JP2007057933A - Camera having electronic view finder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera having an electronic view finder which does not give an unpleasant feeling to a photographer. <P>SOLUTION: A fixed pattern image is stored in a data holding circuit 70. When detecting dust in through-image display, a message is displayed, and the position of the image of the dust is detected from a difference between imaging data obtained by imaging in such a state where the camera 1 turns toward the sky and the fixed pattern image. The image of the dust is removed in a dust removing circuit 54a on the basis of the detected position. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a camera having an electronic viewfinder.

  There are various types of camera finders such as a transmission finder, a virtual image finder, and a real image finder. In the real image type finder, there is an advantage that the focusing state of the photographing lens can be visually recognized if a focusing screen (focusing screen) is arranged on the focal plane. Here, in the real image type viewfinder in the conventional single-lens reflex camera, the optical path is bent upward by a movable mirror disposed in the photographing optical path to form a left-right inverted image on the focusing screen, and this image is converted to a pentaprism. Thus, an erect image is formed through the eyepiece, and optical observation is possible through the eyepiece.

  Also, a so-called electronic viewfinder mechanism in which an image pickup device for picking up an image formed on the focusing screen is arranged in the observation optical path, and an image acquired by the image pickup device is displayed on a liquid crystal monitor or the like arranged on the back of the camera. Many single-lens reflex cameras having a through image display mechanism and a live view mechanism have also been proposed, for example, Patent Document 1 and Patent Document 2.

According to such an electronic viewfinder mechanism, the photographer can check the subject image without looking into the viewfinder eyepiece, and the subject image can be confirmed by increasing the size of the display device such as a liquid crystal monitor. There is an advantage that it becomes easy to do.
JP 7-287160 A JP 2001-296484 A

  By the way, since the surface of the focusing screen is a matte surface so that the degree of blur in the subject image can be visually recognized, dust tends to adhere to the surface. When dust adheres to the focusing screen, the observation image is unsightly even with an optical viewfinder, but in the case of an electronic viewfinder, the dust image is enlarged and displayed together with the subject image. Therefore, it becomes more unsightly and is likely to make the photographer feel uncomfortable.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a camera having an electronic viewfinder that does not give a photographer an unpleasant feeling.

  In order to achieve the above object, a camera having an electronic viewfinder according to the first aspect of the present invention images a subject image on a focusing screen and displays imaging data acquired by the imaging as an electronic viewfinder display image. In a camera having an electronic viewfinder, a low-contrast means for forming a low-contrast image on the focusing screen, and imaging data obtained by imaging the low-contrast image formed on the focusing screen And a dust detecting means for detecting the position of the dust attached to the focusing screen, and a dust removing means for removing the dust image from the electronic viewfinder display image according to the detection result of the dust detecting means. It is characterized by that.

  In the first aspect, the position of the dust is detected by the dust detection means in a state where a low-contrast image is formed on the focusing screen, and the image of the dust in the electronic viewfinder display image is removed based on this position. be able to.

  According to the present invention, it is possible to provide a camera having an electronic viewfinder that does not give an unpleasant feeling to a photographer.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is an external rear perspective view of a digital camera having an electronic viewfinder according to the first embodiment of the present invention. A digital camera (hereinafter referred to as a camera) 1 in FIG. 1 shows a single-lens reflex digital camera with interchangeable lenses as an example. The camera 1 is mainly composed of a lens barrel 10 as an interchangeable lens and a camera body 20, and a desired lens barrel 10 is set to be detachable with respect to the front surface of the camera body 20. .

  In FIG. 1, a release button 21, a mode dial 22, a power switch lever 23, a control dial 24, and the like are provided on the upper surface of the camera body 20.

  The release button 21 is a button for executing an exposure preparation operation and an exposure operation. The release button 21 is composed of a two-stage switch of a 1st release switch and a 2nd release switch. When the release button 21 is pressed halfway, the 1st release switch is turned on to perform photometry processing or distance measurement processing. An exposure preparation operation such as is performed. Further, when the release button 21 is fully pressed, the 2nd release switch is turned on and the exposure operation is executed.

