JP4867761B2 - Night vision support device - Google Patents

Description

  The present invention relates to a night vision assistance device, and more particularly to a night vision assistance device that assists a driver's vision by irradiating infrared rays in front of a vehicle when traveling at night.

  When a vehicle such as an automobile travels at night, the driver performs a driving operation while visually confirming that there are no obstacles in the light irradiation range from the headlamp. When using a low beam, it is difficult to see distant obstacles and pedestrians. In view of this, near infrared light is emitted in front of the light irradiation range from the headlamp (low beam), and an image in front of the vehicle captured by the near infrared camera is displayed, thereby assisting the driver's field of view during night driving. Development of a night vision support device is underway. Since near-infrared light cannot be seen by humans, it can be irradiated in front of the light irradiation range from the headlamp (low beam) without hindering the operation of oncoming vehicles. In addition, near infrared rays have a longer wavelength than visible light and are difficult to scatter. Therefore, even when the field of view cannot be opened due to rain or fog, it is easy to image an obstacle in front of the vehicle.

  However, if the image in front of the vehicle captured by the near-infrared camera is displayed as it is, when a light source such as a headlight of an oncoming vehicle is captured in the image, a part of the image is displayed white due to the influence of halation. Therefore, it becomes difficult to identify the presence or absence of a pedestrian or an obstacle in the image.

Ingenuity has already been devised to eliminate such inconveniences. For example, an image is corrected so that a pixel whose luminance is higher than that of the pixel corresponding to the obstacle has a luminance value lower than that of the pixel corresponding to the obstacle. A vehicle image correction device has been proposed (see, for example, Patent Document 1). Further, a near-infrared camera in which the exposure time of the near-infrared camera is fixed to a value that can suppress the influence of halation has been proposed (for example, see Patent Document 2).
JP 2003-199094 A JP 2004-153425 A

  However, the vehicular image device described in Patent Document 1 can suppress the influence of halation by correcting the near-infrared camera image, but improves the amount of near-infrared light incident on the near-infrared camera from a pedestrian or obstacle. It is impossible to improve the brightness of pedestrians and obstacles in the near-infrared camera image.

  Moreover, although the near-infrared camera of patent document 2 can suppress the influence of halation by shortening the exposure time of a near-infrared camera, the near-infrared light quantity which injects into a near-infrared camera from a pedestrian or an obstacle is The brightness of the image of a pedestrian or an obstacle in the near-infrared camera image decreases.

  The present invention has been made in view of the above, and can suppress the influence of halation, can improve the amount of near-infrared light incident on the near-infrared camera from a pedestrian or an obstacle, and can walk in the near-infrared camera image. An object of the present invention is to provide a night vision support device capable of improving the brightness of an image of a person or an obstacle.

In order to achieve the above object, the present invention provides:
An infrared lamp that emits infrared light in front of the vehicle; an infrared camera that receives infrared light from the front of the vehicle and outputs an image signal; and an image display device that displays the image signal output from the infrared camera as an image. In the night vision support device equipped with
High-luminance area determination means for determining a high-luminance area in which the luminance of pixels of an image displayed by the image display device is equal to or higher than a predetermined threshold;
The infrared light that irradiates the front of the vehicle corresponding to an area other than the high-luminance area when the amount of light of the infrared lamp that irradiates the front of the vehicle corresponding to the high-luminance area determined by the high-luminance area determination means An infrared lamp control means for controlling the infrared lamp so as to be lower than the light quantity of the lamp ,
The infrared lamp control means includes
Vehicle speed determination means for determining whether the speed of the vehicle is equal to or higher than a predetermined value;
An infrared condensing means for condensing an infrared irradiation area from the infrared lamp in a vehicle width direction;
When the vehicle speed determining means determines that the speed of the vehicle is equal to or higher than a predetermined value, the infrared light collecting means condenses the infrared irradiation area from the infrared lamp in the vehicle width direction. To do .

