image specifying unit 25, an imaging condition storage unit 26, and a lateral shift amount. An adjustment unit 27, a vertical shift amount adjustment unit 28, and a rotation amount adjustment unit 29 are included. Hereinafter, each part 21 thru | or 29 is demonstrated.

  The correction parameter storage unit 21 stores correction parameters. The correction parameters are, for example, a horizontal shift amount Bh, a vertical shift amount Bv, and a rotation amount Br. As shown in FIG. 6B, the horizontal shift amount Bh is a movement amount in the direction of the horizontal axis uL. The vertical shift amount Bv is a movement amount in the direction of the vertical axis vL. The rotation amount Br is an angle in the rotation direction. Note that the center of rotation is, for example, the image center OL. The correction parameters Bh, Bv, Br are expressed in an appropriate format. For example, the correction parameters Bh, Bv, and Br may be represented by a correction map or determinant.

  The image correction unit 22 corrects the image IL using the correction parameters Bh, Bv, Br stored in the correction parameter storage unit 21. Specifically, the image correction unit 22 translates the image IL by the horizontal shift amount Bh in the horizontal direction of the image IL, translates the image IL by the vertical shift amount Bv in the vertical direction of the image IL, and sets the image center OL. The image IL is rotated around the rotation amount Br.

  By the correction, the pixel at each position (uL, vL) on the image IL is moved to a new position (u + Δ, vL + Δ), for example. The pixel value at the original position (uL, vL) defines the pixel value at the new position (uL + Δ, vL + Δ). As a result of this correction, an image ILc is generated.

  The image storage unit 23 stores the image IL.

  When at least one of the correction parameters Bh, Bv, and Br stored in the correction parameter storage unit 21 is changed, the image re-correction unit 24 uses the latest correction parameters Bh, Bv, and Br to calculate the image IL. Correct again. The correction itself is the same as the correction performed by the image correction unit 22.

  The adjustment image specifying unit 25 determines whether the pair of images IR and ILc are the adjustment images ER and EL, respectively. Specific processing of the adjustment image specifying unit 25 is exemplified below.

  FIG. 7A is a diagram schematically showing projection points mR1 and mR2, which are points where the markers M1 and M2 are projected on the image IR, and FIG. 7B shows the markers M1 and M2 on the image ILc. It is a figure which shows typically projection point mL1, mL2 which is the point projected on the top. As shown in FIG. 7A, the adjustment image specifying unit 25 detects projection points mR1 and mR2 of the markers M1 and M2 on the image IR based on the image IR. As illustrated in FIG. 7B, the adjustment image specifying unit 25 detects the projection points mL1 and mL2 of the markers M1 and M2 on the image ILc based on the image ILc. When detecting the projection points mR1, mR2, mL1, and mL2, the adjustment image specifying unit 25 performs, for example, template matching using templates related to the markers M1 and M2.

  Here, the adjustment image specifying unit 25 may or may not identify whether the projection point mR1 is the projection point of the marker M1 or the marker M2. The same applies to the other projection points mR2, mL1, and mL2. Hereinafter, when the projection points mR1 and mR2 are not particularly distinguished, they are described as “projection points mR”, and when the projection points mL1 and mL2 are not particularly distinguished, they are described as “projection points mL”. Further, when the projection points mR and mL are not particularly distinguished, “projection point m” is described.

  Based on the projection point m, the adjustment image specifying unit 25 determines whether the images IR and ILc are the adjustment images ER and EL, respectively. Specifically, the determination process is performed based on the number of projection points m and the position of each projection point m.

For example, the adjustment image specifying unit 25 determines whether or not the projection point m satisfies all of the following determination conditions 1 to 4.
Determination condition 1: The number of projection points mR of the image IR is two.
Determination condition 2: The difference ΔvR between the vertical position vR1 of one projection point mR1 and the vertical position vR2 of the other projection point mR2 is equal to or less than a threshold value.
Judgment condition 3: The number of projection points mL of the image IL is two.
Determination condition 4: The difference ΔvL between the vertical position vL1 of one projection point mL1 and the vertical position vL2 of the other projection point mL2 is equal to or less than a threshold value.

  The threshold value is, for example, 10 pixels. When it is determined that the projection point m satisfies the determination conditions 1 to 4, the adjustment image specifying unit 25 specifies the image IR as the adjustment image ER and specifies the image ILc as the adjustment image EL. Otherwise, the images IR and IL are not identified as the adjustment images ER and EL.

  The imaging condition storage unit 26 stores information related to the interval LM between the markers M1 and M2. The imaging condition storage unit 26 further stores internal parameters and external parameters of the right camera 11R and the left camera 11L.

  The lateral shift amount adjustment unit 27 adjusts the lateral shift amount Bh stored in the correction parameter storage unit 21 based on the adjustment images ER and EL. The lateral shift amount adjustment unit 27 includes a measurement unit 31, a theoretical value calculation unit 32, a lateral direction adjustment amount calculation unit 33, and a lateral shift amount change unit 34. Hereinafter, each part 31 thru | or 34 is demonstrated.

  The measurement unit 31 measures the parallax related to any of the markers M1 and M2 based on the adjustment images ER and EL, and obtains a parallax measurement value Fm. Specific processing of the measurement unit 31 is exemplified below.

  The measurement unit 31 identifies the correspondence between the projection point mR of the adjustment image ER and the projection point mL of the adjustment image EL. When identifying the correspondence, the measurement unit 31 performs, for example, stereo matching. Thereby, the measurement unit 31 specifies that the projection point mR1 and the projection point mL1 correspond and that the projection point mR2 and the projection point mL2 correspond.

