JP7006385B2 - Heating control device - Google Patents

Description

The present invention is applied to a vehicle provided with an image pickup unit that captures a landscape outside the window portion from the inside of the window portion provided in the vehicle through the window portion to generate an image, and can heat the window portion. The present invention relates to a heating control device that controls a heating unit.

If the outside air temperature of the vehicle is low, dew condensation may occur inside the window and the window may become cloudy. An image captured by the image pickup unit with the window portion cloudy tends to have "the outline of the subject is blurred and the entire image is whitish", and the image pickup unit may not be able to capture an accurate landscape outside the window portion. high. As conventionally proposed in Patent Document 1, when the outside air temperature becomes equal to or lower than the set temperature, a heating control device for removing fogging of the window portion by heating the window portion by the heating portion (hereinafter, "conventional"). It is also known as a "device").

JP-A-2017-185896 (see paragraphs 0065 and 0066, etc.)

However, even when the outside air temperature is higher than the set temperature, the window portion may become cloudy depending on the humidity and / or the vehicle interior temperature and the like.

Therefore, when the image pickup unit detects cloudiness of the window portion based on the image captured by the image pickup unit, a device for heating the window portion by the heating unit can be considered.

However, even when fog is generated, the image pickup unit cannot capture an accurate landscape as in the case where the window portion is cloudy. The image captured under the condition of fog has the same characteristics as the image captured under the condition that the window portion is cloudy. Therefore, the above-mentioned "device that simply determines whether or not the window portion is cloudy based on the captured image" cannot determine whether the fog is generated or the window portion is cloudy. Therefore, in the above-mentioned device, when the window portion is not cloudy but fog is generated, the heating portion heats the window portion. However, since the fog is generated outside the vehicle, it is meaningless to have the heating unit heat the window portion when the fog is generated, and wasteful electric power is consumed.

The present invention has been made to address the above-mentioned problems. That is, one of the objects of the present invention is when it is determined whether the window portion is cloudy or foggy, and it is determined that there is a high possibility that the window portion is cloudy. It is an object of the present invention to provide a heating control device capable of reducing the possibility that the heating unit wastefully consumes electric power by causing the heating unit to heat the window unit.

The heating control device of the present invention (hereinafter, also referred to as “the device of the present invention”) is
Imaging units (21 and 24) arranged inside the windows (45 and 45a) provided in the vehicle and capturing the landscape outside the window through the window to generate an image (PI). Applies to vehicles with
A heating portion (31) disposed inside the window portion and capable of heating the window portion,
The heating unit is provided with a control unit (10) for heating the window unit.
The control unit
The edge intensities of the plurality of edge points indicating the lane boundaries included in the generated captured image and the distance between each of the plurality of edge points and the image pickup unit are acquired.
When it is determined that the predetermined condition regarding the acquired edge strength is satisfied, which is satisfied in both the case where the window portion is cloudy and the case where fog is generated outside the vehicle (step 530). "Yes"),
The slope (a) indicating the change amount (ΔES) of the acquired edge strength in each of the plurality of sections in which the distance from the imaging unit increases by a predetermined constant distance (ΔL) is the acquired edge strength and the said. It is calculated based on the acquired distance (step 545), and it is determined whether or not the cloudy condition that is satisfied when there is no section in which the calculated slope is equal to or less than a predetermined threshold value having a negative value is satisfied (step 545). Step 550),
When it is determined that the fogging condition is satisfied (step 550 “Yes”), the heating unit heats the window unit (step 555).
It is configured as follows.

When fog is generated outside the vehicle, there are many fine particles (water droplets) present in the atmosphere, so the intensity of the reflected light decreases sharply when the distance from the image pickup unit increases from a relatively short point. .. Therefore, the edge strength of the boundary line (white line, yellow line, etc.) that divides the lane is also likely to decrease sharply when the distance from the image pickup unit increases from a relatively short point. In other words, when fog is generated outside the vehicle, the slope indicating the amount of change in edge strength in the section between a certain point and a point far from the image pickup unit by a predetermined fixed distance from that point is "negative". There is a high possibility that it will be less than or equal to a predetermined threshold having a value.
On the other hand, when the window portion is cloudy, it is highly possible that the entire captured image becomes hazy and white, and the sharp decrease in edge strength as in the case where fog is generated outside the vehicle does not occur.

The apparatus of the present invention determines that the predetermined condition regarding the acquired edge strength, which is satisfied in both the case where the window portion is cloudy and the case where fog is generated outside the vehicle, is satisfied. If so, the slope indicating the amount of change in the edge strength of the boundary line that divides the lane in each of the plurality of sections in which the distance from the image pickup unit increases by a predetermined fixed distance is calculated. Then, the apparatus of the present invention causes the heating unit to heat the window unit when it is determined that the fogging condition that is satisfied when there is no section where the calculated inclination is equal to or less than a predetermined threshold value having a negative value is satisfied.

