JP2009090844A - Lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting device capable of improving driver's visibility by controlling, for every small area, a lighting state of an area in front of a vehicle. <P>SOLUTION: The lighting device is provided with a visible light picturing part 12 and a near infrared picturing part 14 for picturing an area in front of the vehicle, a visible light lighting part 26 capable of lighting each small area formed by dividing the area in front of the vehicle into a plurality of small areas with different lighting state of visible light, a lighting intensity setting part 18 and a lighting control part 24 for controlling the visible lighting part 26 to bring a lighting state of each the small area in front of the vehicle for improving visibility of a front direction of the vehicle based on an image pictured by the visible light picturing part 12 and the near infrared picturing part 14. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an illumination device that illuminates the front of a vehicle.

Conventionally, various techniques have been proposed to improve the visibility of a vehicle driver. For example, a far-infrared stereo camera and a visible light stereo camera are provided, and the illumination direction of the headlamp is switched when the detected obstacle is outside the illumination area of the headlamp and within a predetermined area from the white line. A vehicle obstacle detection device that visibly illuminates the obstacle is known (see Patent Document 1). There has also been proposed a technique that includes a far-infrared camera, detects a pedestrian, and alerts the detected pedestrian by controlling and irradiating spot irradiation light (see Non-Patent Document 1).
JP 2000-318513 A Yohei Aragaki, 2 others, “Visual Assistance System Using Feature Point Density of Infrared Image”, 11th Image Sensing Symposium, E-8, 2005.6.

  However, in the above-described conventional technology, only the illumination target detected by a sensor or the like is illuminated, and the illumination state may not be a better illumination state simply by turning on / off the illumination. As a result, the visibility may be lowered as a result, for example, the overall contrast is lowered.

  An object of this invention is to provide the illuminating device which can improve a driver | operator's visibility more by controlling the illumination state of the area | region ahead of a vehicle for every small area | region.

  In order to achieve the above object, an illumination device according to claim 1 includes an imaging means for imaging a region in front of the vehicle, and visible light for each small region when the region in front of the vehicle is divided into a plurality of small regions. Based on the visible light illuminating means that can illuminate with different illumination states and the image obtained by imaging with the imaging means, the illumination state for each small area in front of the vehicle improves the visibility in front of the vehicle Control means for controlling the visible light illuminating means so as to be in an illuminating state.

  Thus, the visibility of the driver can be further improved by controlling the illumination state of the area in front of the vehicle for each small area based on the image captured by the imaging means.

  According to a second aspect of the present invention, regions where features that are characteristic of at least one of luminance and pattern are not similar to each other are adjacent to each other from the image obtained by imaging the control unit of the lighting device according to the first aspect with the imaging unit. The visible light illuminating means is controlled so that a difference in luminance between areas on both sides of the boundary is increased.

  Such control improves the contrast in front of the vehicle and improves the visibility of the illumination area in front of the vehicle. Note that the feature amount may be a value indicating an average value, a variance value, a texture, a luminance histogram, or the like of luminance values in a small region, for example.

  According to a third aspect of the present invention, the control means of the lighting device according to the first or second aspect is configured so that the illumination state for each of the small areas in front of the vehicle becomes an illumination state in which the visibility in front of the vehicle is improved. When the light illuminating means is controlled, the visible light illuminating means is controlled so that the luminance value for each of the small areas in front of the vehicle always becomes a predetermined value or more.

  According to such a configuration, the minimum brightness of the visual environment is guaranteed, so that necessary brightness can be ensured and visibility is improved.

  According to a fourth aspect of the present invention, an obstacle existing in a region in front of the vehicle is detected based on an image obtained by imaging the lighting device according to any one of the first to third aspects with the imaging unit. An obstacle detecting means for controlling the visible light illuminating means so that the illumination state for each of the small areas in front of the vehicle becomes an illumination state in which the visibility in front of the vehicle is improved. The visible light illumination unit is controlled so that the visibility of the obstacle detected by the obstacle detection unit is improved.

  According to such a configuration, the visibility of an obstacle that is an important object is improved.

  According to a fifth aspect of the present invention, there is provided the lighting device control means according to the fourth aspect, wherein the brightness difference between the obstacle area detected by the obstacle detection means and a background area other than the obstacle is increased. The visible light illumination means is controlled.

  Thereby, the visibility of the obstacle and the area in the vicinity thereof is improved in terms of contrast.

  According to a sixth aspect of the present invention, the imaging means of the lighting device according to any one of the first to fifth aspects of the present invention detects the far infrared rays emitted from the area in front of the vehicle and images the area in front of the vehicle. It is a thing.

  The invention of claim 7 further includes a near-infrared light irradiating means for irradiating a near-infrared light to the area in front of the vehicle in the illumination device according to any one of claims 1 to 5, wherein the imaging is performed. The means captures the front of the vehicle by receiving the reflected light of the near-infrared light irradiated to the area in front of the vehicle by the near-infrared light irradiation means.

  According to such a structure, since it can control to the illumination state which raises visibility more in the range where a driver | operator is hard to visually recognize, visibility improves in the whole vehicle forward visual field.

  According to an eighth aspect of the present invention, in the lighting device according to any one of the first to fifth aspects of the present invention, it is a time that is short enough that the driver and pedestrian of the vehicle existing in front of the vehicle are not dazzled, and Pulse light irradiating means is further provided for irradiating the area in front of the vehicle with visible light with a pulse width of a time during which the area in front of the vehicle can be imaged, and the imaging means is provided in the area in front of the vehicle by the pulse light irradiating means. The area in front of the vehicle is imaged when visible light having the pulse width is irradiated.