  Subsequently, the measurement unit 31 measures the difference between the position in the lateral direction of any projection point mR and the position in the lateral direction of the projection point mL corresponding to the projection point mR. The measurement unit 31 sets the measured difference as the parallax measurement value Fm regarding either of the markers M1 and M2.

  The theoretical value calculator 32 calculates a parallax theoretical value Ft based on the adjustment image ER and the interval LM. The theoretical value Ft of parallax is the parallax related to the markers M1 and M2 that should be obtained when it is assumed that the right camera 11R and the left camera 11L are not displaced.

  More specifically, the theoretical value calculation unit 32 estimates the distance between the camera 11R and the plane P based on the adjustment image ER and the interval LM. This estimation is synonymous with calculating the distances D1R and D2R in the optical axis direction AR between the camera 11R and the markers M1 and M2, and the distance in the optical axis direction AL between the camera 11L and the markers M1 and M2. It is synonymous with calculating D1L and D2L. In other words, the estimated distance corresponds to “distance D”. Then, the theoretical value calculator 32 calculates a parallax theoretical value Ft based on the distance D.

  First, a method for estimating the distance D will be described with reference to FIG. FIG. 8 is a diagram in which the adjustment image ER is modeled. In FIG. 8, the optical axis AR is orthogonal to the plane P at the point QR. The modeled adjustment image ER is located on a plane orthogonal to the optical axis AR. In other words, the modeled adjustment image ER is parallel to the plane P. The point where the optical axis direction AR is orthogonal to the adjustment image ER corresponds to the image center OR. The optical center CR of the right camera 11R is located on the optical axis direction AR.

  The projection points mR1 and mR2 are on the adjustment image ER, and the markers M1 and M2 are on the plane P. The marker M1 is located on the line J1 connecting the optical center CR and the projection point mR1, and the marker M2 is located on the line J2 connecting the optical center CR and the projection point mR2. A triangle whose vertex is the optical center CR, the projection point mR1, and the projection point mR2 is similar to a triangle whose vertex is the optical center CR, the marker M1, and the marker M2.

  Here, the optical center CR is regarded as the exact position of the right camera 11R, and the distance D is the distance between the optical center CR and the plane P (point QR). Further, the distance between the optical center CR and the adjustment image ER (image center OR) is defined as “focal length d”. Further, the distance between the projection point mR1 and the projection point mR2 is defined as an “interval Lm”. The interval LM between the markers M1 and M2 is a distance on the real space, whereas the interval Lm is a distance on the adjustment image ER. Then, the ratio between the distance Lm and the distance LM is equal to the ratio between the focal distance d and the distance D. That is, the following relational expression holds.

  Lm / LM = d / D (1)

  Note that the interval LM is known. The interval Lm is given from the adjustment image ER (projection points mR1, mR2). The focal length d is given from an internal parameter of the right camera 11R. The distance D is uniquely determined by the distance LM, the distance Lm, and the focal length d.

  Next, specific processing of the theoretical value calculation unit 32 is exemplified below. The theoretical value calculation unit 32 reads the interval LM and the internal parameters of the right camera 11R from the imaging condition storage unit 26. The theoretical value calculation unit 32 acquires the focal length d based on the internal parameters of the right camera 11R. The theoretical value calculator 32 obtains an interval Lm between the projection point mR1 and the projection point mR2 based on the adjustment image ER. The theoretical value calculator 32 calculates the distance D by substituting the distance Lm, the distance LM, and the focal distance d into the relational expression (1). Further, the theoretical value calculation unit 32 calculates a theoretical value Ft of parallax related to the markers M1 and M2 based on the distance D and the internal parameters and external parameters of the cameras 11R and 11L.

  The horizontal adjustment amount calculation unit 33 calculates the horizontal adjustment amount Hh based on the parallax measurement value Fm and the parallax theoretical value Ft. The horizontal direction adjustment amount calculation unit 33 preferably determines the horizontal direction adjustment amount Hh so that the parallax measurement value Fm is equal to the parallax theoretical value Ft. The horizontal adjustment amount Hh is, for example, the difference between the parallax measurement value Fm and the parallax theoretical value Ft.

  The horizontal shift amount changing unit 34 changes the horizontal shift amount Bh based on the horizontal adjustment amount Hh. In this embodiment, the lateral shift amount changing unit 34 adds or subtracts the lateral adjustment amount Hh to the lateral shift amount Bh stored in the correction parameter storage unit 21. The calculated value is stored in the correction parameter storage unit 21 as a new lateral shift amount Bh.

  The vertical shift amount adjustment unit 28 adjusts the vertical shift amount Bv based on the adjustment images ER and EL. The vertical shift amount adjustment unit 28 includes a vertical direction adjustment amount calculation unit 36 and a vertical shift amount change unit 37.

  The vertical adjustment amount calculation unit 36 calculates the vertical adjustment amount Hv based on one or more sets of projection points mR and points mL that are in a correspondence relationship. The vertical adjustment amount calculation unit 36 may determine the vertical adjustment amount Hv so that the position of the projection point mR in the vertical direction is equal to the position of the projection point mL corresponding to the projection point mR in the vertical direction. preferable. When the projection point mR1 and the projection point mL1 are in a correspondence relationship, the vertical adjustment amount Hv is, for example, the difference between the position vR1 in the vertical direction of the projection point mR1 and the position vL1 in the vertical direction of the projection point mL1.

  The vertical shift amount changing unit 37 changes the vertical shift amount Bv based on the vertical adjustment amount Hv. In the present embodiment, the vertical shift amount changing unit 37 adds or subtracts the vertical adjustment amount Hv to the vertical shift amount Bv stored in the correction parameter storage unit 21. The calculated value is stored in the correction parameter storage unit 21 as a new vertical shift amount Bv.