Thereby, the apparatus of the present invention can accurately determine whether the window portion is cloudy or foggy. Further, in the apparatus of the present invention, when it is determined that the window portion is likely to be cloudy, the heating portion heats the window portion, so that the heating portion heats the window portion when fog is generated. The possibility can be reduced. This can reduce the possibility of wasting power.

In the above description, in order to help the understanding of the invention, the name and / or the reference numeral used in the embodiment are added in parentheses to the structure of the invention corresponding to the embodiment described later. However, each component of the invention is not limited to the embodiment defined by the above name and / or reference numeral.

FIG. 1 is a schematic system configuration diagram of a heating control device (this control device) according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of the mounting position of the heater shown in FIG. FIG. 3A is an explanatory diagram of a captured image captured in a situation where the light transmitting portion shown in FIG. 2 is cloudy. FIG. 3B is an explanatory diagram of a captured image captured in a situation where fog is generated outside the vehicle. FIG. 4 is a graph showing the relationship between the edge strength in the normal state, the edge strength when the light transmitting portion is cloudy, and the edge strength and the distance when fog is generated outside the vehicle. FIG. 5 is a flowchart showing a routine executed by the CPU of the control ECU shown in FIG.

The heating control device according to the embodiment of the present invention (hereinafter, may be referred to as "the control device") is applied to a vehicle. As shown in FIG. 1, the control device includes a control ECU 10, a heater (hereinafter, may be referred to as a “heating unit”) 31, a display 32, and a speaker 33. The vehicle includes a camera sensor 21 connected to the control ECU 10.

The control ECU 10 is an electric control unit (Electronic Control Unit) including a microcomputer as a main part. As used herein, a microcomputer includes a CPU, ROM, RAM, non-volatile memory, an interface (I / F), and the like. The CPU realizes various functions by executing instructions (programs, routines) stored in ROM.

As shown in FIG. 2, the camera sensor 21 is arranged at the center portion in the vehicle width direction near the upper edge portion of the rear surface (that is, the inner surface of the vehicle) of the front window 45 of the vehicle. More specifically, a light-shielding sheet 46 having a substantially T-shape as a whole is attached to the upper edge portion of the rear surface of the front window 45 and the vicinity thereof. A front extending portion 46a extending diagonally forward and downward is formed in the central portion of the light-shielding sheet 46. An adhesive surface (not shown) is provided on the upper surface of the cover 23 that houses the camera sensor 21. The camera sensor 21 is fixed to the lower surface of the front extension portion 46a by adhering the adhesive surface to the lower surface of the front extension portion 46a.

A light transmission hole 46b having a substantially trapezoidal shape is formed in the vicinity of the front end of the front extending portion 46a, and the portion of the front window 45 facing the light transmission hole 46b is referred to as a light transmission portion 45a (hereinafter referred to as a “window portion”). It may be done.). Therefore, when the camera sensor 21 is fixed to the lower surface of the forward extending portion 46a, the image pickup unit 24 provided in the camera sensor 21 is located at a position facing the light transmission hole 46b.

Therefore, the image pickup unit 24 takes an image of the reflected light reflected rearward by a target (for example, another vehicle) located in front of the front window 45 (that is, in front of the vehicle) every time a predetermined time elapses. And acquire the captured image. This reflected light passes through the light transmitting portion 45a of the front window 45 and the light transmitting hole 46b of the light-shielding sheet 46 and reaches the imaging unit 24. Then, the image pickup unit 24 transmits the acquired captured image to an image processing device (not shown) provided in the camera sensor 21.

When the image processing device detects a target existing in front of the vehicle based on the captured image transmitted by the image pickup unit 24, the image processing device acquires the position of the target with respect to the vehicle based on the captured image. Then, the image processing apparatus transmits the acquired position information indicating the position of the target and the target information including the captured image to the control ECU 10 every time a predetermined time elapses.

The control ECU 10 executes "automatic brake control, lane keeping assist control (lane tracing assist control), adaptive high beam control", etc., performs automatic operation, and issues an alarm based on the target information. .. Hereinafter, such control based on the target detected based on the captured image is referred to as driving support control.

As shown in FIG. 2, the heater 31 is provided in a part of the area of the camera sensor 21. More specifically, the heater 31 is provided in a region that is located below the light transmitting portion 45a and faces the entire surface of the light transmitting portion 45a when the camera sensor 21 is fixed to the forward extending portion 46a. Be done. The heater 31 is a heating wire made of a metal (for example, brass) that generates heat when energized. When electric power is supplied to the heater 31 from the power source mounted on the vehicle and the heater 31 is in the energized state, the heater 31 generates heat. Since the heat generated by the heater 31 is transmitted upward, the light transmitting portion 45a is heated. When the light transmitting portion 45a is cloudy, the cloudiness disappears when the light transmitting portion 45a is heated by the heater 31 and the temperature in the vicinity of the light transmitting portion 45a becomes equal to or higher than the dew point temperature. Further, even when ice and / frost adhere to the light transmitting portion 45a and the light transmitting portion 45a is cloudy, the heater 31 heats the light transmitting portion 45a, so that the temperature of the light transmitting portion 45a rises. Can melt ice and / frost.