  According to such a configuration, the visibility is further improved in a range in which it is difficult for the driver to visually recognize based on the visible light image obtained by irradiating the front of the vehicle with a light amount that can be captured only by the imaging device without being dazzled. Since it can control to the lighting state to raise, visibility improves in the whole vehicle front visual field.

  A ninth aspect of the present invention is such that the imaging unit of the lighting device according to any one of the first to fifth aspects receives visible light reflected by a region in front of the vehicle, and images the front of the vehicle. An optical imaging means, and a far infrared imaging means for detecting the far infrared ray emitted from the area in front of the vehicle and imaging the area in front of the vehicle are configured and obtained by imaging with the visible light imaging means Based on the visible image and the far-infrared image obtained by imaging with the far-infrared imaging means, the luminance in the visible image is less than a first threshold and the luminance in the far-infrared image is greater than or equal to a second threshold. The low visual recognition area detecting means for detecting the low visual recognition area is further provided, and the control means is configured so that the illumination state of each small area in front of the vehicle is detected by the low visual recognition area detection means. Improved lighting conditions and It is obtained so as to control the visible light illumination means so that.

  According to such a configuration, the visibility of an area with poor visibility is improved.

  In a tenth aspect of the present invention, the imaging device of the lighting device according to any one of the first to fifth aspects receives visible light reflected by a region in front of the vehicle, thereby imaging the front of the vehicle. An imaging means and a near-infrared imaging means for imaging the front of the vehicle by receiving near-infrared light reflected by the area in front of the vehicle are configured, and near-infrared light is emitted in the area in front of the vehicle. The near-infrared light irradiating means for irradiating, the visible image obtained by imaging with the visible light imaging means, and the near-infrared light being irradiated to the area in front of the vehicle by the near-infrared light irradiating means. Low visibility based on a near-infrared image obtained by imaging with an infrared imaging means, wherein the luminance in the visible image is less than a first threshold and the luminance in the near-infrared image is greater than or equal to a second threshold A low visual recognition area detecting means for detecting the area; The control means controls the visible light illuminating means so that the illumination state of each of the small areas in front of the vehicle becomes an illumination state in which the visibility of the low visual recognition area detected by the low visual recognition area detection means is improved. It is what I did.

  According to such a configuration, the visibility of an area with poor visibility is improved.

  According to an eleventh aspect of the present invention, in the lighting device according to the eighth aspect, the first image and the pulse obtained by imaging with the imaging means when the pulsed light irradiating means does not irradiate visible light having the pulse width. Based on the second image obtained by imaging with the imaging means when the light irradiation means irradiates visible light with the pulse width, the luminance in the first image is less than a first threshold, and A low visual recognition area detecting means for detecting a low visual recognition area whose luminance in the second image is equal to or higher than a second threshold is further provided, and the control means is configured such that the illumination state of each small area in front of the vehicle is the low visual recognition area. The visible light illuminating means is controlled such that the visibility of the low visual recognition area detected by the detecting means is improved.

  According to such a configuration, the visibility of an area with poor visibility is improved.

  According to a twelfth aspect of the present invention, the imaging unit of the lighting device according to any one of the first to eleventh aspects captures the front of the vehicle by receiving visible light reflected by a region in front of the vehicle. In the case of including the visible light imaging means, the control means obtains a target luminance value for each small region so that the visibility ahead of the vehicle is improved, and is picked up by the visible light imaging means. On the basis of the visible image, the control amount of the visible light illuminating means is adjusted so that the luminance value of each small area in the area in front of the vehicle approaches the target luminance value.

  According to such a configuration, the actual illumination state and the target value can be compared to adjust the control amount of the visible light illumination means, so that the actual luminance value of the environment to be illuminated is brought close to the target luminance value. Can do.

  A thirteenth aspect of the present invention is the illumination device according to any one of the first to twelfth aspects, wherein the visible light illuminating means includes at least a light source that emits visible light, and a large number of liquid crystals that control transmission of light from the light source. A liquid crystal panel in which elements are arranged is included. .

  According to a fourteenth aspect of the present invention, the visible light illuminating means of the illuminating device according to any one of the first to twelfth aspects includes at least a light source that emits visible light, and a plurality of light reflection directions that control the light reflected from the light source. A reflection device in which reflection elements are arranged is configured.

  According to a fifteenth aspect of the present invention, the visible light illuminating means of the illuminating device according to any one of the first to twelfth aspects includes an LED light source in which a plurality of LED chips are arranged.

  By configuring the visible light illumination means in this way, it is possible to easily control the illumination state for each small area.

  The invention of claim 16 provides the visible light illuminating means and the near infrared light irradiating means of the illumination device according to any one of claims 7, 10, and 12 from near infrared light to visible light. The optical system includes a light source that emits light of a wavelength, a liquid crystal panel in which a large number of liquid crystal elements that control transmission of light from the light source are arranged, and a filter that partially blocks incident visible light.

  The invention of claim 17 provides the visible light illuminating means and the near infrared light irradiating means of the illumination device according to any one of claims 7, 10, and 12 from near infrared light to visible light. A light source that emits light of a wavelength, a reflection device in which a number of reflection elements that control the reflection direction of light from the light source are arranged, and an optical system that includes a movable filter that blocks transmission of incident visible light It is.

  According to such a configuration, since one optical system can be used as both the visible light illuminating unit and the near-infrared light irradiating unit, an illuminating device that can control visible light and near-infrared light with high spatial resolution is provided. It can be realized compactly.

  As described above, according to the illumination device of the present invention, the driver's visibility can be further improved by controlling the illumination state of the area in front of the vehicle for each small area. .

