JP2008164537A - Adhesive detection device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect an adhesive on a light source without providing an exclusive sensor or the like, concerning a floodlight of a vehicle or the like. <P>SOLUTION: An adhesive detection device includes a floodlighting means 110 capable of floodlighting light, a floodlighting control means 120 for controlling the floodlighting means so that floodlighting and non-floodlighting are performed almost simultaneously, an imaging means 130 for imaging an image relative to an imaging object in a range into which light is floodlighted from the floodlighting means at each of a floodlighting time and a non-floodlighting time, and determination means 160, 180 for determining whether an adhesive exists on the floodlighting means by comparing mutually a floodlighting time brightness which is a brightness of an image imaged at the floodlighting time with a brightness of an image imaged at the non-floodlighting time. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technical field of an adhering matter detection apparatus and method for detecting dirt or snow adhering to, for example, a projector.

  As this kind of adhering matter detection device, there is a device that includes a light source and a sensor that detects light, and detects adhering matter based on the intensity of light detected by the sensor. For example, in a vehicle such as an automobile, a technique for detecting raindrops or the like from an image obtained by photographing a wind screen is known. (See Patent Document 1).

  On the other hand, there is a technique in which the surrounding situation can be grasped even in a dark place by illuminating the surroundings using an infrared projector, photographing the image with an infrared camera, and displaying the image as an image. For example, in a vehicle such as an automobile, a technique is known that supports driving in a dark situation such as nighttime by showing a driver an image taken using infrared rays. (See Patent Document 2).

JP 2005-531752 A Japanese Patent Application Laid-Open No. 2004-254044

  However, in the technology using infrared rays as described above, the infrared rays cannot be directly visually recognized. Therefore, even if the irradiated infrared rays are weakened due to, for example, dirt attached to the infrared projector, the user There is a technical problem that there is a possibility that the situation cannot be recognized. On the other hand, it is possible to detect the weakening of the infrared rays due to the adhesion of such dirt by a sensor for monitoring the intensity of the infrared rays arranged near the infrared projector, but in this case, a dedicated sensor must be separately received. There is a big disadvantage.

  The present invention has been made in view of, for example, the above-described problems, and an object thereof is to provide a deposit detection apparatus and method that can detect deposits on a light source without providing a dedicated sensor or the like.

  In order to solve the above-described problem, the attached matter detection apparatus of the present invention projects a light projecting unit capable of projecting light and a light projecting unit that controls the light projecting unit so that light projecting and non-light projecting are performed before and after. A control unit; an imaging unit that captures an image of an object within a range in which light is projected by the light projecting unit at each of the light projection time and the non-light projection time; and Whether there is any deposit on the light projecting means by comparing the brightness at the time of projection, which is the brightness of the captured image, with the brightness at the time of non-projection, which is the brightness of the image captured at the time of non-projection Determination means for determining whether or not.

  According to the adhering matter detection apparatus according to the present invention, during the operation, the light projecting unit is first controlled by the light projecting control unit, so that light projecting and non-light projecting are performed in succession. For example, in principle, the light projection may be performed at all times, and the non-light projection may be performed temporarily when the adhering matter is determined. And the image which concerns on the to-be-photographed object in the range where light is projected by the imaging means is imaged about each of light projection and non-light projection. Here, in particular, when an adhering substance adheres to the light projection control means, the brightness of the image to be captured with respect to the same light projection at the time of light projection is lower than when no adhering substance is attached. For this reason, the relative brightness at the time of projection compared with the brightness at the time of non-lighting should be smaller when the deposit is attached. On the contrary, the relative brightness at the time of light projection compared with the brightness at the time of non-light should be larger when no deposit is attached. In other words, if an adhering substance such as dirt adheres to the light projecting means, the brightness at the time of light projection is reduced by the amount that blocks the light from the light projecting means, and the difference from the brightness at the time of non-light projection should be reduced. Therefore, the light projecting means is obtained by comparing the projected brightness that is the brightness of the image captured at the time of projection with the non-projected brightness that is the brightness of the image captured at the time of non-projected light. It is determined whether or not there is any deposit on the surface. Such an adhering matter detection operation may be set to be automatically executed at predetermined intervals, for example, or may be executed in response to pressing a switch for executing the determination. May be executed.

  The brightness at the time of projection and the brightness at the time of non-projection are, for example, the brightness of the whole image or each pixel constituting the image, the brightness of each pixel block made up of a plurality of pixels, the brightness of the whole frame image, and these are added temporally. It is possible to determine by various methods such as brightness when stored. In order to accurately compare these luminances, it is desirable that the objects to be imaged (for example, landscapes and roads) at the time of projection and at the time of non-projection are the same or at least partially the same. In any case, the relative brightness at the time of light projection compared to the brightness at the time of non-lighting is smaller when the adhered matter is attached, and is larger when the attached matter is not attached.