According to the present invention, it is possible to make the distribution of the amount of near-infrared light incident on the near-infrared camera from the front of the vehicle uniform. As a result, the influence of halation can be suppressed, the amount of near-infrared light incident on the near-infrared camera from pedestrians and obstacles can be improved, and the brightness of pedestrian and obstacle images in infrared camera images can be improved. The driver can easily identify pedestrians and obstacles in the infrared camera image.

Further, according to the present invention, during high-speed travel, by condensing the near-infrared irradiation region from near infrared lamp in the vehicle width direction, near the distal (forward irradiation range of the headlamp (low beam)) amount of near infrared rays increases entering the infrared camera, can improve the identification of distant pedestrians and obstacles can be performed with confidence high speed.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing the configuration of an embodiment of a night vision support device and its peripheral devices according to the present invention. As shown in FIG. 1, the night vision support device receives a near-infrared lamp 10 that irradiates near-infrared light in front of a light irradiation region from a headlamp 1 (low beam) and near-infrared light from the front of the vehicle. A near-infrared camera 20 that outputs an image signal, an image display device 30 that displays an image signal output from the near-infrared camera 20 as an image, and an ECU 40 (Electrical Control Unit) are provided. Details of the ECU 40 will be described later. When traveling at night, the driver operates the vehicle while visually confirming the region irradiated with visible light from the headlamp 1 (low beam) and viewing the image displayed by the image display device 30.

  The near-infrared lamp 10 irradiates only near-infrared rays forward by a filter that cuts visible light. The near-infrared light emitted from the near-infrared lamp 10 has a wavelength (780 nm to 1500 nm) in a region that is not perceived by human eyes. Since it does not feel, it can irradiate ahead of the vehicle without hindering the operation of the oncoming vehicle. In addition, near infrared rays have a longer wavelength than visible light and are less likely to scatter. Therefore, even when the field of view cannot be opened due to rain or fog, it is easy to capture an image of an obstacle in front of the vehicle.

  The near-infrared camera 20 has a lens portion attached to the front of the vehicle from the inside of the windshield, and is provided near the ceiling of the vehicle so as to receive near-infrared light from the front of the vehicle. The near-infrared camera 20 captures an image of the object based on the difference in reflectance of near-infrared light reflected from the object irradiated with near-infrared light. Accordingly, when the near-infrared light amount emitted from the near-infrared lamp 10 to the front of the vehicle decreases, the near-infrared light received by the near-infrared camera 20 becomes dark, and the image displayed by the image display device 30 becomes dark.

  The image display device 30 uses, for example, a head-up display. The head-up display is attached to the upper surface of the meter in front of the driver's seat, and projects an image obtained from an image signal output from the near-infrared camera 20 (hereinafter referred to as a near-infrared camera image) onto the inner surface of the windshield.

  2A and 2B are diagrams schematically showing a display example of a near-infrared camera image captured by a conventional night vision support device. FIG. 2A is a diagram showing an image during normal night driving, and FIG. It is a figure which shows the image of the state which approached. (C) is a top view of the state of (B).

  As shown in FIG. 2A, during normal night driving, the pedestrian enters the near-infrared camera 20 as compared to the near-infrared light amount incident on the near-infrared camera 20 from the road or background. Since the amount of near-infrared light is high, the driver can identify a pedestrian in the near-infrared camera image. In FIG. 2A, in order to clarify the positional relationship of pedestrians, the road lane is expressed in white. However, in an actual near-infrared camera image, the road lane is close to the road lane. Imaging is performed according to the amount of near-infrared light incident on the infrared camera 20.

  As shown in FIG. 2 (B), when an oncoming vehicle approaches (see FIG. 2 (C)), if the exposure time of the near infrared camera 20 is set to be relatively short in order to suppress the influence of halation, a pedestrian The amount of near-infrared light incident on the near-infrared camera 20 becomes low, and the pedestrian image in the infrared camera image becomes dark. As a result, it becomes difficult for the driver to identify a pedestrian in the infrared camera image.