  The rotation amount adjustment unit 29 adjusts the rotation amount based on the adjustment images ER and EL. The rotation amount adjustment unit 29 includes a rotation direction adjustment amount calculation unit 38 and a rotation amount change unit 39.

  The rotation direction adjustment amount calculation unit 38 calculates the rotation direction adjustment amount Hr based on two or more sets of projection points mR and mL having a correspondence relationship. Referring to FIG. 7, rotation direction adjustment amount calculation unit 38 rotates so that the inclination of virtual line KR connecting projection points mR1 and mR2 is equal to the inclination of virtual line KL connecting projection points mL1 and mL2. It is preferable to determine the direction adjustment amount Hr. The rotation direction adjustment amount Hr is, for example, an angle formed by the virtual line KR and the virtual line KL.

  The rotation amount changing unit 39 changes the rotation amount Br based on the rotation direction adjustment amount Hr. In this embodiment, the rotation amount changing unit 39 adds or subtracts the rotation direction adjustment amount Hr to the rotation amount Br stored in the correction parameter storage unit 21. The calculated value is stored in the correction parameter storage unit 21 as a new rotation amount Br.

  The imaging device 5 may further include a stereo processing unit (not shown) that processes the images IR and ILc. For example, the stereo processing unit may calculate information in the depth direction of the images IR and ILc based on the images IR and ILc. For example, the stereo processing unit may calculate the distance to the subject in the optical axis direction AR / AL based on the images IR and ILc. For example, the stereo processing unit may detect an obstacle that prevents the vehicle 1 from traveling based on the images IR and ILc.

3. Description of Operation Next, the operation of the vehicle 1 according to the embodiment will be described. FIG. 9 is a flowchart showing an example of the operation of the photographing apparatus 5. In the following description, it is assumed that the vehicle 1 is traveling on the track T. That is, an operation example performed by the photographing device 5 when the vehicle 1 is traveling will be described below.

<Step S1> Shooting The right camera 11R and the left camera 11L capture images IR and IL, respectively.

<Step S2> Image Capture The image processing unit 13 captures the images IR and IL. The image IL is stored in the image storage unit 23.

<Step S3> Image Correction The image correction unit 22 reads the latest horizontal shift amount Bh, vertical shift amount Bv, and rotation amount Br from the correction parameter storage unit 21. The image correction unit 22 corrects the image IL using the read correction parameters Bh, Bv, and Br. Thereby, the image correction unit 22 generates the image ILc.

<Step S4> Is the image for adjustment?
The adjustment image specifying unit 25 detects the projection point mR based on the image IR. The adjustment image specifying unit 25 detects the projection point mL based on the image ILc. The adjustment image specifying unit 25 determines whether the images IR and ILc are the adjustment images ER and EL based on the projection points mR and mL. If it is determined that the images IR and ILc are the adjustment images ER and EL, the process proceeds to step S5. Otherwise, the process returns to step S1.

<Step S5> Calculation of Adjustment Amount The horizontal shift amount adjustment unit 27 calculates a horizontal adjustment amount Hh. Specifically, the measurement unit 31 acquires a parallax measurement value Fm based on the adjustment images ER and EL. The theoretical value calculation unit 32 acquires a parallax theoretical value Ft based on the adjustment image ER. The horizontal adjustment amount calculation unit 33 calculates the horizontal adjustment amount Hh based on the parallax measurement value Fm and the parallax theoretical value Ft.

  In parallel with the processing described above, the vertical adjustment amount calculation unit 36 calculates the vertical adjustment amount Hv based on the adjustment images ER and EL. The rotation direction adjustment amount calculation unit 38 calculates a rotation direction adjustment amount Hr based on the adjustment images ER and EL.

<Step S6> Change of Correction Parameter The lateral shift amount changing unit 34 changes the lateral shift amount Bh using the lateral adjustment amount Hh. The vertical shift amount changing unit 37 changes the vertical shift amount Bv using the vertical adjustment amount Hv. The rotation amount changing unit 39 changes the rotation amount Br using the rotation direction adjustment amount Hr.

<Step S <b>7> Image Recorrection The image recorrection unit 24 reads the image IL from the image storage unit 23, and reads the changed correction parameters Bh, Bv, and Br from the correction parameter storage unit 21. Then, the image re-correction unit 24 corrects the image IL using the correction parameters Bh, Bv, and Br. Then, it returns to step S1.

  Thus, according to the embodiment, since the photographing apparatus 5 includes the lateral shift amount adjustment unit 27, the lateral shift amount Bh can be suitably adjusted. Therefore, the image correction unit 22 can translate the image IL in the horizontal direction using the appropriate horizontal shift amount Bh. Thereby, the parallax of the images IR and ILc is closer to the parallax theoretical value Ft than the parallax of the images IR and IL. Therefore, even when the cameras 11R and 11L are displaced, information about the subject in the depth direction can be obtained with high accuracy based on the images IR and ILc. Thus, even if the positions and postures of the cameras 11R and 11L are deviated, the accuracy and reliability of the imaging device 5 can be suitably maintained. As a result, it is possible to suitably prevent the operating rate of the vehicle 1 from decreasing.

  In particular, the theoretical value calculation unit 32 calculates the theoretical value Ft of parallax using one of the adjustment images ER without using both the adjustment images ER and EL. This calculation method is less susceptible to the displacement of the cameras 11R and 11L than when both the adjustment images ER and EL are used. Therefore, the theoretical value calculation unit 32 can acquire the theoretical value Ft of parallax with high accuracy.

  The theoretical value calculation unit 32 utilizes the relationship between the distance LM between the markers M1 and M2 and the distance Lm between the projection points mR1 and mR2, and the optical axis direction AR / AL between the camera 11R / 11L and the markers M1 and M2. The distance D at is calculated. Thereby, the theoretical value calculator 32 can suitably calculate the theoretical value Ft of parallax.