  The mode dial 22 is an operation member for setting a shooting mode at the time of shooting. When the mode dial 22 is rotated in a predetermined direction, a shooting mode at the time of shooting is set. The power switch lever 23 is an operation member for turning on / off the power of the camera 1. By turning the power switch lever 23, the main power supply of the camera 1 is switched on / off.

  The control dial 24 is a member for setting shooting information. By operating the control dial 24, various settings are performed during shooting.

  In FIG. 1, a liquid crystal monitor 25, a playback button 26, a cross key 27, an OK button 28, a cleaning button 29, and the like are disposed on the back of the camera body 20.

  The liquid crystal monitor 25 is a monitor for displaying captured images, menus, and the like. The playback button 26 is a button for switching the operation mode of the camera 1 to a playback mode for image playback. The cross key 27 is an operation key for selecting each item on a menu screen or the like. The OK button 28 is an operation member for determining the selected item. The cleaning button 29 is a button for executing a dust detection process for causing the camera to detect a dust image in an image displayed during a through image display described later.

  FIG. 2 is a perspective view showing the configuration of the optical system inside the camera body in the first embodiment of the present invention.

  This optical system includes a first reflection mirror 31, a focusing screen (also referred to as a screen mat) 32, and a plurality of mirrors (second reflection mirror 33, third reflection mirror 34, and fourth reflection mirror 35 shown in FIG. 2). And an eyepiece lens 36.

  The first reflecting mirror 31 is configured to be rotatable in the direction of the arrow A in the figure about a shaft 31a. The first reflecting mirror 31 is in the position shown in FIG. 2 when observing the subject, and the light beam that has passed through the photographing lens 11 in the lens barrel 10 is in an angular direction of approximately 90 ° with respect to the optical axis of the photographing lens 11. The light is reflected in the direction of a certain second reflecting mirror 33, that is, in the right direction when viewed from the lens barrel 10 side of the camera body 20. The first reflecting mirror 31 is partially composed of a half mirror. The first reflecting mirror 31 transmits the light beam incident from the photographing lens 11 through the half mirror part and enters the distance measuring circuit described later. On the other hand, the first reflecting mirror 31 is retracted from the photographing optical path so that the light beam from the subject is guided to a recording imaging element (details will be described later) disposed behind the first reflecting mirror 31 during imaging.

  The light beam reflected by the reflecting surface of the first reflecting mirror 31 is imaged on a focusing screen 32 disposed between the first reflecting mirror 31 and the second reflecting mirror 33. The focusing screen 32 has a diffusing surface for diffusing the light beam in order to form the light beam reflected by the first reflecting mirror 31 as an optical image. It is arranged at a position equivalent to. The focusing screen 32 is formed with a distance measuring frame 32a for allowing the photographer to check the distance measuring range.

  The light beam that has passed through the focusing screen 32 enters the second reflection mirror 33. The second reflection mirror 33 is disposed on the reflection optical axis from the first reflection mirror 31, and the reflection surface thereof is inclined with respect to the reflection optical axis of the first reflection mirror 31 by a predetermined angle. A part of the reflected light beam from the first reflection mirror 31 incident on the second reflection mirror 33 is at an angle of about 90 ° with respect to the reflection optical axis from the first reflection mirror 31, that is, above the camera body 20. Reflected towards.

  The light beam reflected by the reflecting surface of the second reflecting mirror 33 is on the reflecting optical axis of the reflecting surface of the second reflecting mirror 33, and the reflecting surface is relative to the reflecting optical axis of the reflecting surface of the second reflecting mirror 33. The light enters the third reflection mirror 34 that is inclined at a predetermined angle. The reflected light beam from the second reflecting mirror 33 incident on the third reflecting mirror 34 is approximately 90 ° at the reflecting surface of the third reflecting mirror 34 with respect to the reflected optical axis from the reflecting surface of the second reflecting mirror 33. The angle is reflected toward the direction opposite to the reflection direction by the reflection surface of the first reflection mirror 31, that is, toward the left direction of the camera body 20.

