JP2019155931A - Heating control device - Google Patents

Abstract

To reduce the possibility that a heating part consumes electric power uselessly.SOLUTION: A control ECU is applied to a vehicle including a camera sensor which is arranged inside a window part provided on a vehicle and generates an imaged image PI by imaging a landscape outside the window part over the window part. The control ECU acquires edge strength ES of each of a plurality of edge points showing a border line BL of a traffic lane included in the imaged image and a distance L between each of the plurality of edge points and an imaging part. The control ECU calculates an inclination (a) showing an amount of change in the edge strength in each of a plurality of sections where the distance increases by a prescribed constant distance ΔL when it is determined that prescribed conditions to be satisfied in any case when the window part is fogged and when fog is generated outside the vehicle are satisfied. Then, the control ECU causes a heating part to heat the window part when it is determined that fogging conditions to be satisfied when there exists no section becoming equal to or less than a prescribed threshold ath in which the calculated inclination includes a negative value are satisfied.SELECTED DRAWING: Figure 5

Description

  The present invention is applied to a vehicle including an imaging unit that captures an image of a landscape outside the window part from the inside of the window part provided in the vehicle and generates the captured image, and the window part can be heated. The present invention relates to a heating control device that controls a heating unit.

  When the outside air temperature of the vehicle is low, condensation may occur inside the window portion, and the window portion may be fogged. An image captured by the imaging unit with the window portion clouded tends to be “the subject outline is blurred and the entire image is whitish”, and the imaging unit may not be able to capture an accurate landscape outside the window portion. high. Conventionally, as proposed in Patent Document 1, when the outside air temperature becomes equal to or lower than a set temperature, a heating control device (hereinafter referred to as “conventional”) removes fogging of the window by causing the heating unit to heat the window. Also known as “apparatus”).

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

  However, even when the outside air temperature is higher than the set temperature, the window may be clouded depending on the humidity and / or the passenger compartment temperature.

  Therefore, an apparatus that causes the heating unit to heat the window when clouding of the window is detected based on an image captured by the imaging unit can be considered.

  However, even when fog is generated, the imaging unit cannot capture an accurate landscape as in the case where the window is cloudy. An image picked up in a situation where fog is generated has the same characteristics as an image picked up in a situation where the window is cloudy. Therefore, the above-described “apparatus that simply determines whether or not the window portion is cloudy based on the captured image” cannot determine whether fog is generated or the window portion is cloudy. For this reason, the apparatus mentioned above makes a heating part heat a window part, when the window part is not cloudy but fog has generate | occur | produced. However, since the mist is generated outside the vehicle, it is meaningless and wasteful power is consumed even if the heating unit heats the window when the mist is generated.

  The present invention has been made to address the above-described problems. That is, one of the objects of the present invention is to determine whether the window portion is fogged or foggy, and when it is determined that there is a high possibility that the window portion is fogged. An object of the present invention is to provide a heating control device that can reduce the possibility that the heating unit wastes power by causing the heating unit to heat the window.

The heating control device of the present invention (hereinafter also referred to as “the device of the present invention”)
Imaging units (21 and 24) that are arranged inside windows (45 and 45a) provided in the vehicle and that capture the scenery outside the window through the window and generate a captured image (PI). Applied to vehicles having
A heating part (31) disposed inside the window part and capable of heating the window part;
A control unit (10) for heating the window to the heating unit,
The controller is
Obtaining the edge strength of each of a plurality of edge points indicating boundary lines of a lane included in the generated captured image, and the distance between each of the plurality of edge points and the imaging unit,
When it is determined that the predetermined condition regarding the acquired edge strength is satisfied, which is satisfied in both cases where the window portion is cloudy and fog is generated outside the vehicle (step 530). "Yes"),
The acquired edge strength and the slope (a) indicating the amount of change (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), respectively Based on the acquired distance (step 545), it is determined whether or not a cloudy condition that is satisfied when there is no section where the calculated slope is equal to or less than a predetermined threshold having a negative value ( Step 550),
When it is determined that the fogging condition is satisfied (step 550 “Yes”), the heating unit is caused to heat the window (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 reflected light decreases sharply when the distance from the imaging unit increases from a relatively short point. . For this reason, the edge strength of the boundary lines (white line, yellow line, etc.) that divide the lane is also likely to decrease sharply when the distance from the imaging 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 a section between a certain point and a point far from the imaging unit by a predetermined fixed distance from that point is “negative. There is a high possibility that the value will be equal to or lower than a “predetermined threshold value having a value”.
On the other hand, when the window is cloudy, it is highly possible that the entire picked-up image will only stagnate and become white, and a sharp decrease in edge strength will not occur as in the case where fog is generated outside the vehicle.