  The measurement unit 31 acquires a “parallax measurement value Fm” corresponding to the actual parallax between the image IR and the image ILc. Therefore, the horizontal adjustment amount calculation unit 33 can grasp the deviation between the parallax measurement value Fm and the parallax theoretical value Ft. As a result, the horizontal adjustment amount calculation unit 33 can determine an appropriate horizontal adjustment amount Hh. In particular, when the horizontal adjustment amount Hh is the difference between the parallax measurement value Fm and the parallax theoretical value Ft, the actual parallax between the image IR and the image ILc may be matched with the parallax theoretical value Ft. it can.

  Further, since the lateral shift amount adjusting unit 27 includes the lateral shift amount changing unit 34, the lateral shift amount Bh stored in the correction parameter storage unit 21 can be suitably updated. In this embodiment, since the adjustment image EL is the image ILc corrected by the image correction unit 22, the horizontal shift amount changing unit 34 uses the horizontal shift amount Bh used for generating the adjustment image EL. The horizontal adjustment amount Hh is added or subtracted. Thereby, the amount of horizontal shift can be adjusted suitably.

  Further, since the adjustment image specifying unit 25 is provided, the images IR and ILc in which the markers M1 and M2 are appropriately photographed can be suitably specified.

  In addition, since the vertical shift amount adjustment unit 28 is provided, the vertical shift amount Bh can be suitably adjusted. Therefore, the image correction unit 22 can correct the image IL more appropriately.

  Further, since the rotation amount adjustment unit 29 is provided, the rotation amount Br can be adjusted appropriately. Therefore, the image correction unit 22 can correct the image IL more appropriately.

  Further, the marker group photographing section Tab can be suitably formed on the runway T by appropriately arranging the markers M1 and M2 in consideration of the layout of the runway T and the optical axes AR / AL of the cameras 11R and 11L. Thereby, the images for adjustment ER and EL can be suitably obtained.

  Specifically, the markers M1 and M2 are installed so that the cameras 11R and 11L can photograph both the markers M1 and M2 in the linear marker group photographing section Tab. Further, markers M1 and M2 are arranged on a plane P substantially perpendicular to the optical axis AR / AL of the cameras 11R and 11L in the marker group photographing section Tab. Here, “substantially vertical” means to include both being strictly vertical and being nearly vertical to the extent that the lateral shift amount Bh can be appropriately adjusted.

  For this reason, in the marker group photographing section Tab, the camera 11R can simultaneously photograph a plurality of markers M1 and M2 that are separated by substantially the same distance in the optical axis direction AR. Here, “substantially the same” means to include both being exactly equal and approximating to the extent that the lateral shift amount Bh can be appropriately corrected. Therefore, the theoretical value calculation unit 32 can accurately estimate the distance D based on the image IR and can calculate the parallax theoretical value Ft with high accuracy. In the marker group photographing section Tab, the camera 11L can photograph the markers M1 and M2 similarly to the camera 11R. Therefore, the measurement unit 31 can suitably acquire the parallax measurement value Fm based on the images IR and ILc.

  Furthermore, the markers M1 and M2 are arranged at substantially the same height position. Thereby, the process in which the theoretical value calculation part 32 calculates the space | interval Lm of projection point mR1, mR2 can be simplified. Further, it is possible to simplify the process in which the adjustment image specifying unit 25 determines whether the position of each projection point m satisfies the determination conditions 2 and 4.

  Further, since the marker group photographing section Tab described above is a part of the track T, when the vehicle 1 is actually operating, the cameras 11R and 11L can suitably photograph the markers M1 and M2, and the image processing unit 13 The correction parameters Bh, Bv, Br can be suitably adjusted. Therefore, the accuracy and reliability of the imaging device 5 can be suitably maintained without reducing the operating rate of the vehicle 1.

  In addition, since the track T is determined in advance, the markers M1 and M2 can be set in appropriate positions in advance. Therefore, the cameras 11R and 11L can appropriately photograph the markers M1 and M2. Therefore, the image processing unit 13 can adjust the correction parameters Bh, Bv, Br more accurately.

  The present invention is not limited to the above embodiment, and can be modified as follows.

  (1) In the above-described embodiment, the theoretical value calculation unit 32 calculates the distance D based on the interval LM and the interval Lm, but is not limited thereto. For example, the theoretical value calculator 32 may calculate the distance D by a triangulation technique or a technique using geometry.

  With reference to FIG. 10, a method for estimating the distance D using a triangulation method will be described as an example of a method according to a modified embodiment. FIG. 10 is a diagram modeling the adjustment image ER. In addition, about the same structure as an Example, detailed description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  In FIG. 10, a straight line J3 is a line connecting the projection point mR1 and the projection point mR2. The straight line J4 is a line connecting the marker M1 and the marker M2. The angle α is an angle formed by the straight line J1 and the straight line J3. The angle β is an angle formed by the straight line J2 and the straight line J3. The angles α and β correspond to inner angles of a triangle having the optical center CR, the projection point mR1, and the projection point mR2 as vertices, respectively. This triangle is similar to the triangle having the optical center CR, the marker M1, and the marker M2 as vertices. Therefore, the angle α is equal to the angle formed by the straight line J1 and the straight line J4, and the angle β is equal to the angle formed by the straight line J2 and the straight line J4.

  Here, the point QR ′ is a point perpendicular to the straight line J4 from the optical center CR. The distance between the optical center CR and the point QR ′ is defined as “distance Da”.

