JP7208488B2 - Reflected light detection device, reflected light detection method and program - Google Patents

Description

The present invention relates to a reflected light detection device, a reflected light detection method, and a program.

A technology is known that detects an oncoming vehicle positioned in front of the own vehicle and automatically controls the light distribution of the headlights of the vehicle so that the high beam is not illuminated toward the oncoming vehicle. In addition, a technology has been proposed in which a heat source such as a person or animal is detected by an infrared camera and the light distribution of a headlight is controlled so that the high beam is not illuminated by the person or animal (see, for example, Patent Document 1). .

JP 2013-86739 A

The present inventor paid attention to the glare felt by the driver of the vehicle due to the reflected light of the lighting of the vehicle, and thought that it would be more preferable if the glare felt by the driver of the vehicle could be reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a technique for appropriately detecting reflected light from lighting of a vehicle.

A reflected light detection device according to an aspect of the present invention includes a visible light image obtained by imaging the outside of a vehicle illuminated by the lighting of the own vehicle with visible light, an infrared image obtained by imaging infrared rays from the imaging range of the visible light image, and visible light an acquisition unit that acquires distance information obtained by measuring the distance to an object included in the imaging range of the image; a specifying unit that specifies a specific region included in the imaging range of the visible light image that satisfies the condition that the distance is equal to or less than a third reference value; and an output that outputs a predetermined signal when the specific region is specified by the specifying unit. and

Another aspect of the invention is a reflected light detection method. This method includes a visible light image of the exterior of the vehicle illuminated by the lights of the vehicle, an infrared image obtained by capturing infrared light from the imaging range of the visible light image, and an object included in the imaging range of the visible light image. a step of obtaining distance information obtained by measuring a distance to an object; luminance in the visible light image is equal to or greater than a first reference value, luminance in the infrared image is equal to or less than a second reference value, and distance is equal to or less than a third reference value. and a step of outputting a predetermined signal when the specific region is identified.

It should be noted that arbitrary combinations of the above-described constituent elements and mutual replacement of the constituent elements and expressions of the present invention in methods, devices, systems, etc. are also effective as aspects of the present invention.

ADVANTAGE OF THE INVENTION According to this invention, the reflected light of the lighting of the own vehicle can be detected appropriately.

FIG. 4 is a diagram schematically showing how illumination light from the headlights of the own vehicle is reflected by an object in front; 1 is a block diagram schematically showing the functional configuration of a reflected light detection device according to an embodiment; FIG. It is a figure which shows a visible light image typically. It is a figure which shows an infrared image typically. FIG. 4 is a diagram schematically showing a method of specifying a specific region; 4 is a flow chart showing a reflected light detection method according to an embodiment;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. Specific numerical values and the like shown in these embodiments are merely examples for facilitating understanding of the invention, and do not limit the invention unless otherwise specified. In the present specification and drawings, elements having substantially the same functions and configurations are denoted by the same reference numerals to omit redundant description, and elements that are not directly related to the present invention are omitted from the drawings. do.

FIG. 1 is a diagram schematically showing how illumination light 52 of a headlight 32 of a vehicle 50 is reflected by an object in front. FIG. 1 shows a state in which the host vehicle 50 is approaching a forward vehicle 60 that is stopped for waiting at a traffic light or the like, and the host vehicle 50 is stopped. The illumination light 52 from the headlamp 32 is mainly incident on the rear portion of the forward vehicle 60, and is strongly reflected at a specific portion 62 (also referred to as a reflection portion). When the reflected light 54 from the specific point 62 is directed to the eyes of the driver 56, the driver 56 feels glare. Under such circumstances, the headlights 32 are temporarily turned off, the light intensity of the headlights 32 is temporarily reduced, or the headlights 32 are turned off so that the illumination light 52 does not enter the reflection point 62 . It is thought that the glare felt by the driver 56 can be reduced by changing the light distribution pattern.

This embodiment provides a technique that can reduce the glare felt by the driver 56 by appropriately detecting a situation in which the reflected light 54 of the lighting of the own vehicle 50 is dazzling. Specifically, based on the image captured by the visible light camera 22 and the infrared camera 24 provided on the vehicle 50 and the distance information measured by the distance sensor 26 provided on the vehicle 50, the reflected light 54 is dazzling. to detect.