  The device according to the present invention determines that the predetermined condition regarding the acquired edge strength is satisfied, which is satisfied in any case where the window portion is cloudy or fog is generated outside the vehicle. In this case, a 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 imaging unit increases by a predetermined constant distance is calculated. When the apparatus according to the present invention determines that the cloudy condition that is satisfied when there is no section in which the calculated slope is equal to or less than the predetermined threshold having a negative value, the heating unit heats the window.

  Accordingly, the device of the present invention can accurately determine whether the window is cloudy or fog is generated. Furthermore, when it is determined that there is a high possibility that the window portion is cloudy, the device of the present invention causes the heating portion to heat the window portion, and thus causes the heating portion to heat the window portion when fog is generated. The possibility can be reduced. As a result, the possibility of wasteful power consumption can be reduced.

  In the above description, in order to facilitate understanding of the invention, names and / or symbols used in the embodiment are attached to the configuration of the invention corresponding to the embodiment described later in parentheses. However, each component of the invention is not limited to the embodiment defined by the names and / or symbols.

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 heater mounting position shown in FIG. FIG. 3A is an explanatory diagram of a captured image captured in a situation where the light transmission unit illustrated 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 when normal, the edge strength when the light transmission part is cloudy, and the edge strength and 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.

  A heating control device according to an embodiment of the present invention (hereinafter sometimes referred to as “the present control device”) is applied to a vehicle. As shown in FIG. 1, the control device includes a control ECU 10, a heater (hereinafter sometimes referred to as “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 electrical control unit that includes a microcomputer as a main part. In this specification, the microcomputer includes a CPU, a ROM, a RAM, a nonvolatile memory, an interface (I / F), and the like. The CPU implements various functions by executing instructions (programs, routines) stored in the ROM.

  As shown in FIG. 2, the camera sensor 21 is disposed at the center in the vehicle width direction near the upper edge of the rear surface (that is, the vehicle inner surface) of the vehicle front window 45. More specifically, a light shielding sheet 46 having an overall T-shape is attached to the upper edge portion of the rear surface of the front window 45 and its vicinity. A front extension 46 a extending obliquely downward in the front direction is formed at the center 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. By adhering this adhesive surface to the lower surface of the front extension 46a, the camera sensor 21 is fixed to the lower surface of the front extension 46a.

  A light transmitting hole 46b having a substantially trapezoidal shape is formed in the vicinity of the front end of the front extending portion 46a, and a portion of the front window 45 facing the light transmitting hole 46b is referred to as a light transmitting portion 45a (hereinafter referred to as a “window portion”). In some cases). For this reason, when the camera sensor 21 is fixed to the lower surface of the front extension 46a, the imaging unit 24 included in the camera sensor 21 is positioned at a position facing the light transmission hole 46b.

  For this reason, the imaging unit 24 captures the reflected light reflected backward by a target (for example, another vehicle) located in front of the front window 45 (ie, in front of the vehicle) every time a predetermined time elapses. To obtain a captured image. The reflected light passes through the light transmission part 45 a of the front window 45 and the light transmission hole 46 b of the light shielding sheet 46 and reaches the imaging part 24. Then, the imaging unit 24 transmits the acquired captured image to an image processing device (not shown) provided in the camera sensor 21.

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

  Based on the target information, the control ECU 10 executes “automatic brake control, lane keeping assist control (lane tracing assist control) and adaptive high beam control”, etc., performs automatic driving, and issues an alarm. . 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 partial region of the camera sensor 21. More specifically, the heater 31 is provided in a region located below the light transmission part 45a and facing the entire surface of the light transmission part 45a when the camera sensor 21 is fixed to the front extension part 46a. It is 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 a power source mounted on the vehicle and the heater 31 is energized, 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 transmission part 45a is cloudy, when the light transmission part 45a is heated by the heater 31 and the temperature near the light transmission part 45a becomes equal to or higher than the dew point temperature, the cloudiness disappears. Furthermore, even when ice and / or frost adheres to the light transmission part 45a and the light transmission part 45a is cloudy, the heater 31 heats the light transmission part 45a, thereby increasing the temperature of the light transmission part 45a. Ice and / or frost can be melted.