The display 32 shown in FIG. 1 is a liquid crystal display that receives a display signal from the control ECU 10 and displays the information indicated by the display signal to the driver. Therefore, the display 32 can perform the cloudiness generation display and the fog generation display described later in response to the signal from the control ECU 10. The display 32 may be a head-up display.
The speaker 33 receives a sounding signal from the control ECU 10 and generates a sound corresponding to the sounding signal. Therefore, the speaker 33 can generate the cloudiness generation sound and the fog generation sound, which will be described later, in response to the signal from the control ECU 10.

(Outline of operation)
Next, the outline of the operation of this control device will be described.
This control device extracts "boundary line BL of the lane in which the vehicle travels" (see BL1 and BL2 shown in FIGS. 3A and 3B) from the captured image PI captured this time by a method described later, and the extracted boundary line. The target line OL (see FIG. 3A) to be processed is extracted from the BL. Then, this control device calculates the average value of the edge strength ES of the edge points representing the extracted target line OL (hereinafter, referred to as "average edge strength AvES"), and the calculated average edge strength AvES is predetermined. It is determined whether or not the threshold intensity is ESth or less.

When the captured image PI is blurred (hazy), the average edge intensity AvES is equal to or less than the threshold intensity ESth. In this case, it is considered that the light transmitting portion 45a is cloudy or fog is generated outside the vehicle.

Therefore, in this control device, the edge strength ES of the edge point representing the target line OL in the captured image PI and "between the actual position of the edge point on the target line OL from which the edge strength ES is acquired and the image pickup unit 24". Based on the relationship with "distance L" (see FIG. 4), it is determined whether or not the clouding condition described later is satisfied. When the fogging condition is satisfied, the control device determines that the light transmitting portion 45a is cloudy and causes the heater 31 to heat the light transmitting portion 45a. On the other hand, when the fogging condition is not satisfied, the control device determines that fog is generated outside the vehicle, and does not cause the heater 31 to heat the light transmitting portion 45a.

Here, the cloudy condition will be described.
In the relationship between the edge strength ES and the distance L, the control device has an inclination a1 indicating a change amount ΔES (see FIG. 4) of the edge strength ES in a unit interval having a predetermined distance ΔL (see FIG. 4). To aN (“N” is a natural number of “2” or more) is calculated. Since the edge strength ES becomes smaller as the distance L becomes larger, each of the slopes a1 to aN becomes a negative value. Then, the control device determines whether or not the calculated slopes a1 to aN have a "slope a that is smaller than 0 and is equal to or less than a predetermined threshold value at". When the inclination a does not exist in the inclinations a1 to aN, the control device determines that the fogging condition is satisfied and determines that the light transmitting portion 45a is fogging. On the other hand, when the inclination a exists in the inclinations a1 to aN, the control device determines that the fogging condition is not satisfied and determines that fog is generated outside the vehicle.

As shown in FIG. 3A, the captured image PIc captured in a situation where the light transmitting portion 45a is cloudy is likely to have the same degree of blurring (haze) as the entire image. On the other hand, as shown in FIG. 3B, the captured image PIf captured in a situation where fog is generated outside the vehicle becomes more hazy as the distance from the imaging unit 24 increases. In other words, in the captured image PIf, the fog density seems to increase as the distance from the imaging unit 24 increases.

The cause of fogging of the light transmitting portion 45a is dew condensation adhering to the entire inside of the light transmitting portion 45a and ice adhering to the entire outside of the light transmitting portion 45a (including snow and frost). Condensation and / or ice adhering to the light transmitting portion 45a is reflected on the captured image PIc captured under such a situation, and the entire captured image PIc is blurred to the same extent.

The intensity LS of the reflected light incident on the image pickup unit 24 tends to be attenuated as the distance L from the reflection point of the reflected light to the image pickup unit 24 becomes longer. When the amount of fine particles (for example, water droplets) contained in a unit volume in the atmosphere is relatively large, the intensity LS of the reflected light decreases sharply from a certain point where the distance L is relatively short when the distance L gradually increases. The possibility is high. Therefore, when the distance L gradually increases, the intensity LS of the reflected light when fog is generated outside the vehicle is likely to decrease sharply from a certain point where the distance L is relatively short. The edge intensity ES acquired from the region where the intensity LS of the reflected light of the captured image PI is attenuated and weakened (reduced) becomes small.