  As shown in FIG. 2C, the near-infrared lamp 10 irradiates near-infrared rays in front of a light irradiation range from a headlamp (low beam).

  The night vision support device is connected to a light sensor 2 including a photoelectric conversion element that receives a light amount around the vehicle and outputs a signal corresponding to the light amount, and detects a sunset, night, or dawn by a detection signal from the light sensor 2. The ECU 40 that turns on the headlamp 1 is provided when it is a dark time zone in which the amount of light from the sun is reduced.

  As the ECU 40, a microcomputer can be used. As shown in FIG. 1, a headlamp 1, a light sensor 2, a headlamp switch 3 for turning the headlamp 1 on and off, a vehicle speed sensor 5, and a windshield Turn on / off the window wiper Turn on the window wiper switch 6, near infrared lamp 10, near infrared camera 20, image display device 30, near infrared lamp 10, etc. (near infrared lamp 10, near infrared camera 20, image display device 30) -The night vision support mode switch 4 to be turned off is connected by wire or wirelessly. Further, the ECU 40 is determined by a high luminance area determination unit 50 that determines a high luminance area in which the luminance of the pixel of the image displayed by the image display device 30 is equal to or higher than a predetermined threshold, and the high luminance area determination unit 50. The near-infrared lamp 10 so that the light amount of the near-infrared lamp 10 that irradiates the front of the vehicle corresponding to the high-luminance region is lower than the light amount of the near-infrared lamp 10 that irradiates the front of the vehicle corresponding to the region other than the high-luminance region. And a near-infrared lamp control means 60 for controlling. The near-infrared lamp control means 60 has a light quantity of the near-infrared lamp 10 that irradiates the front of the vehicle corresponding to the high-luminance area determined by the high-luminance area determination means 50, in front of the vehicle corresponding to an area other than the high-luminance area. The near-infrared lamp light quantity control means 61 for controlling the near-infrared lamp 10 to be lower than the light quantity of the near-infrared lamp 10 that irradiates and the area of the high-intensity area determined by the high-intensity area determination means 50 is a predetermined value or more. High brightness region area determining means 70 for determining whether or not, vehicle speed determining means 80 for determining whether or not the speed of the vehicle is equal to or greater than a predetermined value, and a near infrared irradiation area from the near infrared lamp 10 are collected in the vehicle width direction. The near-infrared light collecting means 81 that emits light, the precipitation determination means 90 that determines whether the precipitation around the vehicle is equal to or greater than a predetermined value, and the near-infrared irradiation area from the near-infrared lamp 10 Composed of near infrared irradiation area moving means 91. which moves in the width direction.

  Here, processing executed by the ECU 40 will be described with reference to the flowcharts of FIGS. 3 and 4.

  The ECU 40 checks whether or not the headlamp switch is turned on in S11 of FIG. If the headlamp switch is off in S11, the process proceeds to S12 to check whether the light sensor is on. If the light sensor is off in S12, the ambient brightness is sufficient due to sunlight, and the process returns to S11.

  In S11, when the driver turns on the headlamp switch, or in S12, when it is detected by the light sensor that the amount of light from the sun has decreased, such as sunset, night, or dawn, S13. Proceed to In S13, the headlamp is turned on.

  Subsequently, in S14, it is checked whether or not the night vision support mode switch is turned on. In S14, when the night vision support mode switch is not turned on, the process returns to S11, and the processes after S11 are performed. In S14, when the night vision assistance mode switch is turned on, the night vision assistance mode is entered, and in S15, the image display device 30 is switched to the image display state. At this time, the luminance of the image displayed on the image display device 30 is suppressed to 10% of the maximum value.