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

(Overview of operation)
Next, an outline of the operation of the present control device will be described.
This control apparatus 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 extracts the extracted boundary line. A target line OL (see FIG. 3A) to be processed is extracted from BL. Then, the present control device calculates an 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 a predetermined value. It is determined whether or not the threshold intensity ESth is less than or equal to.

  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 transmission part 45a is cloudy or fog is generated outside the vehicle.

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

Here, the cloudy condition will be described.
This control apparatus has a slope a1 indicating a change amount ΔES (see FIG. 4) of the edge strength ES in a unit section having a predetermined distance ΔL (see FIG. 4) in the relationship between the edge strength ES and the distance L. Thru aN (“N” is a natural number equal to or greater than “2”). Since the edge strength ES decreases as the distance L increases, each of the inclinations a1 to aN has a negative value. Then, the present control apparatus determines whether or not the calculated inclinations a1 to aN include “an inclination a that is less than a predetermined threshold ath that is smaller than 0”. When the inclination a does not exist in the inclinations a1 to aN, the present control device determines that the clouding condition is satisfied and determines that the light transmission portion 45a is cloudy. On the other hand, when the inclination a is present in the inclinations a1 to aN, the present 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 under the condition where the light transmission part 45a is cloudy has a high possibility that the entire image is blurred (hazy) to the same extent. On the other hand, as shown in FIG. 3B, the captured image PIf captured in a situation where fog is generated outside the vehicle increases as the distance from the imaging unit 24 increases. In other words, in the captured image PIf, it seems that the fog density increases as the distance from the imaging unit 24 increases.

  The cause of fogging of the light transmission part 45a is dew condensation adhering over the entire inner area of the light transmission part 45a and / or ice adhering over the entire outer area of the light transmission part 45a (including snow and frost). Condensation and / or ice adhering to the light transmission part 45a appear in the captured image PIc captured under such circumstances, and the entire captured image PIc is stagnated to the same extent.

  The intensity LS of reflected light incident on the imaging unit 24 tends to attenuate as the distance L from the reflection point of the reflected light to the imaging unit 24 increases. When the amount of fine particles (such as water droplets) contained in a unit volume in the atmosphere is relatively large, the reflected light intensity LS decreases rapidly from a point where the distance L is relatively short as the distance L increases gradually. The possibility increases. Therefore, the intensity LS of the reflected light when fog is generated outside the vehicle is likely to decrease rapidly from a point where the distance L is relatively short as the distance L gradually increases. Note that the edge intensity ES acquired from the region where the intensity LS of the reflected light LS of the captured image PI is attenuated and weakened (becomes smaller) becomes smaller.

FIG. 4 shows the relationship between the edge intensity ES and the distance L acquired from the same target line OL of the captured images PI captured from the same position under the following conditions (A) to (C) (that is, the target line). The relationship between the intensity of an edge point indicating OL and the distance L to the edge point).
(A) The light transmission part 45a is not cloudy and fog is not generated outside the vehicle (when normal)
(B) The light transmitting portion 45a is cloudy (when cloudy)
(C) The situation where fog is generated outside the vehicle (when fog occurs)

  As shown in FIG. 4, the edge strength ES at (A) normal time and (B) cloudy time gradually decreases as the distance L increases. On the other hand, (C) the edge intensity ES at the time of fog occurrence decreases sharply from a relatively short distance La when the distance L increases. For this reason, when fog has occurred, the average edge strength AvES is less than or equal to the threshold strength ESth, and the edge strength ES is likely to decrease rapidly from a certain point as the distance L increases. Therefore, when fog is generated, there is a high possibility that “the slope a that is less than the threshold value ath smaller than 0” exists in the slopes a1 to aN corresponding to the sections having the constant distance ΔL. In the example shown in FIG. 4, the slope a5 of the edge strength ES when fog occurs is the slope a.

  Further, as shown in FIG. 4, (B) the edge strength ES when cloudy is (A) generally smaller than the edge strength ES when normal. This is due to the stagnation of the captured image PI caused by the condensation and / or ice adhering to the light transmission part 45a. For this reason, when the light transmission part 45a is cloudy, there is a high possibility that the average edge intensity AvES is equal to or less than the threshold intensity ESth, but the inclination a described above exists in the relationship between the edge intensity ES of the target line OL and the distance L. There is a high possibility of not.