FIG. 2 is a block diagram schematically showing the functional configuration of the reflected light detection device 10. As shown in FIG. Each functional block shown in the figure can be realized by hardware such as a computer CPU, memory, and other elements and mechanical devices, and is realized by software such as a computer program. It is drawn as a functional block to be realized. Therefore, those skilled in the art will understand that these functional blocks can be implemented in various ways by combining hardware and software.

The reflected light detection device 10 is connected to various devices mounted on the own vehicle 50 via an in-vehicle network 40 . A visible light camera 22, an infrared camera 24, a distance sensor 26, an in-vehicle sensor 28, a lighting control device 30, and the like are connected to the in-vehicle network 40. FIG. The in-vehicle network 40 is configured by CAN (Controller Area Network) or Ethernet (registered trademark), for example. Before describing the functional configuration of the reflected light detection device 10 in detail, peripheral devices will be described.

The visible light camera 22 is configured to capture an image of the surroundings of the own vehicle 50, for example, captures an image of the outside of the vehicle illuminated by the illumination light 52 of the headlamp 32 with visible light. Although the installation position of the visible light camera 22 does not matter, for example, the visible light camera 22 can be installed in the vicinity of the rear view mirror inside the vehicle. The visible light camera 22 may be a so-called drive recorder camera. The visible light camera 22 may be configured to capture only the exterior of the vehicle, or may be configured to capture both the exterior and interior of the vehicle.

The infrared camera 24 is configured to capture infrared rays from around the vehicle 50 and arranged to capture infrared rays from at least part of the imaging range of the visible light camera 22 . The infrared camera 24 is a so-called infrared thermography, which forms an image of the temperature distribution around the vehicle 50 so that heat sources existing around the vehicle 50 can be identified. The infrared camera 24 may be configured to detect mid-infrared rays with a wavelength of about 2 μm to 5 μm, or may be configured to detect far infrared rays with a wavelength of about 8 μm to 14 μm. Although the installation position of the infrared camera 24 does not matter, it can be installed near the front bumper of the own vehicle 50, for example. The infrared camera 24 is desirably provided outside the vehicle so that infrared rays from the heat source can be detected with high accuracy.

The distance sensor 26 measures the distance to objects existing around the vehicle 50 . An example of the distance sensor 26 is an ultrasonic sensor or a radar sensor, which is configured to measure the distance to an object included in the imaging range of the visible light camera 22 . Another example of the range sensor 26 is a LiDAR (Light Detection and Ranging), which is configured to acquire a range image of at least part of the imaging range of the visible light camera 22 . The installation position of the distance sensor 26 does not matter, but it can be installed, for example, near the front bumper of the own vehicle 50 or near the rearview mirror inside the vehicle. The distance sensor 26 may be provided in the vicinity of the visible light camera 22 or may constitute a sensor module integrated with the visible light camera 22 .

The in-vehicle sensor 28 is a device for acquiring information about the vehicle and information about the surrounding conditions of the vehicle. The in-vehicle sensor 28 includes, but is not limited to, an outside air temperature sensor, vehicle speed sensor, steering angle sensor, acceleration sensor, gyro sensor, position information sensor (GPS sensor), and the like.

The lighting control device 30 controls the operation of the headlights 32 of the own vehicle 50 . The lighting control device 30, for example, turns the headlights 32 on and off, and switches the headlights 32 between upward lighting (high beam) and downward lighting (low beam). The lighting control device 30 may be configured to be able to control at least one of the illumination range, illumination intensity, and illumination direction of the headlamps 32 . The illumination control device 30, for example, illuminates only a part of the illumination range that can be illuminated by the headlamps 32, moves the illumination direction of the illumination light 52 up, down, left, and right, and controls the illumination light. The illuminance of 52 may be changed stepwise.

Next, the functional configuration of the reflected light detection device 10 will be described in detail. The reflected light detection device 10 includes an acquisition unit 12 , an identification unit 14 , an extraction unit 16 and an output unit 18 .

The acquisition unit 12 acquires information about the surrounding situation of the own vehicle 50 . Acquisition unit 12 acquires a visible light image captured by visible light camera 22 , an infrared image captured by infrared camera 24 , and distance information measured by distance sensor 26 .

FIG. 3 is a diagram schematically showing a visible light image, and shows a visible light image obtained by imaging the front of the own vehicle 50 under the conditions shown in FIG. As shown, the visible light image includes the rear portion of the forward vehicle 60 and the traffic light 70, as well as the reflection portion 62 and the brake lamps 64L and 64R where the driver 56 feels glare. In the visible light image, the brake lamps 64L and 64R and the traffic signal 70 that are lit up, and the reflection point 62 where the illumination light 52 of the headlight 32 of the own vehicle 50 is strongly reflected are brightly captured.