  Subsequently, in S16, it is checked whether or not the vehicle speed V of the vehicle is accelerated to exceed a predetermined speed Va. The predetermined speed Va is set to 30 km / h, for example. When the vehicle speed V is not accelerated to exceed the predetermined speed Va in S16, the process proceeds to S17, and it is checked whether or not the vehicle has stopped. If the vehicle is not stopped in S17, the process returns to S15. If the vehicle is stopped in S17, the process proceeds to S18, the image display device 30 is switched to the OFF state, and the process returns to S11.

  In S16, if the vehicle speed V is accelerated to exceed the predetermined speed Va, the process proceeds to S19, and the near infrared lamp 10 is turned on to irradiate the front of the vehicle with near infrared light. Subsequently, in S20, the near-infrared camera 20 is turned on and imaging in front of the vehicle is started.

  Next, in S21 shown in FIG. 4, the brightness of the image displayed on the image display device 30 is increased to the set brightness. As a result, the image signal output from the near-infrared camera 20 is output to the head-up display (image display device 30) via the ECU 40, and the head-up display (image display device 30) displays the near-infrared camera image on the windshield. Project inside. Therefore, the driver confirms the presence or absence of obstacles by visually observing the area irradiated with visible light from the headlamp, and the near infrared camera displayed by the head-up display in front of the area irradiated with visible light. The presence or absence of pedestrians and obstacles can be confirmed with images.

  In S22, it is checked whether or not the vehicle speed V is accelerated to a specified speed Vb or higher. The specified speed Vb is specified at a higher speed than Va described above, and is, for example, 80 km / h. When the vehicle speed V is equal to or higher than the specified speed Vb, the process proceeds to S23, and after condensing the near infrared irradiation area from the near infrared lamp 10 in the vehicle width direction, the process proceeds to S24. The near-infrared light collected from the near-infrared lamp 10 is obtained by condensing the near-infrared light from the near-infrared lamp 10 with a prism, or the distance between the light source of the near-infrared lamp 10 and the reflection cover of the near-infrared lamp 10. It can be realized by changing. The near-infrared light amount incident on the near-infrared camera 20 from the front of the irradiation range of the headlamp (low beam) by condensing the near-infrared irradiation region from the near-infrared lamp 10 on the own lane of the vehicle when traveling at high speed. As a result, the identities of distant pedestrians and obstacles can be improved, and high speed driving can be performed with peace of mind. If the vehicle speed V is less than the specified speed Vb in S22, S23 is skipped and the process proceeds to S24.

Subsequently, in S24, it is checked whether or not the amount of precipitation around the vehicle is equal to or greater than a specified amount. The determination of the precipitation around the vehicle according to the present embodiment is made based on whether the window wiper switch 6 is turned on or off. When the window wiper switch 6 is turned on, it is determined that the precipitation around the vehicle is equal to or more than a specified amount. When the window wiper switch 6 is on, the process proceeds to S25, and after moving the near-infrared irradiation area from the near-infrared lamp 10 from the opposite lane of the vehicle to the own lane, the process proceeds to S26. The movement of the near-infrared irradiation region from the near-infrared lamp 10 can be performed by refracting near-infrared light with a prism, or by changing the direction of the near-infrared lamp 10 in the vertical and horizontal directions. Ru can be realized by controlling the gear mechanism by an electric motor. If the window wiper switch 6 is off in S24, S25 is skipped and the process proceeds to S26.

  Subsequently, in S26, a high luminance area in which the luminance L of the pixel of the infrared camera image is equal to or higher than a predetermined threshold La is determined, and the process proceeds to S27. The determination of the high luminance area is performed by, for example, sequentially scanning the scanning line from the left to the right in the infrared camera image and reading the coordinates of the pixels in the continuous high luminance area on the scanning line. In the next S27, the area of the high luminance region is obtained. For example, the area of the high-brightness area is calculated by sequentially scanning the scanning line from left to right in the infrared camera image and sequentially adding the number of pixels in the continuous high-brightness area on the scanning line.