Then, the distance Da is expressed by the following formula (2) using a triangulation method.
Da = LMsinαsinβ / sin (α + β) (2)

  A triangle whose apexes are the optical center CR, the point QR, and the point QR ′ is a right triangle. Here, the distance between the point QR and the point QR ′ is defined as “distance Db”. The distance Db is calculated based on the positional relationship between the camera 11R and the markers M1 and M2. As a relatively simple example, the distance Db is the difference between the height of the camera 11R and the heights of the markers M1 and M2. As a relatively complicated example, the distance Db is calculated using the position and angle of the camera 11R and the positions of the markers M1 and M2.

According to the three square theorem, the distance D is expressed by the following equation (3).

  When such a triangulation method is used, the theoretical value calculation unit 32 calculates the distance Da based on the interval LM and the internal angles α and β of the triangle having the optical center CR and the projection points mR1 and mR2 as vertices. To do. Specifically, the theoretical value calculation unit 32 reads the interval LM and the internal parameters of the right camera 11R from the imaging condition storage unit 26. The theoretical value calculation unit 32 calculates the relative positional relationship between the optical center CR and the projection points mR1, mR2 based on the adjustment image ER and internal parameters, and the relative positions of the optical center CR and the projection points mR1, mR2. The angles α and β are calculated based on the relationship. The theoretical value calculation unit 32 calculates the distance Da by substituting the interval LM and the angles α and β into the relational expression (2).

  Subsequently, the theoretical value calculation unit 32 reads the external parameters of the right camera 11R and the positions of the markers M1 and M2 from the imaging condition storage unit 26. Note that the positions of the markers M1 and M2 are also stored in the imaging condition storage unit 26 in advance. The theoretical value calculator 32 calculates the distance Db based on the external parameters of the right camera 11R and the positions of the markers M1 and M2. Further, the theoretical value calculation unit 32 calculates the distance D using the relational expression (3).

  In the modified embodiment described above, it is particularly preferable that the markers M1 and M2 are arranged at substantially the same height position. Further, it is particularly preferable that the optical axis AR / AL is substantially parallel to the road surface in the marker group photographing section Tab in a side view. This is because the theoretical value calculator 32 can easily calculate the distance Db.

  In the modified embodiment described above, it is particularly preferable that the cameras 11R / 11L are arranged at substantially the same height as the markers M1 and M2. According to this, the point QR ′ coincides with the point QR, and the distance Da is equal to the distance D. Therefore, the theoretical value calculation unit 32 can directly acquire the distance D using the relational expression (2), and can omit the calculation of the distance Db.

  (2) In the above-described embodiment, the theoretical value calculator 32 calculates the parallax theoretical value Ft based on the adjustment image ER, but is not limited thereto. For example, the theoretical value calculation unit 32 may calculate the theoretical value Ft of parallax based on the adjustment image EL. Even when the adjustment image EL is used, the theoretical parallax value Ft can be suitably calculated. Further, for example, the theoretical value calculator 32 may calculate the theoretical value FtR of parallax based on the adjustment image ER, and may calculate the theoretical value FtL of parallax based on the adjustment image EL. In this case, the theoretical value calculation unit 32 may further calculate one parallax theoretical value Ft based on the parallax theoretical values FtR and FtL. According to this, the theoretical value Ft of parallax can be calculated with higher accuracy.

  (3) In the above-described embodiment, the measurement unit 31 acquires the parallax measurement value Fm related to one of the markers M1 and M2 based on one set of projection points mR and mL that are in a correspondence relationship. Not limited. For example, the measurement unit 31 may acquire the parallax measurement value Fm for both the markers M1 and M2 based on the two sets of projection points mR and mL that are in a correspondence relationship. In this case, the measurement unit 31 may further calculate one parallax measurement value Fm based on the parallax measurement value Fm related to the marker M1 and the parallax measurement value Fm related to the marker M2. According to this, the parallax measurement value Fm can be calculated with higher accuracy.

  (4) In the above-described embodiment, the horizontal adjustment amount calculation unit 33 determines the horizontal adjustment amount Hh so that the parallax measurement value Fm is equal to the parallax theoretical value Ft, but is not limited thereto. . For example, the horizontal adjustment amount calculation unit 33 may determine the horizontal adjustment amount Hh so that the difference between the parallax measurement value Fm and the parallax theoretical value Ft is small. Also in this modified embodiment, the lateral shift amount Bh can be adjusted suitably.

  Similarly, the vertical adjustment amount calculation unit 36 determines the vertical adjustment amount Hv so that the position of the projection point mR in the vertical direction is equal to the position of the projection point mL corresponding to the projection point mR in the vertical direction. However, it is not limited to this. For example, the vertical adjustment amount calculation unit 36 sets the vertical adjustment amount Hv so that the difference between the vertical position of the projection point mR and the vertical position of the projection point mL corresponding to the projection point mR is small. You may decide. Also according to this modified embodiment, the vertical shift amount Bv can be suitably adjusted.

  The rotation direction adjustment amount calculation unit 38 determines the rotation direction adjustment amount Hr so that the inclination of the virtual line KR and the inclination of the virtual line KL are equal, but the present invention is not limited to this. For example, the rotation direction adjustment amount calculation unit 38 may determine the rotation direction adjustment amount Hr so that the difference between the inclination of the virtual line KR and the inclination of the virtual line KL is small. Also according to this modified embodiment, the rotation amount Br can be suitably adjusted.