  The light beam reflected by the reflecting surface of the third reflecting mirror 34 is on the reflecting optical axis of the reflecting surface of the third reflecting mirror 34, and the reflecting surface is relative to the reflecting optical axis of the reflecting surface of the third reflecting mirror 34. The light enters the fourth reflection mirror 35 that is inclined at a predetermined angle. A part of the reflected light beam from the third reflection mirror 34 incident on the fourth reflection mirror 35 is approximately 90 with respect to the reflection optical axis from the third reflection mirror 34 on the reflection surface of the fourth reflection mirror 35. Reflected at an angle of °. Thereby, the reflected light beam from the reflecting surface of the third reflecting mirror 34 is incident on the eyepiece 36 disposed on the reflecting optical axis of the reflecting surface of the fourth reflecting mirror 35. The subject image formed on the focusing screen 32 in this way is inverted so as to be an erect image and guided to the eyepiece 36. Thus, the subject image formed on the focusing screen 32 by the photographer's eye 37 can be observed through the eyepiece 36.

  Here, the second reflection mirror 33 and the fourth reflection mirror 35 are configured as half mirrors, and a photometric element 38 for measuring the brightness of the subject is disposed on the back side of the reflection surface of the second reflection mirror 33. Has been. Further, an imaging lens 39 and a through-image imaging device 40 are disposed on the back surface side of the reflecting surface of the fourth reflecting mirror 35. The through-image imaging element 40 is a photoelectric conversion element for acquiring an image of a subject imaged on the focusing screen 32 via the imaging lens 39. Although the image of the subject formed on the through image pickup device 40 is inverted by 180 ° with respect to the actual subject image, the same angle of view as the image seen by the photographer's eye 37 through the eyepiece 36 is used. Is obtained. Thus, the image obtained by the through-image image sensor 40 is read out in an appropriate order by an image sensor driving circuit described later, and then displayed as an image on the liquid crystal monitor 25, for example. If such display is continuously performed, an image similar to the image that can be seen by the photographer can be displayed on the liquid crystal monitor 25 or the like via the eyepiece 36. Such a display method is called live view display or live view display. With such a configuration, an electronic viewfinder is configured.

  In the example of FIG. 2, the first reflecting mirror 31, the second reflecting mirror 33, the third reflecting mirror 34, and the fourth reflecting mirror 35 are arranged so as to reflect the incident light beam at an angle of approximately 90 °. However, it is not limited to this.

  FIG. 3 is a block diagram for explaining an electric circuit configuration of the camera having the electronic viewfinder according to the first embodiment of the present invention. In FIG. 3, the same components as those described in FIG. 1 or FIG.

  The lens barrel 10 is provided with a photographic lens 11, a lens driving circuit 12, a diaphragm 13, a diaphragm driving mechanism 14, and a lens CPU 15 shown in FIG. The photographing lens 11 is composed of a plurality of lenses such as a focus lens and a zoom lens, and makes an image of a subject (subject image) (not shown) incident in the direction inside the camera body 20. The lens driving circuit 12 performs focus adjustment driving and variable power driving of the photographing lens 11 under the control of the lens CPU 15. The diaphragm 13 adjusts the amount of light of the subject image that enters the camera body 20. The aperture drive mechanism 14 opens and closes the aperture 13 under the control of the lens CPU 15. The lens CPU 15 controls each part in the lens barrel 10 such as control of the lens driving circuit 12 and control of the aperture driving mechanism 14. Further, the lens CPU 15 is configured to be able to communicate with the camera control circuit 50 in the camera body 20.

  Further, in the camera body 20, the optical system (the first reflection mirror 31, the focusing screen 32, the second reflection mirror 33, the third reflection mirror 34, the fourth reflection mirror 35, and the eyepiece 36) described in FIG. 2 is provided. Is provided. When the first reflecting mirror 31 is located on the optical axis of the photographing lens 11 shown in FIG. 3, the subject image that has passed through the photographing lens 11 is the second reflecting mirror 33, the third reflecting mirror 34, and the fourth reflecting mirror. The light enters the eyepiece lens 36, the photometric element 38, and the live view image sensor 40 through the reflection mirror 35. Here, the driving of the first reflecting mirror 31 is performed by the mirror driving mechanism 42.