FIG. 4 shows the relationship between the edge intensity ES and the distance L (that is, the target line) acquired from the same target line OL of the captured image PI captured from the same position under the situations (A) to (C) shown below. The relationship between the strength of a certain edge point indicating OL and the distance L to the edge point) is shown.
(A) A situation in which the light transmitting portion 45a is not cloudy and no fog is generated outside the vehicle (normal time).
(B) Situation where the light transmitting portion 45a is cloudy (when cloudy)
(C) Situation where fog is generated outside the vehicle (when fog is generated)

As shown in FIG. 4, the edge strength ES at the time of (A) normal and (B) cloudy gradually decreases as the distance L becomes longer. On the other hand, (C) the edge strength ES at the time of fog generation sharply decreases from a relatively short distance La when the distance L becomes long. Therefore, when fog is generated, the average edge strength AvES is less than or equal to the threshold strength ESth, and the edge strength ES is likely to decrease sharply from a certain point as the distance L increases. Therefore, when fog is generated, there is a high possibility that the slopes a1 to aN corresponding to each section having a certain distance ΔL have a “slope a that is smaller than 0 and is equal to or less than the threshold value a”. In the example shown in FIG. 4, the slope a5 of the edge strength ES at the time of fog generation is the slope a.

Further, as shown in FIG. 4, (B) the edge strength ES at the time of cloudiness is a smaller value as a whole than (A) the edge strength ES at the time of normal. This is due to the haze of the captured image PI caused by the reflection of dew condensation and / or ice adhering to the light transmitting portion 45a. Therefore, when the light transmitting portion 45a is cloudy, the average edge strength AvES is likely to be equal to or less than the threshold strength ESth, but the above-mentioned slope a exists in the relationship between the edge strength ES of the target line OL and the distance L. There is a high possibility that it will not be done.

Therefore, the control device first determines whether or not the average edge strength AvES is equal to or less than the threshold strength ESth. That is, in this control device, the "predetermined condition regarding the edge strength ES" that is satisfied in both the case where the window portion of the light transmitting portion 45a is cloudy and the case where fog is generated outside the vehicle 10 is satisfied. Determine if it holds. Then, the control device determines that the cloudiness condition is satisfied when the above-mentioned inclination a does not exist in the inclinations a1 to aN calculated from the target line OL when the average edge intensity AvES is equal to or less than the threshold intensity ESth. The heater 31 heats the light transmitting portion 45a. On the other hand, when the above-mentioned inclination a exists in the inclinations a1 to aN, the control device determines that fog is generated outside the vehicle and does not cause the heater 31 to heat the light transmitting portion 45a. This makes it possible to more accurately determine whether the light transmitting portion 45a is cloudy or fog is generated outside the vehicle. Further, when there is a high possibility that fog is generated outside the vehicle, the heater 31 does not heat the light transmitting portion 45a, so that the possibility that the heater 31 wastefully consumes electric power can be reduced.

(Concrete operation)
The CPU of the control ECU 10 executes the routine shown in the flowchart of FIG. 5 every time a predetermined time elapses. The routine shown in FIG. 5 is a routine for controlling the heater 31 according to the state of the light transmitting portion 45a and the state outside the vehicle.

Therefore, at a predetermined timing, the CPU starts the process from step 500 in FIG. 5, executes steps 505 and 525 described below in this order, and proceeds to step 530.

Step 505: The CPU acquires the captured image PI from the camera sensor 21.
Step 510: The CPU extracts the edge points included in the captured image PI acquired in step 505 and detects the boundary line BL based on the extracted edge points by using a well-known method. A method for detecting a boundary line BL based on an edge point is well known and is described in, for example, Japanese Patent Application Laid-Open No. 2013-105179. The color of the boundary line BL includes white, orange, yellow, and the like.

The method of detecting the boundary line BL will be briefly described. First, the CPU extracts a point at which the luminance value rapidly increases or decreases based on the luminance value of the captured image PI as an edge point. The point at which the luminance value increases sharply is also referred to as a "rising edge point" for convenience. The point at which the luminance value decreases sharply is also referred to as a "falling edge point" for convenience. These edge points have a larger edge strength ES as the amount of change in luminance at the edge points increases. The CPU then transforms the edge points into a planar image using a well-known Hough transform. Then, the CPU selects a rising line passing through the plurality of rising edge points and a falling line passing through the plurality of falling edge points as candidate lines. Next, the CPU selects a rising line and a falling line that satisfy the horizontal position limit and the angle limit from the candidate lines, and sets the pair in which the distance between the two is within a predetermined distance as "a section for partitioning the boundary line BL". Select as "Line". Then, the CPU selects the area between the selected pairs as the boundary line BL. The lateral position restriction is that the candidate line passes through a predetermined range from the left end of the vehicle to a position a predetermined distance to the left, or a predetermined range from the right end of the vehicle to a position a predetermined distance to the right. It is a restriction to pass. The angle limit is a limit that the size of the angle formed by the extension line in the left-right direction of the front end of the vehicle and the candidate line is not more than a predetermined angle.
In the example shown in FIGS. 3A and 3B, the CPU extracts the boundary lines BL1 and BL2 in step 510.