  Subsequently, in S28, it is checked whether or not the area S of the high luminance region has expanded beyond a predetermined value Sa. In S28, when it is determined that the area S of the high brightness area has expanded to the predetermined value Sa or more, the process proceeds to S29, and the light amount of the near infrared lamp 10 that irradiates the front of the vehicle corresponding to the high brightness area is high brightness. The near-infrared lamp 10 is controlled to be lower than the amount of light of the near-infrared lamp 10 that irradiates the front of the vehicle corresponding to an area other than the area. In this way, by controlling the near-infrared lamp 10, the distribution of the near-infrared light amount incident on the near-infrared camera 20 from the front of the vehicle can be made closer to the uniform.

  FIG. 5 is a schematic diagram of a near-infrared camera image obtained by capturing the state of FIG. 2B with the night vision support device of the present embodiment. Compared with FIG. 2 (B), when the night vision assistance device of the present embodiment is used, the influence of halation can be suppressed and the amount of near infrared light incident on the near infrared camera 20 from a pedestrian can be improved. The brightness of the pedestrian image in the infrared camera image can be improved. As a result, the driver can easily identify the pedestrian in the near-infrared camera image.

  For example, when the near-infrared lamp 10 is composed of a plurality of near-infrared LEDs, the near-infrared lamp 10 is turned off by turning off the near-infrared LED that irradiates near-infrared light in front of the vehicle corresponding to the high-luminance region. This can be done by turning on near-infrared LEDs that emit near-infrared rays in front of the vehicle corresponding to areas other than the brightness area. Alternatively, the near-infrared lamp 10 is controlled by an electric motor that refracts near-infrared light with a prism, or a gear mechanism that can freely change the direction of the vertical axis and the horizontal axis of the near-infrared lamp 10. This can be achieved.

  Further, when it is determined in S28 that the area S of the high brightness area has not expanded beyond the predetermined value Sa, or after the near-infrared lamp 10 is controlled in S29, the process proceeds to S30, where the vehicle speed V is less than the specified speed Vc. Check if the vehicle has slowed down. The specified speed Vc is specified to be lower than the aforementioned Va (Vc <Va).

  In S30, when the vehicle speed V is not less than the specified speed Vc, the process returns to S22, and the processes after S22 are performed. In S30, when the vehicle speed V is less than the specified speed Vc, the process proceeds to S31 to check whether or not the vehicle has stopped. In S31, when the vehicle is traveling at a low speed without stopping, the process returns to S22 described above, and the processes after S22 are performed.

  In S31, when the vehicle stops, the process proceeds to S32, and it is checked whether or not the headlamp switch 3 is turned off. If the headlamp switch 3 is on in S32, the process proceeds to S33, and it is checked whether the light sensor 2 is off. If the light sensor 2 is on in S33, the process returns to S22, and the processes after S22 are performed again.

  In S32, when the driver turns off the headlight switch 3, or in S33, the light sensor 2 detects that the surrounding brightness is not a sufficient amount of light, the process proceeds to S34. In S34, the headlamp 1, the near-infrared lamp 10, the near-infrared camera 20, and the image display device 30 are turned off and the current process is terminated.

  Thus, when the high-intensity area where the luminance of the pixel of the near-infrared camera image is equal to or greater than the predetermined threshold is equal to or greater than the specified area, the light amount of the near-infrared lamp 10 that irradiates the front of the vehicle corresponding to the high-intensity area. By controlling the near-infrared lamp 10 so as to be lower than the light amount of the near-infrared lamp 10 that irradiates the front of the vehicle corresponding to a region other than the high-luminance region, the amount of near-infrared light incident on the near-infrared camera 20 from the front of the vehicle Can be made to be uniform. As a result, the influence of halation can be suppressed and the amount of near-infrared light incident on the near-infrared camera 20 from a pedestrian or obstacle can be improved, so that the identities of pedestrians and obstacles in the near-infrared camera image are improved. it can.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

  For example, although the high-intensity area determination unit of the present embodiment uses a near-infrared camera image, a near-infrared light sensor fixed in front of the vehicle toward the oncoming lane may be used. In this case, when the amount of light received by the near-infrared light sensor is greater than or equal to a predetermined value, it is determined that the area of the image corresponding to the area of the oncoming lane is a high luminance area.