  The eyepiece lens 36 is provided in the vicinity of the fourth reflection mirror 35 and adjusts so that the photographer can easily observe the subject image. The photometric element 38 is provided in the vicinity of the second reflecting mirror 33 and outputs a signal corresponding to the amount of light flux based on the subject image to the camera control circuit 50. The through-image imaging element 40 performs an imaging operation for converting the subject image transmitted through the fourth reflection mirror 35 into an electrical signal. The image sensor drive circuit 49 reads out an image signal obtained by the imaging operation in the through image sensor 40 and outputs it to the camera control circuit 50.

  Further, a partial region of the first reflecting mirror 31 is a half mirror, and a sub mirror 43 is provided on the back surface thereof. The sub mirror 43 reflects the subject image transmitted through the half mirror area of the first reflecting mirror 31 in the direction of the distance measuring circuit 44. The distance measuring circuit 44 includes a distance measuring optical system, a distance measuring sensor, and the like. The object image reflected by the sub-mirror 43 is received by the distance measuring sensor through the distance measuring optical system, and the received light flux. Is output to the camera control circuit 50.

  Further, a shutter 45 is disposed behind the first reflection mirror 31. The shutter 45 is a focal plane type shutter composed of, for example, a front curtain and a rear curtain. The subject image on the imaging surface is obtained by shielding or exposing the imaging surface of the recording image sensor 47 disposed on the rear side. Adjust the amount of incident light. The shutter drive mechanism 46 opens and closes the shutter 45 under the control of the camera control circuit 50.

  The recording image sensor 47 performs an imaging operation for converting a subject image incident through the shutter 45 into an electrical signal. The image sensor driving circuit 48 reads out an image signal obtained by the imaging operation in the recording image sensor 47 and outputs the image signal to the camera control circuit 50.

  Next, the camera control circuit 50 will be described. The camera control circuit 50 is an IC circuit configured so that various processes in the camera body 20 can be executed in an integrated manner.

  First, a sequence controller 51 is provided in the camera control circuit 50. The sequence controller 51 controls each circuit in the camera control circuit 50 and performs various calculations such as a photometry calculation and a distance measurement calculation described later.

  The bus 52 is a transfer path for transferring various processing data in the camera control circuit 50 to each unit in the camera control circuit 50. In addition to the sequence controller 51, the bus 52 includes a communication circuit 53, a through image processing circuit 54, an input / output circuit 56, a recording image processing circuit 57, an SDRAM control circuit 59, a compression circuit 61, a recording medium control circuit 62, a video signal. An output circuit 64, a FLASHROM control circuit 66, a switch detection circuit 68, a data holding circuit 70, and a display data storage circuit 71 are connected.

  The communication circuit 53 is a communication interface circuit for performing communication between the camera control circuit 50 and the lens CPU 15 in the lens barrel 10.

  An image sensor interface circuit 55 is connected to the through image processing circuit 54. The image sensor interface circuit 55 performs analog processing such as noise removal, amplification, and waveform shaping on the image signal read from the through image sensor 40 via the image sensor drive circuit 49, and then performs these processes. The applied analog image signal is converted into a digital signal to generate imaging data, and the imaging data is output to the through image processing circuit 54. The through image processing circuit 54 performs various image processing for displaying a through image, such as resizing processing, on the imaging data generated in the imaging element interface circuit 55. The through image processing circuit 54 includes a dust removal circuit 54a that functions as dust detection means and dust removal means. The operation of the dust removal circuit 54a will be described later.

  The input / output circuit 56 transmits and receives signals between the camera control circuit 50 and the photometric element 38, the mirror drive mechanism 42, the distance measurement circuit 44, and the shutter drive mechanism 46 provided outside the camera control circuit 50. It is an interface circuit for performing.

  An image sensor interface circuit 58 is connected to the recorded image processing circuit 57. The image sensor interface circuit 58 performs analog processing such as noise removal, amplification, and waveform shaping on the image signal read from the recording image sensor 47 via the image sensor drive circuit 48, and then performs these processes. The analog image signal thus converted is converted into a digital signal to generate imaging data, and this imaging data is output to the recorded image processing circuit 57. The recorded image processing circuit 57 performs various image processing for image recording, such as white balance correction, γ correction, and color correction, on the imaging data generated by the imaging element interface circuit 58.