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of a lighting apparatus 10 according to the present embodiment.
Illumination device 10 of the present embodiment is mounted on a vehicle and has a visible light imaging unit 12, a near infrared imaging unit 14, a near infrared light irradiation unit 16, an illumination intensity setting unit 18, an obstacle detection unit 20, and visibility. An estimation unit 22, an illumination control unit 24, and a visible light illumination unit 26 are provided.

  The visible light imaging unit 12 receives visible light from an area in front of the vehicle and images the area in front of the vehicle. The near infrared imaging unit 14 receives near infrared light from a region in front of the vehicle and images the region in front of the vehicle. Note that the visible light imaging unit 12 and the near-infrared imaging unit 14 may be configured by a single imaging device. For example, a filter in which a visible light cut filter and a near-infrared light cut filter are alternately arranged is provided in the light receiving unit of the image pickup device, so that both a visible image and a near-infrared image can be captured with a single lens system. To do.

  The near-infrared light irradiation unit 16 is controlled by the illumination control unit 24 and irradiates a region in front of the vehicle with near-infrared light. The illumination intensity setting unit 18 uses the visible light illumination unit 26 based on the visible image obtained by the visible light imaging unit 12 and the near infrared image obtained by the near infrared imaging unit 14. Set the illumination intensity value when illuminating the front. The illumination control unit 24 controls the visible light illumination unit 26 based on the illumination intensity value set by the illumination intensity setting unit 18 and illuminates the area ahead of the vehicle with visible light.

  2A to 2C are diagrams illustrating a configuration example of the visible light illumination unit 26. The visible light illumination unit 26 shown in FIG. 2A is a liquid crystal projector type illumination device in which a lamp 40 as a light source and a large number of liquid crystal elements that control transmission of visible light received from the lamp 40 are arranged. A liquid crystal panel 42 and an objective lens 44 that forms an image of visible light transmitted through the liquid crystal panel 42 are provided. Each of a large number of liquid crystal elements provided in the liquid crystal panel 42 has a function of modulating the reflection / transmission state of incident light. When a voltage is applied, the electric field changes and the alignment of liquid crystal molecules changes. , Change the reflection / transmission state of incident light. Therefore, if the electric field is different for each liquid crystal element, visible light can be partially irradiated or blocked.

  2B is a mirror element projector type illumination device, and includes a lamp 46 as a light source and a number of reflecting elements that control the reflection direction of visible light received from the lamp 46. A mirror device 48 in which (mirrors) are arranged, and an objective lens 50 that forms an image of reflected light received from the mirror device 48 are provided. Each mirror of the mirror device 48 changes its tilt angle mechanically in response to an electrical input. Therefore, the reflection direction of the light incident on each mirror is selectively modulated by each mirror whose inclination angle is selectively changed.

  2C includes an LED array 52 in which a plurality of LED chips 51 are arranged, and a plurality of objective lenses 54 that image visible light emitted from the LED array 52. . The amount of light of each LED chip 51 can be varied by changing the amount of current and the current supply time for each LED chip 51.

  Note that the visible light illumination unit 26 of the present embodiment may have any of the configurations shown in FIGS. In any configuration, the illumination degree can be changed with high resolution with respect to the illumination space.

  The obstacle detection unit 20 provided in the illumination device 10 of the present embodiment is based on a near-infrared image obtained by being picked up by the near-infrared imaging unit 14 and is present in an area in front of the vehicle. Is detected. The detection result is output to the illumination intensity setting unit 18 and used for setting the illumination intensity value.

  In addition, the visibility estimation unit 22 has a luminance in the visible image based on the visible image obtained by being imaged by the visible light imaging unit 12 and the near-infrared image obtained by being imaged by the near-infrared imaging unit 14. A low visual recognition area (hereinafter referred to as an invisible area in the present embodiment) that is less than the first threshold T1 and whose luminance in the near-infrared image is equal to or higher than the second threshold T2 is detected. The detection result is output to the illumination intensity setting unit 18 and used for setting the illumination intensity value.

  Here, a detailed configuration of the illumination intensity setting unit 18 will be described. The illumination intensity setting unit 18 includes an image dividing unit 30, a luminance target value setting unit 32, a luminance feedback control unit 34, and an illumination intensity value setting unit 36.

  The image dividing unit 30 divides the near-infrared image obtained by being picked up by the near-infrared imaging unit 14 into small regions, obtains the degree of similarity with the adjacent small region for each divided small region, and is adjacent. Determine whether the region is continuous or discontinuous with respect to the small region. Based on the information on the small area obtained by the image dividing unit 30, the luminance target value setting unit 32 sets the luminance target for each small area so as to improve the visibility of the area in front of the vehicle in terms of brightness and contrast. Find the value. The luminance feedback control unit 34 compares the luminance target value for each small region obtained by the luminance target value setting unit 32 with the luminance value of the visible image actually captured by the visible light imaging unit 12, The comparison result is output to the illumination intensity value setting unit 36. The illumination intensity value setting unit 36 sets the illumination intensity value of the visible light illumination unit 26 and the illumination intensity value of the near infrared light irradiation unit 16. The illumination control unit 24 controls the illumination of the visible light illumination unit 26 and the near infrared light irradiation unit 16 with the illumination intensity value set by the illumination intensity value setting unit 36.

  Each component of the illumination intensity setting unit 18, the obstacle detection unit 20, the visibility estimation unit 22, and the illumination control unit 24 described above is realized by a computer that includes a CPU, a RAM, and a ROM. That is, the CPU executes the program stored in the ROM or a predetermined storage device, thereby realizing each of the above-described components, and performs the processing described later.