  Therefore, the present control device first determines whether or not the average edge strength AvES is equal to or less than the threshold strength ESth. That is, the present control apparatus has a “predetermined condition regarding the edge strength ES” that is established in any case where the window portion, which is the light transmission portion 45a, is cloudy, or when fog is generated outside the vehicle 10. It is determined whether it is established. Then, when the average edge intensity AvES is equal to or less than the threshold intensity ESth, the present control apparatus determines that the cloudy condition is satisfied when the above-described inclination a does not exist in the inclinations a1 to aN calculated from the target line OL. The heater 31 is caused to heat the light transmission part 45a. On the other hand, when the above-described inclination a exists in the inclinations a1 to aN, the present control device determines that fog is generated outside the vehicle, and does not cause the heater 31 to heat the light transmission portion 45a. Thereby, it can be determined more accurately whether the light transmission part 45a is cloudy or fog is generated outside the vehicle. Furthermore, 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 consumes power wastefully can be reduced.

(Specific operation)
The CPU of the control ECU 10 executes the routine shown in the flowchart in 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 transmission part 45a and the state outside the vehicle.

  Therefore, when the predetermined timing comes, the CPU starts processing from step 500 in FIG. 5, executes step 505 and step 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 edge points included in the captured image PI acquired in step 505 using a known method, and detects the boundary line BL based on the extracted edge points. A method of detecting the boundary line BL based on the 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 and yellow.

A method for detecting the boundary line BL will be briefly described. First, the CPU extracts, as an edge point, a point where the brightness value increases or decreases rapidly based on the brightness value of the captured image PI. The point where the luminance value increases rapidly is also referred to as a “rising edge point” for convenience. The point at which the luminance value rapidly decreases is also referred to as a “falling edge point” for convenience. These edge points have an edge strength ES that increases as the amount of change in luminance at that edge point increases. Next, the CPU converts the edge point into a planar view image using a well-known Hough transform. Then, the CPU selects, as candidate lines, rising lines that pass through a plurality of rising edge points and falling lines that pass through a plurality of falling edge points, respectively. Next, the CPU selects a rising line and a falling line satisfying the lateral position restriction and satisfying the angle restriction among the candidate lines, and selects a pair whose distance between the two is within a predetermined distance as “a section defining the boundary line BL”. Select as "Line". Then, the CPU selects an area between the selected pair as the boundary line BL. In the lateral position restriction, the candidate line passes through a predetermined range from the left end of the vehicle to a position separated by a predetermined distance in the left direction, or a predetermined range from the right end of the vehicle to a position separated by a predetermined distance in the right direction. It is a restriction to pass. The angle restriction is a restriction that the size of the angle formed by the extension line in the left-right direction of the front end portion of the vehicle and the candidate line is a predetermined angle or less.
In the example shown in FIGS. 3A and 3B, the CPU extracts 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 example shown in FIGS. 3A and 3B, it is assumed that the boundary line BL2 is closest to the vehicle. For this reason, the CPU extracts the boundary line BL2 as the target line OL in step 515.
Step 520: The CPU acquires an edge strength ES of an edge point 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 that define 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 strengths ES acquired in step 520 by “the total number of edge points included in the target line OL”. To 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 fogging of the light transmission part 45a nor fog outside the vehicle has occurred. In this case, the CPU makes a “No” determination at step 530 to execute step 535 described below, and proceeds to step 595 to end the present routine tentatively.

  Step 535: The CPU stops supplying 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, the possibility that the light transmission part 45a is clouded is very low, and the heater 31 does not need to heat the light transmission part 45a. If power is not supplied to the heater 31 at this time, the CPU executes the process of step 535 to confirm that power is not supplied to the heater 31.

  Thereafter, it is assumed that the average edge intensity AvES is equal to or less than the threshold intensity ESth because the captured image PI is stagnated due to the light transmission portion 45a becoming cloudy and the edge intensity ES of the target line OL is reduced. In this case, when the CPU proceeds to step 530, the CPU makes a “Yes” determination at step 530 to execute step 540 and step 545 described below in this order, and then proceeds to step 550.