Step 515: The CPU extracts the boundary line BL closest to the vehicle as the target line OL. In the examples shown in FIGS. 3A and 3B, it is assumed that the boundary line BL2 is closest to the vehicle. Therefore, the CPU extracts the boundary line BL2 as the target line OL in step 515.
Step 520: The CPU acquires the edge strength ES of the edge points included in the target line OL. More specifically, the CPU acquires the edge strength ES of the edge point of the line closest to the vehicle among the rising line and the falling line defining the target line OL.
Step 525: The CPU calculates the average edge strength AvES of the target line OL based on the edge strength ES acquired in step 520. More specifically, the CPU calculates the average edge strength AvES by dividing the total value of all the edge strength ESs acquired in step 520 by the "total number of edge points included in the target line OL". do.
Step 530: The CPU determines whether or not the average edge strength AvES calculated in step 525 is equal to or less than the threshold strength ESth.

When the average edge intensity AvES is larger than the threshold intensity ESth, it is considered that neither cloudiness of the light transmitting portion 45a nor fog outside the vehicle is generated. In this case, the CPU determines "No" in step 530, executes step 535 described below, proceeds to step 595, and temporarily ends this routine.

Step 535: The CPU stops the supply of electric power from the power source to the heater 31. This is because when the average edge intensity AvES is larger than the threshold intensity ESth, it is extremely unlikely that the light transmitting portion 45a is cloudy, so that the heater 31 does not need to heat the light transmitting portion 45a. If the electric power is not supplied to the heater 31 at this time, the CPU executes the process of step 535 to confirm that the electric power is not supplied to the heater 31.

After that, it is assumed that the captured image PI becomes hazy due to the light transmission portion 45a starting to become cloudy, and the edge intensity ES of the target line OL becomes smaller, so that the average edge intensity AvES becomes equal to or less than the threshold intensity ESth. In this case, when the CPU proceeds to step 530, the CPU determines "Yes" in the step 530, executes steps 540 and 545 described below in this order, and proceeds to step 550.

Step 540: The CPU plots each edge point on the target line OL on a graph with the "edge strength ES of the edge point" as the vertical axis and the "distance L between the edge point and the image pickup unit 24" as the horizontal axis. do. Further, the CPU calculates an approximate line AL showing the relationship between the edge strength ES of the target line OL and the distance L based on the plotted points. For example, the CPU calculates an approximate line AL by calculating an equation of a straight line passing through adjacent points and obtaining such a straight line for all points of the edge strength ES of the target line OL.

Step 545: The CPU divides the approximate line AL calculated in step 540 "in units of a plurality of sections having a predetermined distance ΔL" and calculates the slopes (mean values of slopes) a1 to aN of the approximate lines AL in each section. do. More specifically, the CPU calculates the amount of change ΔES of the edge strength ES of the approximate line AL in each section. The amount of change ΔES is the edge strength ES approximated by the approximation line AL when the distance L is a certain distance L1, and is approximated by the approximation line AL when the distance L is a certain distance (L1 + ΔL). When the edge strength ES is set to the edge strength ES2, it is calculated by the following formula.

ΔES = ES2-ES1

Then, the CPU calculates the slopes a1 to aN by dividing the calculated change amount ΔES in each section by a predetermined distance ΔL.

Step 550: The CPU determines whether or not the slope a1 to aN calculated in step 545 has a slope a that is equal to or less than a predetermined threshold value. The threshold value at is set to a value smaller than "0", that is, a negative value. In other words, the CPU determines whether or not there is a slope a in the slopes a1 to aN whose slope magnitude (absolute value) is equal to or greater than a positive threshold value (= | as | =-ath). ..

When the light transmitting portion 45a is cloudy, as shown in FIG. 4 ((B) of FIG. 4), the edge intensity ES of the target line OL gradually decreases as the distance L increases, so that the slopes a1 to aN The above inclination a does not exist in. Therefore, if it can be determined that the cloudiness condition is satisfied when the inclination a does not exist, the CPU determines "No" in step 550, executes steps 555 and 560 described below in this order, and steps 595. Proceed to and terminate this routine once.

Step 555: The CPU starts supplying electric power to the heater 31. That is, since the CPU determines that the light transmitting portion 45a is cloudy, the CPU supplies the electric power to the heater 31 to cause the heater 31 to heat the light transmitting portion 45a.
Step 560: In order to notify the driver that the light transmitting portion 45a is cloudy, the CPU displays the cloudiness occurrence display on the display 32 and outputs the cloudiness generation sound to the speaker 33. More specifically, the CPU executes a process of displaying a message "The front window is cloudy" and / or a specific warning mark on the display 32, and emits a predetermined warning sound from the speaker 33. Execute the process to output. When the light transmitting portion 45a is cloudy, the driving support control based on the captured image PI is not executed. The driver can know the reason why the driving support control is not performed by the cloudiness occurrence display and the cloudiness generation sound.