  The SDRAM control circuit 59 performs control of a write address when writing data to the SDRAM 60, control of a read address when reading data from the SDRAM 60, and the like. The SDRAM 60 temporarily stores various data such as the image data processed by the through image processing circuit 54 and the recorded image processing circuit 57 and the output of the photometric element 38 and the output of the distance measuring circuit 44 input via the input / output circuit 56. To do.

  The compression circuit 61 compresses the image data processed by the recorded image processing circuit 57 using a method such as the JPEG method, or decompresses the compressed image data. The recording medium control circuit 62 performs control of a write address when writing the imaging data compressed by the compression circuit 61 to the recording medium 63 and control of a read address when reading compressed data from the recording medium 63. The recording medium 63 is, for example, a memory card that can be freely attached to and detached from the camera body 20, and the imaging data compressed by the compression circuit 61 is recorded on the recording medium 63.

  The video signal output circuit 64 converts the imaging data processed by the recorded image processing circuit 57 or the imaging data processed by the through image processing circuit 54 into a signal suitable for display and outputs the signal to the liquid crystal monitor drive circuit 65. The liquid crystal monitor drive circuit 65 displays an image on the liquid crystal monitor 25 based on the signal input from the video signal output circuit 64.

  The FLASHROM control circuit 66 performs control of a write address when writing data to the FLASHROM 67, control of a read address when reading data from the FLASHROM 67, and the like. The FLASH ROM 67 stores various programs executed by the sequence controller 51 and various adjustment values related to the camera body 20.

  The switch detection circuit 68 is operated by operating operation members such as the release button 21, the mode dial 22, the power switch lever 23, the control dial 24, the playback button 26, the cross key 27, the OK button 28, and the cleaning button 29 described with reference to FIG. The on / off state of each SW 69 to be turned on / off is detected, and a signal corresponding to the state is output.

  The data holding circuit 70 stores a fixed pattern image used in dust removal processing described later. This fixed pattern image will be described later. The display data storage circuit 71 stores message data for displaying a message during dust detection processing described later.

  Next, a through image display operation in the camera having the above configuration will be described. FIG. 4 is a flowchart showing the processing of the sequence controller 51 during live view display. The sequence controller 51 controls to display a through image when the camera is turned on. First, the sequence controller 51 instructs the through image processing circuit 54 to start displaying a through image (step S1). After instructing the start of live view display, the sequence controller determines whether or not the 1st release switch is turned on (step S2).

  If it is determined in step S2 that the 1st release switch is not turned on, the through image display is continued. In this case, the process branches from step S2 to step S3, and the sequence controller 51 determines whether or not the cleaning button 29 is turned on (step S3). If it is determined in step S3 that the cleaning button 29 is on, the process branches from step S3 to step S4, and the sequence controller 51 displays a message as shown in FIG. An instruction is sent as follows (step S4). Here, the message in step S4 is a guide display for guiding the photographer to perform an operation for detecting dust. Data for displaying this message is stored in the display data storage circuit 71.

  After instructing the message display, the sequence controller 51 determines whether or not the OK button 28 is turned on by the photographer (step S5). Then, it waits until the OK button 28 is turned on.

  The photographer who has seen the message 81 as shown in FIG. 5 points the camera 1 to the sky and then presses the OK button 28. In response to this operation, the process branches from step S5 to step S6, and the sequence controller 51 sends an instruction to the lens CPU 15 via the communication circuit 53 to move the photographing lens 11 to the closest position (step S6). ). Here, the reason why the photographing lens 11 is moved to the closest position is to further reduce the contrast of the sky image captured as the subject.

  After giving an instruction to move the photographing lens 11 to the closest position in step S6, the sequence controller 51 sends an instruction to the through image processing circuit 54 to perform dust detection processing (step S7).

  In step S7, after sending an instruction to the through image processing circuit 54 to perform dust detection processing, the sequence controller 51 determines whether or not the cleaning button 29 has been turned on by the photographer (step S8). If it is determined in step S8 that the cleaning button 29 is turned on, the process returns to step S7, and an instruction is sent to the through image processing circuit 54 to perform the dust detection process again. The cleaning button 29 is turned on as needed by the photographer who has seen the message 83 shown in FIG.