  Step 540: The CPU plots each edge point on the target line OL on a graph having “edge strength ES of the edge point” on the vertical axis and “distance L between the edge point and the imaging unit 24” on the horizontal axis. To do. Further, the CPU calculates an approximate line AL indicating 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 equation of a straight line passing through adjacent points, and calculates the approximate line AL by obtaining such a straight line for all the 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 (average values of the slopes) a1 to aN of the approximate lines AL in each section. To do. More specifically, the CPU calculates the change amount ΔES of the edge strength ES of the approximate line AL in each section. The amount of change ΔES is approximated by the approximate line AL when the distance L is a certain distance (L1 + ΔL), and the edge strength ES approximated by the approximate line AL when the distance L is the certain distance L1. When the edge strength ES is the edge strength ES2, it is calculated by the following equation.

ΔES = ES2-ES1

Then, the CPU calculates the gradients a1 to aN by dividing the calculated change amount ΔES of each section by the 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 ath. The threshold value ath is set to a value smaller than “0”, that is, a negative value. In other words, the CPU determines whether or not there is an inclination a in which the magnitude (absolute value) of the inclination is greater than or equal to a positive threshold (= | ath | = −ath) among the inclinations a1 to aN. .

  When the light transmission part 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 becomes longer. There is no inclination a. Accordingly, when the slope a does not exist, it can be determined that the cloudy condition is satisfied, so the CPU determines “No” in step 550, executes step 555 and step 560 described below in this order, and step 595. Proceed to to end the present routine.

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

  When the fog of the light transmission part 45a is removed by the heating of the heater 31, a captured image PI without stagnation can be taken. The average edge intensity AvES of the target line OL of such a captured image PI is larger than the threshold intensity ESth. In this case, the light transmission part 45a is not cloudy and fog is not generated outside the vehicle. Therefore, when the CPU proceeds to step 530, the CPU makes a “No” determination at step 530 to proceed to step 535. In step 535, the CPU stops the supply of power to the heater 31, proceeds to step 595, and once ends this routine. Accordingly, it is possible to accurately detect that the fog is removed from the light transmission part 45a, and when the fog is removed from the light transmission part 45a, the power supply to the heater 31 is stopped, so that the electric power consumed wastefully. Can be reduced.

  On the other hand, when fog occurs outside the vehicle, the intensity LS of reflected light has a certain level of strength up to a point where the distance L is relatively short, but abruptly attenuates when the distance L increases beyond that point. For this reason, the average edge intensity AvES of the target line OL of the captured image PI when fog occurs outside the vehicle is equal to or less than the threshold intensity ESth. In this case, when the CPU proceeds to step 530, the CPU determines “Yes” at step 530 and proceeds to step 550 via steps 540 and 545.

  As described above, when fog is generated outside the vehicle, when the distance L increases from a certain value, the reflected light intensity LS abruptly attenuates, so that the edge intensity ES of the target line OL also decreases abruptly. For this reason, “the slope a that is equal to or less than the threshold value ath” exists in the slopes a1 to aN calculated in step 545. Therefore, the CPU makes a “No” determination at step 550 to execute step 565 and step 570 described below in this order. Thereafter, the CPU proceeds to step 595 to end the present routine tentatively.

Step 565: The CPU stops supplying power to the heater 31. This is because the fog cannot be removed even if power is supplied to the heater 31 when fog is generated outside the vehicle.
Step 570: The CPU displays a fog generation display on the display 32 and outputs a fog generation sound to the speaker 33 in order to notify the driver that fog has occurred outside the vehicle. More specifically, the CPU executes a process of displaying a message “Fog is occurring” and / or a specific warning symbol on the display 32, and outputs a predetermined warning sound from the speaker 33. Execute the process to output. Similarly to the case where the light transmission part 45a is cloudy, when the fog is generated, the driving support control based on the captured image PI is not performed. Know why control is not being implemented.

  As 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 present control device heats the light transmitting portion 45a to the heater 31 when the cloudy condition is satisfied. Let This clouding condition is obtained when there is no slope a that is equal to or less than the “threshold value ath set to a negative predetermined value” in the slopes a1 to aN of the approximate curve AL of the edge intensity ES of the target line OL for each predetermined distance ΔL. To establish.