  Next, the operation of the present embodiment will be described on the assumption that the vehicle travels at night. In addition, as an example of an illuminated environment in front of the vehicle, as shown in FIG. 5 (A), there are two pedestrians on a paved road at night, and the pedestrian in the left front is located outside the street lighting. For example, the right back pedestrian is located in front of the street lighting. FIG. 5A shows an illuminated environment in which no visible light is illuminated from the vehicle.

  The illumination intensity value setting unit 36 sets a uniform illumination intensity value as an initial value in the irradiation range of a normal low beam (a state in which only the vicinity of the vehicle is illuminated with a small amount of light) with respect to the visible light illumination unit 26. For the infrared light irradiation unit 16, a uniform illumination intensity value is set in the irradiation range of the high beam (the state in which the entire field of view in front of the vehicle is illuminated with visible light). The irradiation with the low beam of visible light is the minimum illumination necessary for the vehicle to travel at night.

  The illumination control unit 24 controls the visible light illumination unit 26 and the near-infrared light irradiation unit 16 according to this set value, and irradiates visible light and near-infrared light.

  The visible light imaging unit 12 and the near-infrared imaging unit 14 respectively capture an illumination environment in front of the vehicle and generate a visible image and a near-infrared image. Hereinafter, specific examples of setting the illumination intensity value from the visible image and the near infrared image obtained by the visible light imaging unit 12 and the near infrared imaging unit 14 are shown in the flowcharts of FIGS. 3 and 4 and FIGS. A description will be given with reference to the processing example shown. Since the processing examples shown in FIGS. 6 to 8 are a series of processing, the description will be given with serial numbers in alphabetical order from (A) to (H) although they extend over different figure numbers.

  The illumination intensity setting unit 18 sets an illumination intensity value from the captured near-infrared image (see FIG. 6A) and visible image (see FIG. 6B).

  FIG. 3 is a flowchart showing the flow of the setting process of the illumination intensity value performed by the illumination intensity setting unit 18.

  In step 100, the image dividing unit 30 acquires a near-infrared image obtained by imaging by the near-infrared imaging unit 14 out of the two captured images. Since the near-infrared image is a captured image in the high beam region, the state of the entire vehicle front visual field can be grasped.

  In step 102, the image dividing unit 30 performs image division on the acquired near-infrared image. Here, the infrared image is divided into rectangular small areas having a predetermined size. FIG. 7C shows an example of division when the near-infrared image is divided into small regions.

  In step 104, a feature amount is calculated for each divided small area. The feature quantity to be obtained can be a value indicating an average value, a variance value, a texture, a brightness histogram, and the like of brightness values in a small area, for example. Next, for each small region, the similarity with the adjacent small region is obtained. This is obtained by comparing feature amounts of each small region and small regions adjacent to each small region. If the similarity is higher than a predetermined value, it is determined that the area is continuous with the adjacent small area. If the similarity is lower than the predetermined value, it is determined that the adjacent small area is a discontinuous area. When it is determined that the region is discontinuous, it can be said that the small region is a small region located at a boundary where adjacent regions having similar feature amounts are not adjacent to each other. FIG. 7D shows an example of a determination result obtained by determining whether the region is a continuous region or a discontinuous region. The determination result in the image dividing unit 30 is output to the luminance target value setting unit 32.

  Here, the image dividing unit 30 has described the example in which the near-infrared image is divided into a plurality of small regions having the same size, the similarity is obtained, and continuous or discontinuous is determined. The image processing is performed to determine the boundary of the object, the image is divided into a plurality of regions according to the boundary, the luminance feature amount of each region is determined, and continuous or discontinuous is determined. Good.

  In step 106, the luminance target value setting unit 32 acquires an obstacle detection result from the obstacle detection unit 20. The obstacle detection unit 20 acquires a near-infrared image and detects an obstacle present in the near-infrared image. An obstacle means an important visual recognition target, for example, another moving object such as a pedestrian or a roadside structure. As an obstacle detection method, a detection method based on an edge contour shape, a detection method based on a luminance pattern distribution, or the like can be used. FIG. 7E shows an example of the obstacle detection result.

  In step 108, the luminance target value setting unit 32 acquires the visibility estimation result from the visibility estimation unit 22. Here, the flow of the visibility estimation process performed by the visibility estimation unit 22 will be described in detail with reference to the flowchart of FIG.

  In step 120, a visible image obtained by imaging with the visible light imaging unit 12 and a near-infrared image obtained by imaging with the near-infrared imaging unit 14 are acquired.

  In step 122, the visibility estimation unit 22 initializes a counter k that counts the number of pixels. In step 124, the visibility estimation unit 22 calculates the visible light luminance L1 at the pixel D (k). In the next step 126, the visibility estimation unit 22 determines whether L1 is equal to or greater than T1. This T1 is a first threshold value, and is a threshold value for determining whether or not the area indicated by the pixel D (k) has brightness that can be visually recognized by the driver.

  If an affirmative determination is made in step 126, the pixel indicates that the driver can visually recognize, and in step 128, the visibility estimation unit 22 sets D (k) as a visible region.

  If a negative determination is made in step 126 (V is less than T1), in step 130, the visibility estimation unit 22 calculates the infrared light luminance L2 in the pixel D (k). In step 132, the visibility estimation unit 22 determines whether L2 is equal to or greater than T2. This T2 is a second threshold value and is a threshold value for determining whether or not the region indicated by the pixel D (k) can be recognized by near infrared light.

  If a negative determination is made in step 132, the pixel cannot be recognized with near-infrared light, and the driver cannot be visually recognized. In step 136, the visibility estimating unit 22 , D (k) is an invisible region.