  On the other hand, if it is determined in step S8 that the cleaning button 29 is not turned on, the process branches from step S8 to step S9, and the sequence controller 51 determines whether or not the OK button 28 is turned on by the photographer. Determine (step S9). The OK button 28 is turned on by the photographer who has seen the message 82 shown in FIG. If it is determined in step S9 that the OK button 28 is not turned on, the process returns to step S8. On the other hand, if it is determined in step S9 that the OK button 28 is turned on, the process branches from step S9 to step S10, and the sequence controller 51 ends the dust detection process for the through image processing circuit 54. (Step S10), and the process returns to Step S2.

  If it is determined in step S3 that the cleaning button 29 is not turned on, the process returns to step S2 without performing the processes in steps S4 to S10.

  Further, if the first release switch is turned on in the determination in step S2, the process branches from step S2 to step S11, and the sequence controller 51 performs recording imaging based on the output of the photometric element 38. The exposure amount (aperture value and shutter speed) is calculated (step S11), and the calculated aperture value is communicated to the lens CPU 15. After calculating the exposure amount, the sequence controller 51 calculates the defocus amount of the photographing lens 11 based on the output of the distance measuring circuit 44, and communicates this defocus amount to the lens CPU 15 (step S12). The lens CPU 15 calculates the driving amount of the lens necessary for the focus adjustment based on the received defocus amount, and performs the focus adjustment of the photographing lens 11 via the lens driving circuit 12 based on this.

  After the focus adjustment is completed in step S12, the sequence controller 51 determines whether or not the 2nd release switch is turned on (step S13). If it is determined in step S13 that the 2nd release switch is not turned on, the process branches from step S13 to step S14, and the sequence controller 51 determines whether or not the 1st release switch remains on. (Step S14). If it is determined in step S14 that the first release switch remains on, the process returns to step S13. On the other hand, if it is determined in step S14 that the 1st release switch is turned off, the process returns to step S2.

  If it is determined in step S13 that the 2nd release switch is turned on, the process branches from step S13 to step S15, and the sequence controller 51 instructs the through image processing circuit 54 to stop displaying the through image. Is performed (step S15). Thereafter, an exposure operation is performed. Note that the exposure operation may be performed using a well-known method, and thus description thereof is omitted.

  Next, the operation of the through image processing circuit 54 when displaying a through image will be described. FIG. 6 is a flowchart showing the operation of the through image processing circuit 54 when displaying a through image.

  The through image processing circuit 54 determines whether or not a through image display start instruction is sent from the sequence controller 51 (step S21), and waits until a through image display start instruction is sent. If it is determined in step S21 that a through image display start instruction is sent, the process branches from step S21 to step S22 to determine whether a dust detection instruction is sent from the sequence controller 51 (step S21). S22).

  If it is determined in step S22 that a dust detection instruction is sent from the sequence controller 51, the process branches from step S22 to step S23, and the through image processing circuit 54 is acquired by the through image sensor 40. The captured image data is captured as a dust detection image (step S23). Here, since the camera 1 is directed to the sky prior to the process of step S23, the dust detection image includes at least an empty image 91 and a distance measurement frame 32a as shown in FIG. An image 92 is captured. Further, if dust adheres to the focusing screen 32, a dust image 93 is also captured.

  Subsequently, the through image processing circuit 54 reads a fixed pattern image stored in the data holding circuit 70 in the camera control circuit 50 (step S24). This fixed pattern image is an image obtained when a predetermined low-contrast subject is imaged in a state where dust is not attached to the focusing screen 32 at the time of manufacturing the camera. The image obtained under such conditions is an image including only the distance measurement frame image 92 formed on the focusing screen 32 as a high-contrast subject. Here, examples of the predetermined low-contrast subject include the sky and a screen having a uniform luminance surface.

  Next, the through image processing circuit 54 takes the difference between the dust detection image and the fixed pattern image in step S23, thereby obtaining a distance measurement frame image 92 which is an image of the fixed pattern always included in the dust detection image. Erasing is performed (step S25). Then, the through image processing circuit 54 increases the contrast of the dust image portion (step S26). In this process, for example, a binarization process may be performed in which the image portion of dust is black and the other portion is white. By this high contrast processing, a dust confirmation image of only the dust image 93 as shown in FIG. 7B is generated.