  When fog is generated outside the vehicle, when the distance L increases from a certain value, there is a high possibility that the edge intensity ES will also rapidly decrease due to the intensity of the reflected light beginning to attenuate rapidly. For this reason, when fog is generated outside the vehicle, there is a high possibility that there is an inclination a that is equal to or less than the threshold value ath among the inclinations a1 to aN. Therefore, when fog is generated outside the vehicle, there is a high possibility that the above-described fogging condition is not satisfied. For this reason, since the possibility that the fogging condition is satisfied is reduced when fog is generated outside the vehicle, the present control device can reduce the possibility of causing the heater 31 to heat the light transmission portion 45a wastefully. . Accordingly, when fog is generated outside the vehicle, the possibility that the heater 31 consumes useless power can be reduced.

<Modification>
In the modification of the embodiment of the present invention, when the average edge intensity AvES of the target line OL is equal to or less than the threshold intensity ESth, the slopes a1 to aN of the approximate lines AL of the edge intensity ES of the target line OL become “threshold value ath or less. Even if the inclination “a” exists, it is determined that the cloudy condition is satisfied when the following stationary object condition is satisfied.

(Stationary object conditions)
“Approximate line of edge strength 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 imaging unit 24 ”. No slope b that is less than or equal to “a predetermined threshold value bth smaller than 0” is present in the slopes b1 to bN.

  The distance L between the “stationary object (for example, a sign or the like) present on the moving direction side of the vehicle” and the imaging unit 24 becomes shorter as time passes while the vehicle moves in the moving direction. This control device detects a stationary object that is identified as the same in the captured image PI that is captured every time a predetermined time has elapsed.

  More specifically, this control device stores in advance the image feature amount of the stationary object to be detected. The present control device divides the captured image PI into “a plurality of regions having a predetermined area” and calculates an image feature amount of each divided region. Then, if the difference between the calculated image feature quantity and the stationary object image feature quantity is equal to or less than a predetermined value, the control device detects the area where the image feature quantity is calculated as the stationary object area. .

  Furthermore, this modification includes a vehicle speed sensor (not shown) that detects the speed (vehicle speed) of the vehicle and a yaw rate sensor (not shown) that detects 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. And after a stationary object is once detected, this modification estimates the estimated position which shows the position after the predetermined time of the detected stationary object passes based on an estimated course. When a region having an image feature amount similar to the image feature amount of the stationary object exists in the vicinity of the position corresponding to the predicted position of the captured image PI after a predetermined elapse, the control device selects the stationary object in the region. It recognizes that it is the same as the stationary object detected last time.

  After detecting a stationary object by the method as described above, the present modification acquires the edge strength ES of the detected stationary object. 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 an approximate line AL ′ of the edge strength ES of the target is calculated. By repeating such processing, it is grasped how the edge strength ES of the target changes corresponding to the distance L.

  In addition, when the camera sensor 21 is a stereo camera, the distance L between the stationary object and the imaging 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 a radar sensor (not shown) included in the present control device and the captured image PI captured by the monocular camera. . A radar sensor is a sensor that detects information related to the position of a target by radiating a wireless medium and receiving the reflected wireless medium.

  When fog is generated outside the vehicle, the edge strength ES of the stationary object is also a certain strength when the distance L to the imaging unit 24 is shorter than a certain distance, but the distance exceeds a certain distance. And suddenly decreases. Therefore, in the present modification, the approximate line AL ′ is divided into a plurality of sections, and the slopes (average values of slopes) b1 to bN of the approximate lines AL ′ in each section are calculated. It is determined whether or not there is a slope “b” that is less than or equal to bth.

  In the case where the inclination b does not exist among the inclinations b1 to bN, the present modified example indicates that even if the inclination a exists in the inclinations a1 to aN of the target line OL, “no fog is generated, It is determined that the cloudy condition has been established. Then, in this modification, when it is determined that the cloudy condition is established, the heater 31 is caused to heat the light transmission portion 45a.

  Since the target line OL is the boundary line BL, the edge strength ES of the target line OL may rapidly decrease as the distance L increases depending on the road surface condition, the boundary line bending method, and the like. In particular, when there is a puddle covering the boundary line BL, there is a high possibility that the edge strength ES of the part will rapidly decrease. Accordingly, it may be determined that the inclination a is present among the inclinations a1 to aN even though the light transmission portion 45a is cloudy and no fog is generated outside the vehicle. However, even in such a case, the inclination b does not exist in the inclinations b1 to bN. Therefore, in this modification, the light transmission portion 45a is cloudy, not fog is generated. Can be determined.

  Note that when a plurality of stationary objects are detected, the present modification performs the above-described processing on each stationary object. As a result, in the present modification, when the inclination b does not exist among the inclinations b1 to bN of the approximate line AL ′ of the edge strength ES of any stationary object, 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 a similar determination can be performed for a moving object such as a preceding vehicle.