  If an affirmative determination is made in step 132, the pixel is recognizable with near-infrared light and indicates that the driver cannot visually recognize. Therefore, in step 134, the visibility estimation unit 22 Let D (k) be an invisible region. As described above, the invisible region is a region where there is something that cannot be seen by the driver but can be recognized by near infrared light. The invisible area corresponds to a low visibility area having low visibility according to the present invention.

  Next, in step 138, k is incremented by one. In step 140, it is determined whether or not k exceeds the total number of pixels of the near-infrared image. This determination is a determination as to whether or not a process for determining an area has been executed for all pixels. If the determination is affirmative, there is a pixel that has not yet been defined, so the process of step 122 is executed again. If a negative determination is made, it indicates that an area has been defined for all pixels, and the process ends.

  The visibility estimation unit 22 thus detects the visible region, the invisible region, and the invisible region, and outputs information indicating the position of the invisible region to the luminance target value setting unit 32 as the visibility estimation result. To do.

  The acquisition timing of the obstacle detection result and the visibility estimation result is not limited to the above steps 106 and 108, and the luminance target value after the detection process of the obstacle detection unit 20 and the visibility estimation process of the visibility estimation unit 22 is obtained. Any time before setting the luminance target value by the setting unit 32 may be used.

  Next, in step 110 of FIG. 3, the luminance target value setting unit 32 determines the luminance target value of the area ahead of the vehicle based on the determination result of the continuous / discontinuous area, the obstacle detection result, and the visibility estimation result. calculate.

  The luminance target value setting unit 32 according to the present embodiment allows four levels (strong, medium, weak, and none) of setting values. For example, the brightness in the near-infrared image may be set to “medium”, and the intensity may be determined and set. The rule for setting the luminance target value is as follows.

1) The brightness of each small area is set to be equal to or higher than a predetermined minimum luminance value.

2) At the discontinuous boundary, there should be a sufficient luminance difference (contrast) in the regions on both sides of the boundary. In addition, there should be a sufficient brightness difference especially at the boundaries of areas detected as important obstacles. When an obstacle exists in the invisible area, the area is illuminated and a sufficient luminance difference is generated between the obstacle area and the background area.

3) In a portion where similar small areas are continuous, the luminance difference between the small areas is reduced.

The luminance target value setting unit 32 determines the luminance target value based on the above rule order.
Note that the minimum luminance value of rule 1 is a luminance value set in advance in the luminance target value setting unit 32 in order to guarantee the minimum brightness necessary for visual recognition.

  FIG. 8F shows a specific example of the set brightness target value. As shown in FIG. 8F, for the left front pedestrian, the luminance of the pedestrian area is increased to “strong”, and the luminance of the peripheral area that is discontinuous with the pedestrian area is “weak”. To lower. On the other hand, since the pedestrian on the right rear is located in front of the street lighting, the contrast is opposite to that of the pedestrian on the left front. Accordingly, the brightness of the pedestrian area is set to “weak” and the surrounding area is set to “strong”. The area of the entire road surface remains “medium” and is not brighter than necessary. Here, an example in which the value of the luminance target value is set in four stages has been described, but the present invention is not limited to this, and the luminance target value may be variable in an analog manner or only two values. The luminance target value setting unit 32 outputs the set luminance target value to the luminance feedback control unit 34.

  In step 112, the luminance feedback control unit 34 obtains a visible image obtained by the visible light imaging unit 12 (see FIG. 8G. Note that FIGS. 6B and 8G are the same). The luminance value of the visible image is compared with the luminance target value set by the luminance target value setting unit 32. Then, the luminance feedback control unit 34 obtains an illumination target value that is a target value of the illumination intensity value of the visible light illumination unit 26 for each small region from the comparison result, and outputs the illumination target value to the illumination intensity value setting unit 36. (First step of feedback control). Further, in the luminance feedback control unit 34, the illumination intensity value setting unit 36 continues to acquire the visible image captured in the illumination state with the illumination target value set as the illumination intensity value, and the luminance value of the visible image and the luminance target are obtained. The brightness target value set by the value setting unit 32 is compared. If the luminance target value is approaching but the luminance is insufficient, a higher illumination target value is maintained.If the visible light image does not change even when the illumination is changed, the illumination target value is maintained or a lower illumination target value is selected. If the values are close to each other but the brightness is high, lower illumination target values are set, and the illumination target values are output to the illumination intensity value setting unit 36 (second step of feedback control).

  For example, as shown in FIG. 8 (G), street illumination exists in the vicinity of the right rear pedestrian, and has sufficient luminance even if no visible light is emitted from the vehicle. Therefore, the illumination target value (first step of feedback control) obtained by the luminance feedback control unit 34 with respect to this region is an illumination target value in a direction that maintains or lowers the current illumination target value. Also, it is not possible to uniquely determine how much the amount of illumination needs to be increased in order to obtain a visible image that is the target brightness value, such as when the brightness of the visible image is insufficient with respect to the target lighting value. With the illumination target value (second step of feedback control) obtained by the control unit 34, the luminance of each small area can be brought close to the luminance target value.

  In step 114, the illumination intensity value setting unit 36 sets the illumination intensity value of the visible light illumination unit 26 for each small area based on the illumination target value feedback-controlled by the luminance feedback control unit 34. Here, the value of the illumination target value is set as the illumination intensity value.

  FIG. 8H shows an example of the set final illumination intensity value. Here, the illumination intensity value is also a value of four levels (strong, medium, weak, and none), similar to the luminance target value. The illumination intensity value setting unit 36 outputs the set illumination intensity value to the illumination control unit 24. The illumination control unit 24 controls the visible light illumination unit 26 according to the illumination intensity value, and controls the irradiation amount of visible light over the entire vehicle front visual field by adjusting the light amount for each small region.