  After generating the dust confirmation image in step S26, the through image processing circuit 54 displays the generated dust confirmation image on the liquid crystal monitor 25 (step S27). Thereafter, the through image processing circuit 54 determines whether or not the dust detection instruction is sent again from the sequence controller 51 (step S28). If it is determined in step S28 that a dust detection instruction has been sent, the process returns to step S23. This is processing when the photographer who has seen the message 83 shown in FIG. 5 presses the cleaning button 29.

  On the other hand, if it is determined in step S28 that no dust detection instruction has been sent, the process branches from step S28 to step S29, and the through image processing circuit 54 sends a dust detection end instruction from the sequence controller 51. It is determined whether it has been received (step S29). If it is determined in step S29 that no dust detection end instruction has been sent, the process returns to step S28.

  On the other hand, if a dust detection end instruction is sent in the determination in step S29 (when the OK button 28 is pressed by the photographer who has seen the message 82 shown in FIG. 5), the process proceeds from step S29 to step S29. After branching to S30, the through image processing circuit 54 compares each pixel of the dust detection image acquired in step S23 with a predetermined value (step S30), and dust is applied to a pixel portion having a pixel value equal to or larger than the predetermined value. Assuming that the image 93 exists, the position information is stored (step S31), and the process returns to step S22.

  If the dust detection instruction has not been sent in the determination in step S22, step S22 is branched to step S32, and the through image processing circuit 54 captures the image data acquired by the imaging for the through image. Capture (step S32), an image for displaying a through image (electronic viewfinder display image) is generated (step S33).

  After generating an image for through image display, the through image processing circuit 54 reads the position information of the dust image 93 stored in step S31 (step S34), and displays the through image according to the position information. The dust image 93 is removed by the dust removing circuit 54a (step S35). This can be performed, for example, by an interpolation calculation using pixels around the position of the dust image 93 (for example, the dust image 93 is replaced with an average value of the surrounding pixels).

  After removing the dust image, the live view image processing circuit 54 displays live view images via the liquid crystal monitor drive circuit 65 (step S36). At this time, the image displayed on the liquid crystal monitor 25 is an image from which the dust image has been removed. In step S36, after the through image display is performed, the through image processing circuit 54 determines whether or not an instruction to stop displaying the through image is sent from the sequence controller 51 (step S37), and stops the through image display. If no instruction has been sent, the process returns to step S22 to continue the through image display. On the other hand, if it is determined in step S37 that a stop instruction to display a through image is sent, the through image display is stopped, and the process returns to step S21.

  As described above, according to the first embodiment, even if dust is attached to the focusing screen 32, it is possible to detect the dust with a simple configuration by detecting the position of the image of the dust imaged thereby. The image can be removed. This prevents the photographer from feeling uncomfortable during the live view display.

  In addition, you may make it guide by a voice etc. instead of the message shown in FIG. 5 may be displayed all at once, or the message or the dust confirmation image may be appropriately switched and displayed according to the operation of the photographer. Furthermore, the dust image 93 may be colored when the dust confirmation image is displayed.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. The second embodiment is different from the first embodiment in a method for making a dust image stand out. FIG. 8 is an external rear perspective view of a digital camera having an electronic viewfinder according to the second embodiment of the present invention. The internal configuration of the digital camera 1 is the same as that described in the first embodiment.

  As shown in FIG. 8, in the second embodiment, by attaching a translucent cap (white cap) 16 to the front surface of the photographic lens 11, the contrast of the subject imaged when capturing an image for dust detection is reduced. To do. The operations of the sequence controller 51 and the through image processing circuit 54 are the same as those in the first embodiment, but the message displayed in step S4 in FIG. 4 is, for example, as shown in FIG. By showing the photographer a message 84 as shown in FIG. 9, the photographer can be prompted to attach the white cap 16 to the front surface of the photographing lens 11.

  According to the second embodiment as described above, it is not necessary to turn the camera 1 toward the sky during imaging for dust detection.

  Although the present invention has been described based on the above embodiments, the present invention is not limited to the above-described embodiments, and various modifications and applications are naturally possible within the scope of the gist of the present invention.