  (5) In the embodiment described above, the horizontal shift amount adjustment unit 27 changes the horizontal shift amount Bh whenever the adjustment images ER and EL are specified, but the present invention is not limited to this. For example, the lateral shift amount adjustment unit 27 may selectively change the lateral shift amount Bh according to the value of the lateral direction adjustment amount Hh. Similarly, in the above-described embodiment, the vertical shift amount adjustment unit 28 changes the vertical shift amount Bv whenever the adjustment images ER and EL are specified. However, the present invention is not limited to this. For example, the vertical shift amount adjustment unit 28 may selectively change the vertical shift amount Bv according to the value of the vertical direction adjustment amount Hv. In the above-described embodiment, the rotation amount adjustment unit 29 changes the rotation amount Br whenever the adjustment images ER and EL are specified. However, the present invention is not limited to this. For example, the rotation amount adjustment unit 29 may selectively change the rotation amount Br according to the value of the rotation direction adjustment amount Hr.

  Please refer to FIG. FIG. 11 is a block diagram illustrating a configuration of an imaging apparatus according to a modified embodiment. The same components as those in the above-described embodiment are denoted by the same reference numerals and detailed description thereof is omitted.

  The lateral shift amount adjustment unit 27 further includes a lateral direction adjustment amount determination unit 41. The horizontal direction adjustment amount determination unit 41 determines whether or not the horizontal direction adjustment amount Hh is equal to or greater than a predetermined threshold value. When it is determined that the horizontal adjustment amount Hh is equal to or greater than the predetermined threshold, the horizontal shift amount changing unit 34 changes the horizontal shift amount Bh. Otherwise, the horizontal shift amount changing unit 34 does not change the horizontal shift amount Bh.

  Similarly, the vertical shift amount adjustment unit 28 further includes a vertical direction adjustment amount determination unit 42. The vertical adjustment amount determination unit 42 determines whether or not the vertical adjustment amount Hv is greater than or equal to a predetermined threshold value. When it is determined that the vertical adjustment amount Hv is equal to or greater than the predetermined threshold, the vertical shift amount changing unit 37 changes the vertical shift amount Bv. Otherwise, the vertical shift amount changing unit 37 does not change the vertical shift amount Bv.

  The rotation amount adjustment unit 29 further includes a rotation direction adjustment amount determination unit 43. The rotation direction adjustment amount determination unit 43 determines whether or not the rotation direction adjustment amount Hr is greater than or equal to a predetermined threshold value. When it is determined that the rotation direction adjustment amount Hr is equal to or greater than the predetermined threshold value, the rotation amount changing unit 39 changes the rotation amount Br. Otherwise, the rotation amount changing unit 39 does not change the rotation amount Br.

  In this modified embodiment, the correction parameters Bh, Bv, Br are individually changed. That is, as a result, all of the correction parameters Bh, Bv, Br may be changed, some of the correction parameters Bh, Bv, Br may be changed, and any of the correction parameters Bh, Bv, Br May not be changed.

  According to this modified embodiment, it is possible to suitably prevent the lateral shift amount Bh from fluctuating excessively. As a result, the image correction unit 22 can correct the image IL more appropriately. Similarly, it is possible to suitably prevent the vertical shift amount Bv and the rotation amount Br from fluctuating excessively. As a result, the image correction unit 22 can further appropriately correct the image IL.

  (6) In the above-described embodiment, the image correction unit 22 corrects one of the images IR and IL, but is not limited thereto. For example, both the images IR and IL may be corrected. In this case, as shown in FIG. 11, the correction parameter storage unit 21 may store correction parameters BhR, BvR, BrR for the image IR and correction parameters BhL, BvL, BrL for the image IL. According to this, the image correction part 22 can correct | amend image IR, IL suitably, respectively.

  In this modified embodiment, the lateral shift amount adjustment unit 27 may adjust the lateral shift amount BhR for the image IR and the lateral shift amount BhL for the image IL, respectively. Similarly, the vertical shift amount adjustment unit 28 may adjust the vertical shift amounts BvR and BvL, respectively. The rotation amount adjustment unit 29 may adjust the rotation amounts BrR and BrL, respectively.

  (7) In the above-described embodiment, the image correction unit 22 performs the process of moving the image IL, but is not limited thereto. For example, the image correction unit 22 may correct image distortion in addition to the process of moving the image IL. According to this, the image IL can be corrected more suitably.

  (8) In the embodiment described above, the adjustment image ER is the image IR that has not been corrected by the image correction unit 22, and the adjustment image EL is the image ILc that has been corrected by the image correction unit 22. Not limited. For example, the adjustment image ER may be an image that has been corrected by the image correction unit 22, and the adjustment image EL may be an image that has not been corrected by the image correction unit 22. In the above-described embodiment, one of the adjustment images ER and EL is the image ILc corrected by the image correction unit 22, but is not limited thereto. For example, both of the adjustment images ER and EL may be images corrected by the image correction unit 22. Also by this, the horizontal shift amount adjustment unit 27, the vertical shift amount adjustment unit 28, and the rotation amount adjustment unit 29 can suitably adjust the correction parameters Bh, Bv, and Br, respectively.

  Further, for example, both the adjustment images ER and EL may be images that have not been corrected by the image correction unit 22. Specifically, as illustrated in FIG. 11, the adjustment image specifying unit 25 may determine whether the images IR and IL are the adjustment images ER and EL. In this modified embodiment, it is preferable that the lateral shift amount changing unit 34 sets the lateral adjustment amount Hh as a new lateral shift amount Bh. Accordingly, the horizontal adjustment amount Hh is stored in the correction parameter storage unit 21 as a new horizontal shift amount Bh. Similarly, it is preferable that the vertical shift amount changing unit 37 sets the vertical adjustment amount Hv as a new vertical shift amount Bv. The rotation amount changing unit 39 preferably sets the rotation direction adjustment amount Hr as a new rotation amount Br. According to this, when both the adjustment images ER and EL are uncorrected images, the correction parameters Bh, Bv, and Br can be suitably adjusted.