  In the present invention, in particular, since an adhering matter is detected based on an image picked up by the image pickup means, it is not necessary to separately provide a sensor such as a photodiode for detecting light projected from the light projecting means. . That is, in the case where an imaging means (for example, a camera used for obtaining an ambient image) used for purposes other than the detection of the attached matter is provided, the attached matter in the light projecting means is used. Can be detected. Therefore, since it is not necessary to use new parts such as a sensor, it is possible to detect the deposit on the light projecting means while reducing or preventing an increase in cost.

  In one aspect of the adhering matter detection device of the present invention, the determination unit calculates a difference between the luminance at the time of projection and the luminance at the time of non-projection, and when the calculated difference is smaller than a predetermined threshold, It is determined that there is a deposit.

  According to this aspect, the difference between the brightness at the time of projection, which is the brightness of the image at the time of projection, and the brightness at the time of non-projection, which is the brightness of the image at the time of non-projection, is calculated by the determination means. When the difference is smaller than the predetermined threshold value, it is determined that the deposit is present on the light projecting means.

  A decrease in the difference between the brightness at the time of projection and the brightness at the time of non-projection indicates that the intensity of light projected by the light projecting means is reduced. For this reason, it is possible to consider that there are deposits such as dirt on the light projecting means, blocking the light from the light projecting means. In addition to the adhering matter in the light projecting means, for example, the light from the light source in the light projecting means may decrease due to the lifetime of the light source, etc. Conceivable. However, the probability and degree of the decrease in the light intensity due to such a cause is very low as compared with the case where the deposit is caused by the light projecting means. Therefore, it is possible to determine whether or not the deposit is present on the light projecting means by a relatively simple method of obtaining the difference between the brightness at the time of projection and the brightness at the time of non-projection.

  In the above-described aspect in which it is determined that the deposit is present on the light projecting unit when the difference between the luminance values is smaller than the predetermined threshold, the light projecting control unit performs the light projecting and the non-light projecting alternately. The light projecting unit is controlled, the image capturing unit sequentially captures the images, the determination unit sequentially calculates the difference, and the state in which the sequentially calculated difference is smaller than the predetermined threshold is greater than a predetermined time. When it continues for a long time, you may comprise so that it may determine with the said deposit | attachment existing.

  If comprised in this way, a light projection means will be controlled by the light projection control means first, and light projection and non-light projection will be performed alternately. And the image at the time of light projection and the time of non-light projection is sequentially imaged by the imaging means. Next, the difference between the luminance at the time of projection and the luminance at the time of non-projection is sequentially calculated from the captured image. For example, when two images, a projected image and a non-projected image are captured, the difference between the projected luminance and the non-projected luminance is calculated from the two images, and thereafter Such processing is repeated. Then, a state where the difference between the calculated luminance at the time of projection and the luminance at the time of non-projection is smaller than a predetermined threshold continues for longer than the predetermined time (in other words, the difference between the luminance at the time of projection and the luminance at the time of non-projection) Is smaller than a predetermined value for a predetermined number of times), it is determined that the deposit is present on the light projecting means. That is, the difference between the brightness values suddenly becomes smaller than a predetermined value when an object not attached to the light projecting means obstructs the light projecting path, or due to noise such as sensor output or spikes. In this case, it can be determined that there is no deposit on the projector.

  As described above, by excluding the case where the difference in luminance value instantaneously becomes smaller than the predetermined threshold value, an erroneous determination is made, for example, when noise temporarily enters the captured image. This can be prevented. Therefore, it is possible to improve the accuracy of detection of adhered matter of the apparatus.

  In another aspect of the adhering matter detection apparatus of the present invention, the imaging means captures a plurality of images as the image at the time of light projection and at the time of non-light projection, and the determination means includes the light projection. Calculating a projection parameter indicating a predetermined statistical value related to the luminance at the time of projection based on a plurality of images captured at times, and the luminance at the time of non-projection based on the plurality of images captured at the time of non-projection By calculating a non-light-projecting parameter indicating the predetermined statistical value according to the above, and comparing the calculated light-projecting parameter and the non-light-projecting parameter with each other, the light-projecting luminance and the non-light-projecting luminance Are compared with each other.

  According to this aspect, a plurality of images are picked up by the image pickup means at the time of projecting and at the time of non-projecting. In the determination means, a projection parameter indicating a predetermined statistical value related to the luminance at the time of projection is calculated from a plurality of images at the time of projection. Similarly, a non-projection parameter indicating a predetermined statistical value related to the non-projection brightness is calculated from a plurality of non-projection images. Here, the “predetermined statistical value” according to the present invention refers to an average value (that is, average luminance), a variance value (that is, luminance variance), a standard deviation, a cumulative value or an added value, a maximum value, or a plurality of images. It means a predetermined kind of statistical value such as a maximum value, minimum value or minimum value, median value, cumulative value for the remainder excluding the maximum value or minimum value, an added value, or an average value. Further, it may be a statistical value such as the cumulative value or the average value described above in a pixel unit or a pixel block unit composed of a plurality of pixels. In any case, any parameter indicating the statistical values of a plurality of images can be used.