  Further, the present modification may include a current position acquisition unit (for example, a GPS sensor) (not shown) that acquires the current position of the vehicle, and a database that stores map information that can specify 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 embodiments, and various modifications of the present invention can be employed.
For example, in step 520, the present control device may acquire the edge strength ES from the edge points of the rising line and the falling line that define the boundary line BL that is the target line OL.
Further, in step 515, the present control apparatus may set all the extracted boundary lines BL 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.

  Furthermore, both the captured image PI captured when the light transmission part 45a is clouded and the captured image PI captured when fog is generated outside the vehicle are highly likely to be white as a whole. For this reason, this control apparatus converts the captured image PI into a gray scale, and calculates an average luminance value, which is an average of pixel values included in the captured image PI after conversion into the gray scale, as whiteness. The higher the average luminance value (that is, the higher the whiteness), the higher the whiteness. And this control apparatus determines with the whole image being white, when whiteness is more than threshold whiteness. Next, the present control device determines whether 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 that is the light transmission part 45a is clouded and the vehicle 10 It is determined whether the “predetermined condition regarding the edge strength ES” that is satisfied in any case where fog is generated is satisfied. And this control apparatus will judge that the light transmission part 45a is cloudy, when predetermined conditions are satisfied and inclination a does not exist in the inclination with respect to the distance L of edge strength ES of the target line OL. Good. Similarly, the present control device determines that fog is generated outside the optical vehicle when the predetermined condition is satisfied and the inclination a exists in the inclination of the target line OL with respect to the distance L of the edge intensity ES. May be.

  Furthermore, instead of step 530, the present control device may determine whether or not the predetermined condition is satisfied only by determining whether or not the whiteness is equal to or greater than a threshold whiteness. In this case, if the whiteness is equal to or greater than the threshold whiteness, the control device determines “Yes” in step 530 and proceeds to the processing from step 540 onward. On the other hand, if the whiteness is less than the threshold whiteness, the control device determines “No” in step 530 and proceeds to the processing of step 535.

  As described above, the processing in step 530 is based on the captured image PI to determine whether a predetermined condition that is satisfied when the light transmission part 45a is cloudy or fog is generated outside the vehicle is satisfied. What is necessary is just the process to determine. In the present embodiment and the modification, as an example of such processing, processing using average edge strength AvES and processing using whiteness are shown.

  Further, the present control device may change the threshold value ath according to the color of the boundary line BL extracted as the target line OL. When fog is generated outside the vehicle, the area where the fog is dark on the captured image PI is white, and the white boundary line BL is the same as the white due to the fog. For this reason, 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, when the white boundary line BL is selected as the target line OL, the present control device sets the “threshold value ath smaller than 0” to a smaller value than when the other color boundary line BL is selected. It may be set.

  Furthermore, the present control device may change the threshold value ath 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 than when 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. For this reason, when the average luminance value of the captured image PI is high, the sharp decrease amount of 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 get smaller. Therefore, this control apparatus may set the threshold value ath when the average luminance value of the captured image PI is high to a value larger than the threshold value ath when the average luminance value of the captured image PI is low.

  Furthermore, the camera sensor 21 may be attached to a window part 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.

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

Claims (1)

Applied to a vehicle having an imaging unit that is disposed inside a window provided in the vehicle and that captures a scenery outside the window through the window and generates a captured image.
A heating part disposed inside the window part and capable of heating the window part;
A controller that causes the heating unit to heat the window,
The controller is
Obtaining the edge strength of each of a plurality of edge points indicating boundary lines of a lane included in the generated captured image, and the distance between each of the plurality of edge points and the imaging unit,
When it is determined that the predetermined condition regarding the acquired edge strength is satisfied, which is satisfied in any case where the window portion is cloudy and when fog is generated outside the vehicle,
A slope indicating a change amount of the acquired edge strength in each of a plurality of sections in which the distance from the imaging unit increases by a predetermined constant distance is calculated based on the acquired edge strength and the acquired distance. Determining whether or not a cloudy condition that is satisfied when there is no section in which the calculated slope is equal to or less than a predetermined threshold having a negative value,
When it is determined that the cloudy condition is satisfied, the heating unit is caused to heat the window portion,
A heating control device configured as described above.

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