  Furthermore, in this modified embodiment, when it is determined that the images IR and IL are the adjustment images ER and EL, the adjustment units 27 to 29 perform correction parameters Bh, Bv, The images IR and IL determined to be the adjustment images ER and EL may be corrected by changing Br and using the corrected correction parameters Bh, Bv, and Br by the image correction unit 22. According to this, the image re-correction unit 24 described in the embodiment can be omitted.

  (9) In the above-described embodiment, the determination conditions 1 to 4 used by the adjustment image specifying unit 25 are exemplified, but the determination conditions can be appropriately designed and selected.

For example, the adjustment image specifying unit 25 may use the following determination condition 5 in addition to the determination conditions 1 to 4.
Determination condition 5: The difference between the difference ΔvR and the difference ΔvL is equal to or less than the threshold value.
Here, the difference ΔvR is defined in the determination condition 2, and the difference ΔvL is defined in the determination condition 4.

The adjustment image specifying unit 25 may use determination conditions 6 to 9 shown below.
Determination condition 6: The number of projection points mR of the image IR is two.
Determination condition 7: One projection point mR1 is in the region WR1 of the image IR, and the other projection point mR2 is in the region WR2 of the image IR.
Judgment condition 8: The number of projection points mL of the image IL is two.
Determination condition 9: One projection point mL1 is in the region WL1 of the image IL, and the other projection point mL2 is in the region WL2 of the image IL.

  Here, each of the regions WR1 and WR2 is defined by the coordinate value of the horizontal axis uR and the coordinate value of the vertical axis vR. Similarly, each of WL1 and WL2 is defined by a coordinate value on the horizontal axis uL and a coordinate value on the vertical axis vL. Also according to such a modified embodiment, the adjustment image specifying unit 25 can preferably determine whether the images IR and ILc are the adjustment images ER and EL.

  (10) In the above-described embodiment, the horizontal shift amount adjustment unit 27, the vertical shift amount adjustment unit 28, and the rotation amount adjustment unit 29 are provided. However, the present invention is not limited to this. For example, any one or two of the adjustment units 27 to 29 may be omitted. Also in this modified example, when the vehicle 1 is actually operating, the image processing unit 13 can suitably adjust at least one of the correction parameters Bh, Bv, and Br.

  (11) In the above-described embodiment, the photographing apparatus 5 includes the two cameras 11R and 11L, but is not limited thereto. For example, the imaging device 5 may include three or more cameras 11. That is, a stereo camera may be configured by three or more cameras 11.

  (12) In the above-described embodiments, the optical axes AR and AL are parallel to the front direction Zf, but the present invention is not limited to this. That is, the optical axes AR and AL may not be parallel to the front direction Zf.

  (13) In the above-described embodiment, the marker group MG includes the two markers M1 and M2. However, the present invention is not limited to this. The marker group MG may include three or more markers M. In this modified embodiment, the marker M may be arranged at an appropriate position. For example, three or more markers M may be arranged on the plane P described in the embodiment. Further, for example, two or more markers M may be arranged on the plane P, and another marker M may be arranged at a position off the plane P. According to this, the horizontal adjustment amount Hh, the vertical adjustment amount Hv, and the rotation direction adjustment amount Hr can be calculated more appropriately.

  (14) In the embodiment described above, the vehicle 1 is a golf cart, but is not limited thereto. The vehicle 1 may be applied to various uses. For example, the vehicle 1 may be a vehicle for traveling in a farm. The vehicle 1 may be an unmanned traveling vehicle.

  (15) In the above-described embodiment, the marker M1 and the marker M2 are arranged at substantially the same height, but the present invention is not limited to this. For example, the height position of at least one of the markers M1 and M2 may be arbitrarily changed.

  (16) The above-described embodiments and the modified embodiments described in the above (1) to (15) may be appropriately changed by replacing or combining each configuration with the configuration of another modified embodiment. Good.

DESCRIPTION OF SYMBOLS 1 ... Vehicle 11R, 11L ... Camera (image sensor)
DESCRIPTION OF SYMBOLS 5 ... Imaging device 13 ... Image processing part 21 ... Correction parameter storage part 22 ... Image correction part 23 ... Image storage part 24 ... Image re-correction part 25 ... Adjustment image specific part 26 ... Shooting condition storage part 27 ... Horizontal shift amount adjustment Section 28 ... Vertical shift amount adjustment section 29 ... Rotation amount adjustment section 31 ... Measurement section 32 ... Theoretical value calculation section 33 ... Horizontal adjustment amount calculation section 34 ... Horizontal shift amount change section AR, AL ... Optical axis Bh ... Horizontal shift amount Bv… Vertical shift amount Br… Rotation amount D… Distance ER, EL… Adjustment image Fm… Parallax measurement value Ft… Parallax theoretical value Hh… Lateral adjustment amount Hv… Vertical adjustment amount Hr… Rotation direction adjustment amount IR , IL, ILc ... image LM ... marker interval Lm ... projection point interval MG ... marker group M1, M2 ... marker (first marker, second marker)
mR1, mR2, mL1, mL2 ... Projection point P ... Plane T ... Runway

Claims (11)