  Thereby, as shown in FIG. 5C, the illumination intensity shown in FIG. 5A is adjusted for the pedestrian and the background so that the visibility is improved in terms of brightness contrast. Visibility is improved. In the example shown in FIG. 5C, as described above, for the pedestrian on the left front, the entire road surface is not brightened more than necessary, the luminance around the pedestrian is suppressed, Visible illumination improves contrast and improves visibility. In addition, the right and left pedestrians have the same background and background brightness as that of the left front, so the contrast of the pedestrians can be improved by reducing the lighting of the pedestrians and increasing the background brightness. I am letting.

  FIG. 5B shows an illumination example when the visible light is simply irradiated so as to uniformly increase the luminance of the dark part of the visible image as a comparative example. The brightness of the pedestrian area is increased and the visibility is improved compared to the case without lighting, but the left front pedestrian has a high road surface brightness, and the right rear pedestrian has a high background brightness. Visibility has not been improved.

  In the present embodiment, the example in which the feedback control is uniformly performed by the luminance feedback control unit 34 has been described. However, the effect of the feedback control is verified, and if the effect is not achieved, the control is stopped, or the current state You may perform control which reduces illumination intensity on the conditions that a luminance value does not fall.

  One optical system may be used as both the visible light illumination unit 26 and the near infrared light irradiation unit 16. FIG. 9A is a diagram illustrating a configuration example of the illumination unit 68 capable of emitting both visible light and near infrared light. The illumination unit 68 includes a light source 60 that emits light having a wavelength from visible light to near-infrared light, a liquid crystal panel 62 in which a number of liquid crystal elements that control transmission of incident light from the light source 60 are arranged, and transmission of visible light. A mosaic type visible light cut filter 64 in which a filter to be blocked is partially disposed, and an objective lens 66 that forms an image of visible light transmitted through the liquid crystal panel 62 are provided.

  FIG. 10A is a diagram illustrating an example of the mosaic-type visible light cut filter 64. As shown in FIG. 10A, in the mosaic type visible light cut filter 64, filters 64a that block transmission of near-infrared light and filters 64b that block transmission of visible light are alternately arranged. When the illumination unit 68 emits visible light, the illumination control unit 24 allows each pixel of the liquid crystal panel 62 so that the light from the light source 60 enters only the region of the filter 64a that blocks transmission of near-infrared light. Control on / off. When the illumination unit 68 irradiates near infrared light, on / off of each pixel of the liquid crystal panel 62 is controlled so that light from the light source 60 is incident only on a region of the filter 64b that blocks transmission of visible light. . By controlling the liquid crystal panel 62 in this way, visible light and near-infrared light can be emitted from one illumination unit 68. Here, the filter 64a for blocking the transmission of near-infrared light is provided, but this filter 64a is not provided, and the portion where the filter 64a is arranged is configured to transmit the incident light of all wavelengths. May be. This is because near-infrared light is invisible light, so that even if it is irradiated simultaneously with visible light, the visibility is not affected.

  Further, FIG. 9B shows another example in which the visible light illumination unit 26 and the near infrared light irradiation unit 16 are configured by one optical system. In the illumination unit 78, a light source 70 that emits light having a wavelength from visible light to near infrared light, and a filter that blocks transmission of visible light are partially arranged, and the entire unit rotates to transmit the visible light. The rotary visible light cut filter 72 whose filter position to be blocked fluctuates, the mirror device 74 in which a number of reflecting elements (mirrors) for controlling the reflection direction of incident light are arranged, and the reflected light received from the mirror device 48 is imaged. An objective lens 76 is provided.

  FIG. 10B is a diagram illustrating an example of the rotary visible light cut filter 72. As shown in FIG. 10B, the rotary visible light cut filter 72 includes a filter 72a that blocks transmission of near-infrared light and a filter 72b that blocks transmission of visible light. The rotary visible light cut filter 72 is configured to be rotatable about a rotation shaft 72c. When the illumination control unit 24 irradiates visible light with the illumination unit 78, the rotary visible light is arranged such that a filter 72a that blocks transmission of near-infrared light is disposed between the light source 70 and the mirror device 74. The cut filter 72 is rotated. Further, when the illumination control unit 24 irradiates near infrared light with the illumination unit 78, the illumination control unit 24 rotates so that a filter 72 b that blocks transmission of visible light is disposed between the light source 70 and the mirror device 74. The visible light cut filter 72 is rotated. By controlling the rotary visible light cut filter 72 in this way, visible light and near infrared light can be emitted from one illumination unit 78. Here, the filter 72a for blocking the transmission of near-infrared light is provided. However, the filter 72a is not provided, and the portion where the filter 72a is arranged is configured to transmit the incident light of all wavelengths. May be.

  Thus, the illuminating device 10 can be reduced in size by comprising the visible light illumination part 26 and the near-infrared light irradiation part 16 by one optical system.

  In the above embodiment, an example in which the illumination intensity setting unit 18 includes the image dividing unit 30, the luminance target value setting unit 32, the luminance feedback control unit 34, and the illumination intensity value setting unit 36 has been described. For example, the luminance feedback control unit 34 may not be provided. In such a configuration, the illumination intensity value setting unit 36 sets the illumination intensity value using the luminance target value obtained by the luminance target value setting unit 32 as it is. This also improves the visibility compared with the conventional lighting device, but in order to realize better visibility without providing the luminance feedback control unit 34, the characteristics and appearance of the near-infrared image and the visible image in advance. Is obtained in advance based on a test image or the like, stored in some memory, and in illumination control for illuminating visible light, a correction process for correcting the luminance target value so as to eliminate the difference with reference to the memory is performed. You may make it perform.