FIG. 4 is a diagram schematically showing an infrared image, and shows an infrared image captured in front of the own vehicle 50 under the conditions shown in FIG. In an infrared image, a high-temperature portion that is a heat source is imaged brightly, but the heat detection sensitivity is inversely proportional to the square of the distance. Therefore, even a heat source appears dark in an infrared image when the distance from the own vehicle 50 is large. The lighted brake lamps 64L and 64R, the muffler 66 of the forward vehicle 60 from which the exhaust gas is discharged, and the like are shown brightly because they are close to the host vehicle 50. FIG. On the other hand, since the traffic light 70 is far from the host vehicle 50, it appears dark.

The specifying unit 14 specifies a “specific region” where the driver 56 is estimated to be feeling glare based on the image and the distance information acquired by the acquiring unit 12 . The identification unit 14 designates an area that satisfies the condition that the luminance of the visible light image is equal to or greater than the first reference value, the luminance of the infrared image is equal to or less than the second reference value, and the distance is equal to or less than the third reference value, as a “specific region”. Identify as In other words, the "specific area" is specified as a location where an object that is not a light source (heat source) such as a lamp but has a high visible light intensity and is located near (for example, within 5 m) the vehicle 50 is located.

When the imaging range (measurement range) or the angle of view of at least one of the visible light camera 22, the infrared camera 24, and the distance sensor 26 is different, the identification unit 14 performs correction processing so that the imaging targets (measurement targets) in the real space match. may be applied. For example, in the example shown in FIG. 1 , the visible light camera 22 and the distance sensor 26 are installed near the ceiling of the vehicle 50 , while the infrared camera 24 is installed near the bottom of the vehicle 50 . Therefore, correction processing may be performed on at least one of the visible light image and the infrared image so that the imaging range and the angle of view of the images captured by the visible light camera 22 and the infrared camera 24 match each other.

FIG. 5 is a diagram schematically showing a method of specifying a specific region. and the determination result of the traffic light 70. FIG. The reflected point 62 has high brightness in the visible light image, low brightness in the infrared image, and is close (approximately 2 m to 3 m) from the vehicle 50, and thus satisfies all of the above conditions. Therefore, the area where the reflection point 62 exists is identified as a "specific area".

On the other hand, the brake lamps 64L and 64R have high luminance in the visible light image and high luminance in the infrared image, so they are determined as areas where the light source exists. Since the muffler 66 has low luminance in the visible light image and high luminance in the infrared image, it is determined as an area in which a heat source other than a light source exists. Although the traffic light 70 has high brightness in the visible light image and low brightness in the infrared image, it is determined that it is not an area where glare is caused by the reflection of the illumination light of the vehicle 50 because the distance from the vehicle 50 is long. be done. Thus, the brake lamps 64L, 64R, the muffler 66 and the traffic light 70 do not satisfy all of the three conditions described above, so they are not identified as a specific area and become a "non-specific area". The winkers and back lamps of the forward vehicle 60 can also be determined as the "non-specific area" in the same manner as the brake lamps.

The specifying unit 14 may vary the first reference value according to the brightness around the vehicle. For example, in urban areas and places where there are many street lights that are bright even at night, the first reference value is set to a relatively large value. It may be set to a relatively small value. The specifying unit 14 may vary the first reference value based on the value of the illuminance sensor provided in the own vehicle 50, or may vary the first reference value based on the luminance of the visible light image acquired by the acquiring unit 12. good too.

The specifying unit 14 may vary the second reference value based on the temperature outside the vehicle. For example, in situations where the outside temperature is relatively high, such as in summer or during the day, the second reference value is set to a relatively large value, and in situations where the outside temperature is relatively low, such as in winter or at night, the second reference value The value may be a relatively small value. The specifying unit 14 can make the second reference value variable based on the measured value of an outside air temperature sensor provided in the own vehicle 50, for example.