  Further, the above-described embodiments include various stages of the invention, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the column of the effect of the invention Can be extracted as an invention.

1 is an external rear perspective view of a digital camera having an electronic viewfinder according to a first embodiment of the present invention. It is a perspective view which shows the structure of the optical system inside the digital camera main body in the 1st Embodiment of this invention. It is a block diagram for demonstrating the electric circuit structure of the camera which has an electronic viewfinder which concerns on the 1st Embodiment of this invention. It is a flowchart shown about the process of the sequence controller at the time of a through image display. It is a figure which shows an example of the message displayed in the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the through image processing circuit at the time of a through image display. FIG. 7A is a diagram showing a dust detection image, and FIG. 7B is a diagram showing a dust confirmation image. It is an external appearance back perspective view of a digital camera which has an electronic view finder concerning a 2nd embodiment of the present invention. It is a figure which shows an example of the message displayed in the 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Digital camera (camera), 10 ... Lens barrel, 11 ... Shooting lens, 12 ... Lens drive circuit, 13 ... Aperture, 14 ... Aperture drive mechanism, 15 ... Lens CPU, 16 ... White cap, 20 ... Camera body, 25 ... Liquid crystal monitor, 29 ... Cleaning button, 31 ... First reflecting mirror, 32 ... Focusing screen, 33 ... Second reflecting mirror, 34 ... Third reflecting mirror, 35 ... Fourth reflecting mirror, 36 ... Eyepiece, 38 ... Photometric device, 39 ... imaging lens, 40 ... through-image imaging device, 42 ... mirror drive mechanism, 43 ... sub-mirror, 44 ... ranging circuit, 45 ... shutter, 46 ... shutter drive mechanism, 47 ... recording imaging device, 48 ... Image sensor drive circuit, 49 ... Image sensor drive circuit, 50 ... Camera control circuit, 51 ... Sequence controller, 52 ... Bus, 53 ... Communication circuit 54 ... Through image processing circuit, 54a ... Dust removal circuit, 55, 58 ... Image sensor interface circuit, 56 ... Input / output circuit, 57 ... Recording image processing circuit, 59 ... SDRAM control circuit, 60 ... SDRAM, 61 ... Compression circuit, 62 ... Recording medium control circuit, 63 ... Recording medium, 64 ... Video signal output circuit, 65 ... Liquid crystal monitor drive circuit, 66 ... FLASHROM control circuit, 67 ... FLASHROM, 68 ... Switch detection circuit, 69 ... Various SW, 70 ... Data Holding circuit, 71... Display data storage circuit

Claims (8)

In a camera having an electronic viewfinder that captures a subject image on a focusing screen and displays imaging data acquired by imaging as an electronic viewfinder display image.
A low-contrast means for forming a low-contrast image on the focusing screen;
A dust detection means for capturing a low-contrast image formed on the focusing screen and detecting the position of the dust attached to the focusing screen from imaging data obtained by imaging;
Dust removing means for removing the dust image from the electronic viewfinder display image according to the detection result of the dust detecting means;
A camera having an electronic viewfinder.   2. The camera having an electronic viewfinder according to claim 1, wherein the low-contrast means forms the low-contrast image on the focusing screen by moving the position of the photographing lens to a specific position. .   The camera having an electronic viewfinder according to claim 2, wherein the specific position is a closest position of the photographing lens.   2. The camera having an electronic viewfinder according to claim 1, wherein the low contrast means includes a translucent member configured to be attachable to the front surface of the photographing lens.   2. The camera having an electronic viewfinder according to claim 1, wherein a guide display for the dust detection operation is further displayed on the electronic viewfinder during operation of the dust detection means.   2. The camera having an electronic viewfinder according to claim 1, wherein the dust detection means detects the dust image after removing image data of a fixed pattern related to the focusing screen from the imaging data.   7. The camera having an electronic viewfinder according to claim 6, wherein the image data of the fixed pattern is imaging data acquired in a state where dust is not attached to the focusing screen.   2. The camera having an electronic viewfinder according to claim 1, wherein the dust removing means removes the dust image using data of pixels around the dust image.

Images