  Moreover, it is good also as a structure which does not provide the obstruction detection part 20 and the visibility estimation part 22 in the illuminating device 10. FIG. Without considering the presence or absence of obstacles or whether the visibility is good or not, simply dividing the image and determining whether it is continuous or discontinuous and obtaining the brightness target value will result in the same contrast and brightness. Visibility is improved as compared with a device that uniformly illuminates visible light without consideration.

  Furthermore, instead of the near-infrared imaging unit 14, for example, a far-infrared imaging unit that detects far-infrared radiation emitted from a region in front of the vehicle and images the entire field of view in front of the vehicle may be provided. The far-infrared imaging unit uses the characteristic that far-infrared rays are emitted from an object having heat, and therefore does not need to irradiate light having a wavelength other than visible light. Also by this, it is possible to image an area that cannot be visually recognized, and to obtain a luminance target value as in the above embodiment.

  Moreover, as an imaging means, it is set as the structure which provides only the visible light imaging part 12 and does not provide the near-infrared imaging part 14, and also in a short time so that the driver and pedestrian of the vehicle which exist in front of a vehicle may not be dazzled. In this case, the visible light imaging unit 12 irradiates pulsed light with pulsed visible light to a region ahead of the vehicle (in this case, the high beam region is irradiated instead of the low beam of course) with a pulse width of a time during which the region ahead of the vehicle can be imaged. A portion may be provided.

  Thereby, a visible light image of the area ahead of the vehicle is obtained by irradiating visible light in a state where the driver or pedestrian of the vehicle is not dazzled. Using this visible light image in the same manner as the near-infrared image of the above embodiment, a luminance target value is obtained and an illumination intensity value is set. In this case, since it is not necessary to consider the difference in characteristics between the near-infrared image and the visible light image, sufficient visibility can be ensured even if the feedback control described above is omitted.

  Moreover, although the said embodiment demonstrated the example which provides the visible light imaging part 12 and the near-infrared imaging part 14, images a visible light image and a near-infrared image, and controls visible light illumination, visibility As long as the estimation unit 22 and the luminance feedback control unit 34 are not provided, the visible light imaging unit 12 may not be provided, and only the near-infrared imaging unit 14 or the far-infrared imaging unit may be provided. The visible light imaging unit 12 and the pulse irradiation unit described above may be provided without the outer imaging unit 14 or the far infrared imaging unit, and a visible image may be captured. Even with such a configuration, the luminance target value setting unit 32 obtains the luminance target value for each small area and the illumination intensity value setting unit 36 sets the illumination intensity in the same manner as described above. Improves.

It is a block diagram which shows schematic structure of the illuminating device which concerns on embodiment of this invention. (A)-(C) are figures which show the structural example of a visible light illumination part. It is a flowchart which shows the flow of the setting process of the illumination intensity value which an illumination intensity setting part performs. It is a flowchart which shows the flow of the visibility estimation process performed in a visibility estimation part. (A) is a figure which shows the to-be-illuminated environment in the state in which visible light is not illuminated at all from a vehicle, (B) is the case where visible light is irradiated so that the brightness | luminance of the dark part of a visible image may only be raised It is an example of illumination and (C) is a figure which shows the example of illumination at the time of illuminating with the illuminating device of this Embodiment. (A) is a figure which shows the example of the near-infrared image imaged with the near-infrared imaging part 14, (B) is a figure which shows the example of the visible image imaged with the visible light imaging part. (C) is a figure which shows the example of a division | segmentation when a near-infrared image is divided | segmented into a small area, (D) is a figure which shows the example of a judgment result which judged whether it was a continuous area | region or a discontinuous area | region. (E) is a figure which shows the example of an obstruction detection result. (F) is a figure which shows the example of the set brightness | luminance target value, (G) is a figure which shows the example of the imaged visible image, (H) is set from (F) and (G) It is a figure which shows the example of the done illumination intensity value. It is a figure which shows the structural example of the illumination part which can irradiate both visible light and near-infrared light. (A) is a figure which shows an example of a mosaic type | mold visible light cut filter, (B) is a figure which shows an example of a rotation type visible light cut filter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Illumination device 12 Visible light imaging part 14 Near infrared imaging part 16 Near infrared light irradiation part 18 Illumination intensity setting part 20 Obstacle detection part 22 Visibility estimation part 24 Illumination control part 26 Visible light illumination part 30 Image division part 32 Luminance target value setting unit 34 Luminance feedback control unit 36 Illumination intensity value setting unit

Claims (17)