The specifying unit 14 may vary the second reference value based on the difference in brightness of the acquired infrared image. For example, when the light sources of the brake lamps 64L and 64R are LEDs with low power consumption, and immediately after lighting, the temperature is relatively low and the brightness in the infrared image is low, making it difficult to extract the light source as the light source. It is conceivable that Therefore, a region with high brightness in the visible light image and relatively high brightness in the infrared image is regarded as a light source, and a predetermined value is subtracted from the brightness in the infrared image of the region regarded as the light source. value may be used as the second reference value. That is, the specific area may be specified based on the luminance difference (relative value) of each area in the infrared image. In this case, only a region judged to have a lower brightness (that is, a lower temperature) in the infrared image than the region regarded as the light source can be a candidate for the specific region.

Based on the visible light image acquired by the acquisition unit 12, the extraction unit 16 extracts an object included in the imaging range of the visible light image. The extraction unit 16 extracts a specific object from the visible light image using an image analysis technique such as pattern recognition. The extraction unit 16 extracts an object that may cause the driver 56 to feel glare due to the reflection of the illumination light 52 of the headlamp 32 . The extraction unit 16 extracts, for example, a vehicle in front, a reflector installed on a road surface, a guardrail, a wall surface of a parking lot, a road sign, etc., as objects.

When the specific region is specified by the specifying unit 14, the output unit 18 outputs a predetermined signal indicating that the driver 56 is feeling glare. The output unit 18 may output a predetermined signal only when the specific object extracted by the extraction unit 16 exists in the specific area specified by the specification unit 14 . For example, a predetermined signal may be output when the region determined by the extraction unit 16 to contain the vehicle ahead or the wall surface of the parking lot matches the specific region identified by the identification unit 14 .

The output unit 18 may output the control signal to the lighting control device 30 . The output unit 18 may output a control signal for changing at least one of the illumination range, illumination intensity, and illumination direction of the headlights 32 . The output unit 18 may output a signal for changing the irradiation range and irradiation direction so that the illumination light 52 is not irradiated toward the specific region (for example, the reflection location 62) specified by the specifying unit 14. The output unit 18 may output a signal for turning off the headlight 32 or reducing the illuminance of the headlight 32 . The output unit 18 outputs a control signal for changing at least one of the irradiation range, the irradiation illuminance, and the irradiation direction of the headlamp 32 so that the luminance of the specific region in the visible light image is less than the first reference value. may

The output unit 18 may output a predetermined signal only when the own vehicle 50 is stopped. For example, a control signal for changing at least one of the illumination range, illumination intensity, and illumination direction of the headlights 32 only when it is determined that the vehicle 50 is stopped based on information from the vehicle speed sensor. may be output. As a result, it is possible to prevent the lighting mode of the headlights 32 from changing while the host vehicle 50 is running. The output unit 18 may output a predetermined signal only when the vehicle speed of the own vehicle 50 is less than or equal to a predetermined speed. A predetermined signal may be output in this case.

The output unit 18 may cancel the output of the predetermined signal when the specific area is no longer specified, for example, when the distance to the object included in the specific area changes to a value exceeding the third reference value. . For example, when the forward vehicle 60 advances and the distance from the host vehicle 50 increases while waiting for a signal, the output of the predetermined signal may be canceled. Instead of canceling the output of the predetermined signal, the output unit 18 may output another signal indicating that the situation in which the driver 56 is feeling glare has been resolved.

FIG. 6 is a flow chart showing the reflected light detection method according to the embodiment. If the headlight 32 is on (Y of S10), a visible light image, an infrared image and distance information are acquired (S12). Based on the visible light image, the infrared image, and the distance information, the presence or absence of the specific area is determined, and if the specific area is identified (Y of S14), a predetermined signal is output (S16). If the headlight 32 is off (N of S10), the processing of S12 to S16 is skipped, and if the specific area is not specified (N of S14), the processing of S16 is skipped. The processing flow of FIG. 6 may be executed only when it is determined that the vehicle speed of the own vehicle 50 is stopped or when it is determined that the vehicle speed is equal to or less than a predetermined value.

According to the present embodiment, rather than simply specifying a dazzling area based on a visible light image, an area that is not a heat source is specified based on an infrared image, and an area close to the vehicle is specified based on distance information. Therefore, it is possible to precisely identify the area where the reflection of the illumination light 52 of the headlamp 32 is dazzling. Accordingly, it is possible to appropriately specify a situation in which glare can be controlled by changing the operation of the headlights 32 of the own vehicle, and to change at least one of the irradiation range, the irradiation illuminance, and the irradiation direction of the headlights 32. can reduce or eliminate glare. For example, it is possible to prevent inappropriate control such as changing the operation of the headlights 32 of the own vehicle 50 even though glare is caused by the lights of oncoming vehicles. Therefore, according to the present embodiment, it is possible to appropriately detect the reflected light of the lighting of the own vehicle 50 and take appropriate countermeasures.