A photographing device,
The imaging device
A pair of image sensors;
An image correction unit that translates an image captured by at least one of the image sensors in the lateral direction of the image by a lateral shift amount;
Images obtained by photographing the first marker and the second marker at positions where the distance from the first marker in the optical axis direction is substantially equal to the distance from the second marker in the optical axis direction. A horizontal shift amount adjustment unit that adjusts the horizontal shift amount based on the adjustment image,
With
The lateral shift amount adjustment unit
A measurement unit that measures parallax related to at least one of the first marker and the second marker based on both of the adjustment images, and obtains a parallax measurement value;
A theoretical value calculation unit that calculates a theoretical value of parallax related to the first marker and the second marker based on an interval between the first marker and the second marker and either one of the adjustment images. When,
A lateral adjustment amount calculation unit for calculating a lateral adjustment amount based on the parallax measurement value and the parallax theoretical value;
A lateral shift amount changing unit that changes the lateral shift amount using the lateral adjustment amount;
With
At least one of the adjustment images is an image that has been processed by the image correction unit,
The horizontal shift amount changing unit adds or subtracts the horizontal adjustment amount to the horizontal shift amount used by the image correction unit,
The imaging device may further include, when the horizontal shift amount is changed by the horizontal shift amount changing unit, using the changed horizontal shift amount, the original image of the adjustment image that has been processed by the image correcting unit. comprising an image re-correcting unit for re-correcting an image to be,
The theoretical value calculation unit includes the interval between the first marker and the second marker, an optical center associated with any of the adjustment images, and a projection point of the first marker on the adjustment image. And the distance in the optical axis direction between the first marker and the second marker and the image sensor based on the interior angle of the triangle having the projection point of the second marker on the adjustment image as a vertex. And a parallax theoretical value based on the distance. The imaging device according to claim 1,
The theoretical value calculator is based on the positional relationship between the image sensor, the first marker, and the second marker in the optical axis direction between the first marker, the second marker, and the image sensor. An imaging apparatus that calculates a distance and calculates a theoretical value of the parallax based on the distance. In the imaging device according to claim 1 or 2,
The lateral adjustment amount calculation unit is an imaging device that determines the lateral adjustment amount so that a difference between the measured value of parallax and the theoretical value of parallax becomes small. In the imaging device according to any one of claims 1 to 3,
The imaging device further determines whether the image obtained from each of the image sensors is an adjustment image based on the projection point of the first marker and the projection point of the second marker on the image. An image capturing apparatus including an adjustment image specifying unit. In the imaging device according to any one of claims 1 to 4,
The imaging device in which the first marker and the second marker are arranged at substantially the same height position. In the imaging device according to any one of claims 1 to 5,
The image correction unit further translates an image captured by at least one of the image sensors in the vertical direction of the image by a vertical shift amount,
The photographing apparatus further includes a vertical shift amount adjustment unit that adjusts the vertical shift amount based on the adjustment image. In the imaging device according to any one of claims 1 to 6,
The image correction unit further rotates an image captured by at least one of the image sensors by a rotation amount,
The imaging apparatus further includes a rotation amount adjustment unit that adjusts the rotation amount based on the adjustment image. A vehicle,
The vehicle includes a photographing device,
The imaging device
A pair of image sensors;
An image correction unit that translates an image captured by at least one of the image sensors in the lateral direction of the image by a lateral shift amount;
Images obtained by photographing the first marker and the second marker at positions where the distance from the first marker in the optical axis direction is substantially equal to the distance from the second marker in the optical axis direction. A horizontal shift amount adjustment unit that adjusts the horizontal shift amount based on the adjustment image,
With
The lateral shift amount adjustment unit
A measurement unit that measures parallax related to at least one of the first marker and the second marker based on both of the adjustment images, and obtains a parallax measurement value;
A theoretical value calculation unit that calculates a theoretical value of parallax related to the first marker and the second marker based on an interval between the first marker and the second marker and either one of the adjustment images. When,
A lateral adjustment amount calculation unit for calculating a lateral adjustment amount based on the parallax measurement value and the parallax theoretical value;
A lateral shift amount changing unit that changes the lateral shift amount using the lateral adjustment amount;
With
The first marker and the second marker are installed outside the vehicle,
The first marker and the second marker are arranged so as to sandwich a runway,
When the vehicle travels on the road, the image sensors respectively capture the first marker and the second marker. The vehicle according to claim 8, wherein
The runway is predetermined,
The vehicle is a vehicle that autonomously travels on the road. When the vehicle is running, a process in which a plurality of image sensors mounted on the vehicle capture a marker group installed outside the vehicle;
Correcting an image obtained from at least one of the image sensors;
Adjusting the correction parameter used in the process of correcting the image based on the adjustment image, using the image obtained from the image sensor and projecting the marker group as the adjustment image;
With
The marker group includes a first marker and a second marker,
The first marker and the second marker are arranged so as to sandwich a straight runway ,
The correction parameter is a lateral shift amount,
The process of correcting the image includes translating the image in the horizontal direction of the image by the horizontal shift amount,
The first marker and the second marker are spaced apart from each other;
When performing the photographing process, the distance in the optical axis direction between the image sensor and the first marker and the distance in the optical axis direction between the image sensor and the second marker are substantially equal,
The process of adjusting the correction parameter includes:
A process of measuring a parallax regarding at least one of the first marker and the second marker based on both of the adjustment images, and obtaining a parallax measurement value;
Calculating a theoretical value of parallax related to the first marker and the second marker based on the interval between the first marker and the second marker and either one of the adjustment images;
Calculating a lateral adjustment amount based on the measured value of the parallax and the theoretical value of the parallax;
Changing the lateral shift amount using the lateral adjustment amount;
An image correction method comprising:   When the vehicle is running, a process in which a plurality of image sensors mounted on the vehicle capture a marker group installed outside the vehicle;
  Correcting an image obtained from at least one of the image sensors;
  Adjusting the correction parameter used in the process of correcting the image based on the adjustment image, using the image obtained from the image sensor and projecting the marker group as the adjustment image;
  With
  The marker group includes a first marker and a second marker,
  The first marker and the second marker are arranged so as to sandwich a straight runway,
  The plurality of image sensors constitute a stereo camera,
  The correction parameter is a lateral shift amount,
  The process of correcting the image is an image correction method of translating the image in the horizontal direction of the image by the horizontal shift amount.

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