When the fogging of the light transmitting portion 45a is removed by heating the heater 31, it is possible to take an image PI without haze. The average edge intensity AvES of the target line OL of such a captured image PI becomes larger than the threshold intensity ESth. In this case, the light transmitting portion 45a is not cloudy and no fog is generated outside the vehicle. Therefore, when the CPU advances to step 530, the CPU determines "No" in the step 530 and proceeds to step 535. At step 535, the CPU stops supplying electric power to the heater 31, proceeds to step 595, and temporarily ends this routine. As a result, it is possible to accurately detect that the fogging has been removed from the light transmitting portion 45a, and when the fogging is removed from the light transmitting portion 45a, the power supply to the heater 31 is stopped, so that the power is wasted. The amount of light can be reduced.

On the other hand, when fog is generated outside the vehicle, the intensity LS of the reflected light has a certain intensity up to a point where the distance L is relatively short, but is rapidly attenuated when the distance L becomes large after that point. Therefore, the average edge strength AvES of the target line OL of the captured image PI when fog is generated outside the vehicle is equal to or less than the threshold strength ESth. In this case, when the CPU advances to step 530, the CPU determines "Yes" in the step 530 and proceeds to step 550 via steps 540 and 545.

As described above, when fog is generated outside the vehicle, the intensity LS of the reflected light is abruptly attenuated when the distance L increases from a certain value, so that the edge intensity ES of the target line OL is also abruptly decreased. Therefore, there is a "slope a that is equal to or less than the threshold value a" in the slopes a1 to aN calculated in step 545. Therefore, the CPU determines "No" in step 550, and executes steps 565 and 570 described below in this order. After that, the CPU proceeds to step 595 and temporarily ends this routine.

Step 565: The CPU stops the supply of electric power to the heater 31. This is because when fog is generated outside the vehicle, the fog cannot be removed even if electric power is supplied to the heater 31.
Step 570: The CPU displays the fog generation display on the display 32 and outputs the fog generation sound to the speaker 33 in order to notify the driver that fog is generated outside the vehicle. More specifically, the CPU executes a process of displaying a message "fog is occurring" and / or a specific warning mark on the display 32, and emits a predetermined warning sound from the speaker 33. Execute the process to output. Even when fog is generated, the driver supports the driving by the fog generation display and the fog generation sound because the driving support control based on the captured image PI is not performed as in the case where the light transmitting portion 45a is cloudy. You can see why the control is not enforced.

As can be understood from the above, when the average edge intensity AvES of the target line OL of the captured image PI is equal to or less than the threshold intensity ESth, the control device heats the light transmitting portion 45a to the heater 31 when the fogging condition is satisfied. Let me. This cloudiness condition is satisfied when there is no slope a that is equal to or less than the “threshold value at set to a negative predetermined value” in the slopes a1 to aN for each predetermined distance ΔL of the approximate curve AL of the edge strength ES of the target line OL. To establish.

When fog is generated outside the vehicle, it is highly possible that the edge intensity ES also decreases sharply due to the fact that the intensity of the reflected light begins to decrease sharply when the distance L increases from a certain value. Therefore, when fog is generated outside the vehicle, there is a high possibility that the inclination a that is equal to or less than the threshold value exists in the inclinations a1 to aN. Therefore, when fog is generated outside the vehicle, it is highly possible that the above-mentioned cloudy condition is not satisfied. Therefore, when fog is generated outside the vehicle, the possibility that the cloudy condition is satisfied is low, and the present control device can reduce the possibility that the heater 31 unnecessarily heats the light transmitting portion 45a. .. As a result, when fog is generated outside the vehicle, the possibility that the heater 31 consumes unnecessary electric power can be reduced.

<Modification example>
In the modification of the embodiment of the present invention, when the average edge strength AvES of the target line OL is equal to or less than the threshold strength ES, the slope a1 to aN of the approximate line AL of the edge strength ES of the target line OL becomes “threshold value at or less”. Even if the inclination a ”exists, it is determined that the cloudiness condition is satisfied when the following stationary object condition is satisfied.

(Still object condition)
An approximate line of "edge intensity ES" representing the relationship between the edge intensity ES of a stationary target (hereinafter referred to as "stationary object") and "the distance L between the stationary object and the image pickup unit 24". There is no slope b that is equal to or less than the "predetermined threshold value bth smaller than 0" in the slopes b1 to bN of "".

The distance L between the "stationary object (for example, a sign or the like) existing on the moving direction side of the vehicle" and the image pickup unit 24 becomes shorter as time elapses while the vehicle is moving in the moving direction. This control device detects a stationary object identified as the same in the captured image PI captured every time a predetermined time elapses.