  In addition, the high luminance area area determination means of this embodiment determines whether or not the area of the high luminance area is equal to or greater than a predetermined value (S27). However, as long as the light source of the high luminance area is a headlight of an oncoming vehicle, Since the luminance region has a shape in which two circles partially overlap each other, the distance between the centers of the circles of the high luminance region can be used as an area index instead of the area. Specifically, the scanning line is sequentially scanned from left to right in the near-infrared camera image, and from the first position where the number of pixels in the continuous high-intensity area on the scanning line is maximized, the continuous high on the scanning line. The distance to the second position where the number of pixels in the luminance region is minimized and maximized again can be used as an area index.

  The near-infrared lamp control means of this embodiment controls on / off of the near-infrared LED, but controls the voltage of the near-infrared LED according to the area and brightness of the high-intensity region, and the light quantity of the near-infrared LED Can also be controlled continuously.

It is the block diagram which showed the structure of one Example of the night vision assistance apparatus which concerns on this invention, and its peripheral device. It is a figure which shows typically the example of a display of the near-infrared camera image imaged with the conventional night vision assistance apparatus. It is the flowchart which showed an example of the process which ECU40 performs. FIG. 4 is a flowchart showing an example of processing executed by an ECU 40 following the processing of FIG. 3. It is a schematic diagram of the near-infrared camera image which imaged the state of FIG. 2 (B) with the night vision assistance apparatus of a present Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Near-infrared lamp 20 Near-infrared camera 30 Image display apparatus 40 ECU
DESCRIPTION OF SYMBOLS 50 High-intensity area | region determination means 60 Infrared lamp control means 61 Infrared lamp light quantity control means 70 High-intensity area | region area determination means 80 Vehicle speed determination means 81 Near-infrared condensing means 90 Precipitation amount determination means 91 Near-infrared irradiation area movement means

Claims (2)

An infrared lamp that emits infrared light in front of the vehicle; an infrared camera that receives infrared light from the front of the vehicle and outputs an image signal; and an image display device that displays the image signal output from the infrared camera as an image. In the night vision support device equipped with
High-luminance area determination means for determining a high-luminance area where the luminance of pixels of an image displayed by the image display device is equal to or higher than a predetermined threshold;
The infrared light that irradiates the front of the vehicle corresponding to an area other than the high-luminance area when the amount of light of the infrared lamp that irradiates the front of the vehicle corresponding to the high-luminance area determined by the high-luminance area determination means An infrared lamp control means for controlling the infrared lamp so as to be lower than the light quantity of the lamp ,
The infrared lamp control means includes
Vehicle speed determination means for determining whether the speed of the vehicle is equal to or higher than a predetermined value;
An infrared condensing means for condensing an infrared irradiation area from the infrared lamp in a vehicle width direction;
When the vehicle speed determining means determines that the speed of the vehicle is equal to or higher than a predetermined value, the infrared light collecting means condenses the infrared irradiation area from the infrared lamp in the vehicle width direction. night vision assist apparatus for. The infrared lamp control means includes
High brightness area determination means for determining whether the area of the high brightness area determined by the high brightness area determination means is a predetermined value or more;
The infrared light that irradiates the front of the vehicle corresponding to an area other than the high-luminance area when the amount of light of the infrared lamp that irradiates the front of the vehicle corresponding to the high-luminance area determined by the high-luminance area determination means An infrared lamp light quantity control means for controlling the infrared lamp so as to be lower than the lamp light quantity,
Claim 1, characterized in that performing the high-by luminance region area determining means when the area of the high luminance region is determined to be equal to or greater than the predetermined value, the control of the infrared lamp by the infrared lamp light quantity control unit The night vision support device described in 1.

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