Although the present invention has been described with reference to the above-described embodiments, the present invention is not limited to the above-described embodiments. is also included in the present invention.

In the above embodiment, the case of detecting the glare of the reflected light of the headlights of the own vehicle has been described. In a modified example, it may be configured to detect the glare of reflected light from auxiliary lights such as fog lamps provided in front or behind the own vehicle.

In the above embodiment, the case of detecting the driver's glare has been described. In a modified example, the method for specifying the specific area described above may be partially used to change the irradiation range and irradiation direction of the headlights while the vehicle is running. For example, when the headlights of an oncoming vehicle are detected and the operation of the headlights is controlled so that the high beam is not emitted toward the oncoming vehicle, the brightness of the visible light image is equal to or higher than the first reference value, and the infrared image may be specified as a candidate area in which an oncoming vehicle exists. On the other hand, a region in which the brightness of the visible light image is equal to or higher than the first reference value and the brightness of the infrared image is equal to or lower than the second reference value may be excluded from the candidate regions where the oncoming vehicle exists.

DESCRIPTION OF SYMBOLS 10... Reflected light detection apparatus, 12... Acquisition part, 14... Identification part, 16... Extraction part, 18... Output part, 22... Visible light camera, 24... Infrared camera, 26... Distance sensor, 30... Light control apparatus, 32... Headlight, 50... Own vehicle, 52... Illumination light, 54... Reflected light, 56... Driver, 60... Forward vehicle, 62... Reflection part.

Claims (6)

A visible light image obtained by capturing the exterior of the vehicle illuminated by the lights of the own vehicle with visible light, an infrared image obtained by capturing infrared rays from the imaging range of the visible light image, and an object included in the imaging range of the visible light image. an acquisition unit that acquires distance information obtained by measuring the distance of
The imaging range of the visible light image satisfies the conditions that the luminance in the visible light image is equal to or greater than a first reference value, the luminance in the infrared image is equal to or less than a second reference value, and the distance is equal to or less than a third reference value. a specifying part that specifies a specific region to be included;
Control for changing at least one of an irradiation range, an irradiation illuminance, and an irradiation direction of the lamp so that the luminance of the visible light image in the specific region specified by the specifying unit is less than the first reference value. and an output section for outputting a signal to the lighting control device. An extraction unit that analyzes the visible light image by pattern recognition and extracts an object included in the imaging range of the visible light image,
2. The reflected light detection device according to claim 1, wherein the output unit outputs the control signal when a specific object exists in the specific area. 3. The reflected light detection device according to claim 1, wherein the specifying unit varies the first reference value according to brightness outside the vehicle. The reflected light detection device according to any one of claims 1 to 3, wherein the specifying unit makes the second reference value variable according to the temperature outside the vehicle. the computer
A visible light image obtained by capturing the exterior of the vehicle illuminated by the lights of the own vehicle with visible light, an infrared image obtained by capturing infrared rays from the imaging range of the visible light image, and an object included in the imaging range of the visible light image. a step of obtaining distance information that measures the distance of
The imaging range of the visible light image satisfies the conditions that the luminance in the visible light image is equal to or greater than a first reference value, the luminance in the infrared image is equal to or less than a second reference value, and the distance is equal to or less than a third reference value. identifying specific regions of inclusion;
To change at least one of the irradiation range, the irradiation illuminance, and the irradiation direction of the lamp so that the luminance of the visible light image in the specific region is less than the first reference value when the specific region is specified. and outputting a control signal of to the control device of the lighting. A visible light image obtained by capturing the exterior of the vehicle illuminated by the lights of the own vehicle with visible light, an infrared image obtained by capturing infrared rays from the imaging range of the visible light image, and an object included in the imaging range of the visible light image. A function to acquire distance information obtained by measuring the distance of
The imaging range of the visible light image satisfies the conditions that the luminance in the visible light image is equal to or greater than a first reference value, the luminance in the infrared image is equal to or less than a second reference value, and the distance is equal to or less than a third reference value. the ability to identify specific regions of inclusion;
To change at least one of the irradiation range, the irradiation illuminance, and the irradiation direction of the lamp so that the luminance of the visible light image in the specific region is less than the first reference value when the specific region is specified. and a function of outputting a control signal to the lighting control device.

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