More specifically, the control device stores in advance the amount of image features of the stationary object to be detected. This control device divides the captured image PI into "a plurality of regions having a predetermined area" and calculates the image feature amount of each divided region. Then, if the magnitude of the difference between the calculated image feature amount and the image feature amount of the stationary object is equal to or less than a predetermined value, the control device detects the area in which the image feature amount is calculated as the stationary object area. ..

Further, this modification includes a vehicle speed sensor (not shown) for detecting the speed (vehicle speed) of the vehicle and a yaw rate sensor (not shown) for detecting the yaw rate acting on the vehicle. In this modification, the predicted course of the vehicle is estimated every time a predetermined time elapses based on the vehicle speed detected by the vehicle speed sensor and the yaw rate detected by the yaw rate sensor. Then, after the stationary object is once detected, this modification estimates the predicted position indicating the position after the detected stationary object has elapsed for a predetermined time, based on the predicted course. Then, when the present control device has a region having an image feature amount similar to that of the image feature amount of the stationary object in the vicinity of the position corresponding to the predicted position of the captured image PI after a predetermined lapse, the present control device selects the stationary object in the region. Recognize that it is the same as the stationary object detected last time.

After detecting the stationary object by the method as described above, in this modification, the edge strength ES of the detected stationary object is acquired. Then, in this modification, the relationship between the acquired edge strength ES and the "distance L between the stationary object and the imaging unit 24" is plotted, and the approximate line AL'of the edge strength ES of the target is calculated. By repeating such processing, it is possible to grasp how the edge strength ES of the target changes according to the distance L.

When the camera sensor 21 is a stereo camera, the distance L between the stationary object and the image pickup unit 24 is acquired based on the binocular parallax of the stereo camera. When the camera sensor 21 is a monocular camera, the distance L may be acquired based on the position of the target acquired by the radar sensor (not shown) provided in the control device and the captured image PI captured by the monocular camera. .. A radar sensor is a sensor that detects information about the position of a target by radiating a radio medium and receiving the reflected radio medium.

When fog is generated outside the vehicle, the edge strength ES of the stationary object also becomes a certain strength when the distance L to the image pickup unit 24 is shorter than a certain distance, but the distance exceeds a certain distance. And suddenly become smaller. Therefore, in this modification, the approximate line AL'is divided into a plurality of sections, the slopes (mean values of slopes) b1 to bN of the approximate lines AL'in each section are calculated, and the "threshold" is set in the slopes b1 to bN. It is determined whether or not there is a slope b "that is less than or equal to bth.

When the slope b does not exist in the slopes b1 to bN, in this modification, even if the slope a exists in the slopes a1 to aN of the target line OL, "no fog is generated. The cloudy condition is satisfied. " Then, in this modification, when it is determined that the fogging condition is satisfied, the heater 31 heats the light transmitting portion 45a.

Since the target line OL is the boundary line BL, the edge strength ES of the target line OL may decrease sharply as the distance L increases depending on the road surface condition and the way the boundary line is blurred. In particular, when there is a puddle covering the boundary line BL, there is a high possibility that the edge strength ES of the portion concerned will decrease sharply. As a result, it may be determined that the inclination a exists in the inclinations a1 to aN even though the light transmitting portion 45a is cloudy and no fog is generated outside the vehicle. However, even in such a case, since the inclination b does not exist in the inclinations b1 to bN, in this modification, the light transmitting portion 45a is cloudy instead of fog. It can be determined.

When a plurality of stationary objects are detected, this modification performs the above-mentioned processing for each stationary object. As a result, in this modification, if the slope b does not exist in the slopes b1 to bN of the approximate line AL'of the edge strength ES of any of the stationary objects, it is determined that the stationary object condition is satisfied. In this modification, it is determined whether or not the stationary object condition is satisfied for a stationary object, but the same determination can be made for a moving object such as a preceding vehicle.

Further, this modification may include a current position acquisition unit (for example, a GPS sensor) (not shown) for acquiring the current position of the vehicle, and a database storing map information capable of specifying the position of a stationary object. good. In this case, in this modification, the distance L may be acquired based on the current position of the vehicle and the map information.

The present invention is not limited to the above-described embodiment, and various modifications of the present invention can be adopted.
For example, in step 520, the control device may acquire the edge strength ES from the respective edge points of the rising line and the falling line that partition the boundary line BL which is the target line OL.
Further, in this control device, all the boundary lines BL extracted in step 515 may be used as the target line OL. In this case, the CPU acquires the edge strength ES from the edge points at the same distance L, and uses the average value as the edge strength ES in the subsequent processing.