Imaging means for imaging an area in front of the vehicle;
Visible light illuminating means capable of illuminating by varying the illumination state of visible light for each small area when the area in front of the vehicle is divided into a plurality of small areas;
Based on the image obtained by imaging with the imaging means, the visible light illumination means is controlled so that the illumination state of each small region in front of the vehicle becomes an illumination state in which the visibility in front of the vehicle is improved. Control means;
Including lighting device. The control means obtains a boundary where areas having similar features that are characteristic of at least one of luminance and pattern are adjacent to each other from an image obtained by imaging with the imaging means, and between the areas on both sides of the boundary The illuminating device according to claim 1, wherein the visible light illuminating means is controlled so that the luminance difference becomes large. The control means controls the visible light illuminating means so that the illumination state of each small area in front of the vehicle becomes an illumination state in which the visibility in front of the vehicle is improved. The illuminating device according to claim 1 or 2, wherein the visible light illuminating unit is controlled so that a luminance value for each unit always exceeds a predetermined value. Based on an image obtained by imaging with the imaging means, further comprising an obstacle detection means for detecting an obstacle present in the area in front of the vehicle,
The control means is detected by the obstacle detection means when controlling the visible light illumination means so that the illumination state of each small region in front of the vehicle becomes an illumination state in which visibility in front of the vehicle is improved. The illuminating device according to claim 1, wherein the visible light illuminating unit is controlled so that the visibility of the obstruction is improved. The lighting device according to claim 4, wherein the control unit controls the visible light illuminating unit such that a luminance difference between an obstacle area detected by the obstacle detection unit and a background area other than the obstacle is increased. . The lighting device according to claim 1, wherein the imaging unit detects far infrared rays emitted from a region in front of the vehicle and images the region in front of the vehicle. Further comprising a near infrared light irradiating means for irradiating the region in front of the vehicle with near infrared light,
The said imaging means images the said vehicle front by receiving the reflected light of the near infrared light irradiated to the area | region ahead of the said vehicle by this near infrared light irradiation means. The lighting device described. Visible light is emitted to the area in front of the vehicle with a pulse width of a time that is short enough that the driver and pedestrian of the vehicle existing in front of the vehicle are not dazzled and can capture the area in front of the vehicle with the imaging means. It further comprises pulsed light irradiation means for performing pulse irradiation,
The illumination according to any one of claims 1 to 5, wherein the imaging unit images the region in front of the vehicle when visible light having the pulse width is irradiated onto the region in front of the vehicle by the pulsed light irradiation unit. apparatus. The imaging means detects visible light imaging means for imaging the front of the vehicle by receiving visible light reflected by the area in front of the vehicle, and far infrared rays emitted from the area in front of the vehicle to detect the vehicle It is configured to include a far infrared imaging means for imaging a front area,
Based on the visible image obtained by imaging with the visible light imaging means and the far-infrared image obtained by imaging with the far-infrared imaging means, the luminance in the visible image is less than a first threshold, and A low visual recognition area detecting means for detecting a low visual recognition area whose luminance in the far-infrared image is equal to or higher than a second threshold;
The control means controls the visible light illuminating means so that the illumination state of each small area in front of the vehicle becomes an illumination state in which the visibility of the low visual recognition area detected by the low visual recognition area detection means is improved. The illuminating device of any one of Claims 1-5. The imaging means receives visible light reflected from the area in front of the vehicle to receive the visible light imaging means for imaging the front of the vehicle, and receives near-infrared light reflected from the area in front of the vehicle. Comprising near-infrared imaging means for imaging the front of the vehicle,
Near-infrared light irradiating means for irradiating near-infrared light to a region in front of the vehicle;
Visible image obtained by imaging with the visible light imaging means and obtained by imaging with the near infrared imaging means with the near infrared light irradiating means irradiating the area in front of the vehicle with near infrared light A low-visibility region detection means for detecting a low-visibility region in which the luminance in the visible image is less than a first threshold and the luminance in the near-infrared image is greater than or equal to a second threshold based on the near-infrared image Further comprising
The control means controls the visible light illuminating means so that the illumination state of each small area in front of the vehicle becomes an illumination state in which the visibility of the low visual recognition area detected by the low visual recognition area detection means is improved. The illuminating device of any one of Claims 1-5. The first image obtained by imaging with the imaging unit when the pulsed light irradiating unit does not irradiate visible light with the pulse width, and the irradiating unit with the pulsed width visible light with the pulsed light irradiating unit. Low visual recognition based on the second image obtained by imaging with the imaging means, wherein the luminance in the first image is less than the first threshold and the luminance in the second image is greater than or equal to the second threshold Further comprising a low visual recognition area detecting means for detecting an area,
The control means controls the visible light illuminating means so that the illumination state of each small area in front of the vehicle becomes an illumination state in which the visibility of the low visual recognition area detected by the low visual recognition area detection means is improved. The lighting device according to claim 8. In the case where the imaging means is configured to include visible light imaging means for imaging the front of the vehicle by receiving visible light reflected by the area in front of the vehicle,
The control means obtains a target luminance value for each small area so that visibility in front of the vehicle is improved, and each of the areas in front of the vehicle is determined based on a visible image captured by the visible light imaging means. The illuminating device according to any one of claims 1 to 11, wherein a control amount of the visible light illumination unit is adjusted so that a luminance value for each small region approaches the target luminance value.   The said visible light illumination means is comprised including the liquid crystal panel which arranged the light source which emits at least visible light, and many liquid crystal elements which control permeation | transmission of the light from this light source. The lighting device described.   The said visible light illumination means is comprised including the reflection apparatus which arranged the light source which emits at least visible light, and many reflective elements which control the reflection direction of the light from this light source. The lighting device according to item.   The illumination device according to claim 1, wherein the visible light illumination unit includes an LED light source in which a plurality of LED chips are arranged. A liquid crystal panel in which the visible light illuminating means and the near infrared light irradiating means are arranged with a light source that emits light having a wavelength from near infrared light to visible light, and a large number of liquid crystal elements that control transmission of light from the light source. The illumination device according to any one of claims 7, 10, and 12, comprising: an optical system including a filter that partially blocks incident visible light. Reflection in which the visible light illuminating unit and the near infrared light irradiating unit are arranged with a light source that emits light having a wavelength from near infrared light to visible light, and a plurality of reflective elements that control the reflection direction of light from the light source. The illuminating device according to any one of claims 7, 10, and 12, comprising: an apparatus; and an optical system including a movable filter that blocks transmission of incident visible light.