Further, it is highly possible that the entire image of both the captured image PI captured when the light transmitting portion 45a is cloudy and the captured image PI captured when fog is generated outside the vehicle is white. Therefore, this control device converts the captured image PI into gray scale, and calculates the average luminance value, which is the average of the pixel values included in the captured image PI after conversion to gray scale, as the whiteness. The larger the average luminance value (that is, the larger the whiteness), the higher the whiteness. Then, when the whiteness is equal to or higher than the threshold whiteness, the control device determines that the entire image is white. Next, the control device determines whether or not the entire image is white and the average edge intensity AvES is equal to or less than the threshold intensity ESth, so that the window portion of the light transmitting portion 45a is cloudy and the vehicle 10 It is determined whether or not the "predetermined condition regarding the edge strength ES" that is satisfied in any case where fog is generated outside the above is satisfied. Then, even if the present control device determines that the light transmitting portion 45a is cloudy when the predetermined condition is satisfied and the inclination a does not exist in the inclination of the edge strength ES of the target line OL with respect to the distance L. good. Similarly, the control device determines that fog is generated outside the light vehicle when a predetermined condition is satisfied and a slope a exists in the slope of the edge strength ES of the target line OL with respect to the distance L. You may.

Further, instead of step 530, the control device may determine whether or not the predetermined condition is satisfied by determining only whether or not the whiteness is equal to or higher than the threshold whiteness. In this case, if the whiteness is equal to or higher than the threshold whiteness, the control device determines "Yes" in step 530 and proceeds to the process of step 540 and subsequent steps. On the other hand, when the whiteness is less than the threshold whiteness, the control device determines "No" in step 530 and proceeds to the process of step 535.

As described above, in the process of step 530, it is determined based on the captured image PI whether or not the predetermined condition that is satisfied when the light transmitting portion 45a is cloudy or there is a possibility that fog is generated outside the vehicle is satisfied. Any process may be used for determination. In the present embodiment and the modified example, as an example of such a process, a process using the average edge strength AvES and a process using the whiteness are shown.

Further, the control device may change the threshold value at according to the color of the boundary line BL extracted as the target line OL. When fog is generated outside the vehicle, the region where the fog is thick on the captured image PI becomes dark white, and the white boundary line BL is the same as the white caused by the fog. Therefore, the edge intensity ES of the white boundary line BL tends to decrease more rapidly than the edge intensity ES of the boundary line BL of other colors (for example, orange and yellow). Therefore, this control device sets "threshold value less than 0" to a smaller value when the white boundary line BL is selected as the target line OL than when the boundary line BL of another color is selected. It may be set.

Further, the control device may change the threshold value at depending on whether the average luminance value of the captured image PI is low or high. More specifically, when the average luminance value of the captured image PI is high, it is more likely that the entire captured image PI is white as compared with the case where the average luminance value of the captured image PI is low. In this case, the boundary line BL is often white, the amount of change from the luminance value of the adjacent pixel is small, and the edge strength ES of the boundary line BL is likely to be low. Therefore, when the average luminance value of the captured image PI is high, the amount of sharp decrease in the edge intensity ES of the boundary line BL when fog is generated outside the vehicle is larger than that when the average luminance value of the captured image PI is low. And become smaller. Therefore, the control device may set the threshold value at when the average luminance value of the captured image PI is high to a value larger than the threshold value when the average luminance value of the captured image PI is low.

Further, the camera sensor 21 may be mounted on a window portion different from the front window 45. For example, it may be mounted on a back window (not shown) of the vehicle so that a target located behind the vehicle can be detected.

10 ... Control ECU, 21 ... Camera sensor, 23 ... Cover, 24 ... Imaging unit, 31 ... Heater, 32 ... Display, 33 ... Speaker, BL ... Boundary line, OL ... Target line, ES ... Edge strength.

Claims (2)

It is applied to a vehicle having an image pickup unit, which is arranged inside a window portion provided in the vehicle and has an image pickup unit that captures an image of a landscape outside the window portion through the window portion to generate an image.
A heating unit arranged inside the window portion and capable of heating the window portion,
The heating unit is provided with a control unit for heating the window unit.
The control unit
The edge intensities of the plurality of edge points indicating the lane boundaries included in the generated captured image and the distance between each of the plurality of edge points and the image pickup unit are acquired.
When it is determined that the predetermined condition regarding the acquired edge strength is satisfied, which is satisfied in both the case where the window portion is cloudy and the case where fog is generated outside the vehicle.
A slope indicating the amount of change in the acquired edge strength in each of a plurality of sections in which the distance from the imaging unit increases by a predetermined fixed distance is calculated based on the acquired edge strength and the acquired distance. , It is determined whether or not the cloudy condition that is satisfied when there is no section where the calculated slope is equal to or less than a predetermined threshold value having a negative value is satisfied.
When it is determined that the fogging condition is satisfied, the heating unit heats the window unit.
A heating control device configured to. In the heating control device according to claim 1,
The control unit
If it is determined that the fogging condition is not satisfied, the heating portion does not heat the window portion.
A heating control device configured to.

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