  And at the time of light projection, the parameter at the time of light projection which shows the statistical value regarding the brightness | luminance at the time of light projection is calculated with respect to each time or each period corresponding to a some image. At the time of non-projection, a non-projection parameter indicating a statistical value related to the non-projection brightness is calculated for each time or each period corresponding to a plurality of images. Then, by comparing the calculated projection parameter and the non-projection parameter with each other, the projection luminance and the non-projection luminance are compared with each other, and whether there is any deposit on the projection means. A determination is made whether or not.

  As described above, by calculating a new parameter using a plurality of images, it is possible to statistically determine whether or not there is a deposit. Therefore, it is possible to detect the adhering substance with higher accuracy than when only one image is used during light projection and during non-light projection.

  In another aspect of the attached matter detection apparatus of the present invention, the light projecting means can project light other than visible light as the light.

  According to this aspect, light other than visible light such as infrared light is projected from the light projecting means. The light projecting means may be capable of projecting visible light simultaneously or separately with light other than visible light.

  Assuming that the light projected from the light projecting means is visible light, since the drop of the projected light can be recognized by the human eye, for example, the projected light is blocked by an adhering substance or the like. When the strength is reduced, the user of the device can directly visually recognize it, and can take some measures at that time. However, when projecting light other than visible light, that is, visually unrecognizable light, even if the light intensity is reduced, it cannot be recognized by a person who is directly looking at the light projection range. That is, even when the intensity of the light projecting means is reduced due to the attached matter or the like, there is a risk that the device will continue to be used without being noticed and with a low light projecting effect.

  However, in the present invention, in particular, since it is possible to detect whether or not the deposit on the light projecting unit is present using the image captured by the image capturing unit, it is a problem whether or not the light to be projected is visible light. Don't be. Therefore, for example, even if the light to be projected is light other than visible light such as infrared rays, it is possible to determine whether or not there is a deposit by comparing images captured by the infrared camera. it can.

  In addition, when light other than visible light is projected, humans cannot directly recognize the light, so there is a high possibility that an imaging unit for recognizing the light is provided in advance. That is, it is not necessary to separately provide the imaging means in the present invention, and the increase in cost can be reduced or prevented. The projected light may include visible light in addition to light other than visible light. In this case, the projected light is, for example, light in which visible light and infrared light are combined. It becomes.

  As described above, when light other than visible light is projected from the light projecting means, the effect of the adhering matter detection device according to the present invention is more remarkable than when light of visible light is projected. Will be.

  In another aspect of the adhering matter detection apparatus of the present invention, the light projecting means includes a light emitting diode.

  According to this aspect, since the light projecting means includes the light emitting diode, for example, compared with an incandescent lamp, the response time when switching between light projection and non-light projection is short. Images can be captured in a short period of time when there is no light projection.

  By capturing images continuously in a short time, it is possible to suppress the objects to be imaged from greatly differing between the image at the time of projection and the image at the time of non-projection. Accordingly, since the images can be compared more accurately at the time of light projection and at the time of non-light projection, it is possible to improve the detection accuracy of the attached matter. In addition, since the light emitting diode has a light emitting area smaller than that of, for example, an incandescent lamp, the luminance is significantly reduced when an adhering material adheres. For this reason, the basic function in the present invention which tries to avoid inconvenience in the case of adhesion by detecting the adhesion of the deposit as described above is very useful.

  In another aspect of the adhering matter detection apparatus of the present invention, the adhering matter detection apparatus further includes an ambient condition detecting unit that detects an ambient condition of the adhering matter detection device, and the determination unit is the ambient condition detected by the ambient condition detecting unit. In the predetermined situation, it is determined whether or not an adhering substance is present on the light projecting means.

  According to this aspect, the surrounding state of the deposit detection device is detected by the surrounding state detection unit. Then, only when the detected surrounding situation is a predetermined situation, it is determined whether or not the deposit is present on the light projecting means in the judging means. Here, the predetermined situation is a situation set in advance using a parameter such as brightness, and a plurality of parameters may be used at this time.

  The surrounding state detection means is, for example, a brightness sensor, and is set to detect the surrounding brightness of the attached matter detection device and to determine the attached matter if the brightness is equal to or lower than a predetermined brightness. If the surroundings of the device are bright, there are no deposits on the light projecting means, and even if the light is normally projected, when comparing the brightness information of the image, when light is projected and when not The difference between and is not noticeable. That is, the detection accuracy of the apparatus may be reduced.

  However, in the present invention, in particular, the adhering matter is determined only when the brightness around the apparatus is equal to or lower than a predetermined brightness. Therefore, when the light is normally projected from the light projecting means, the light is projected. A significant difference appears in the luminance information between the time image and the non-light-projected image. Therefore, more accurate detection can be performed.

  The ambient condition detection means is, for example, a speed sensor, and is set so as to detect the speed of the movable deposit detection device and determine the deposit if the speed is equal to or lower than a predetermined speed. For example, when the object detection device is movable, such as when the object detection device is mounted on a vehicle or a vehicle, the object to be imaged by the imaging means is projected and unprojected during the movement. May be very different from each other. As described above, the objects to be imaged at the time of light projection and at the time of non-light projection are preferably the same or at least partially the same. For this reason, it is better that the moving speed of the apparatus when imaging is slow.

  Here, particularly in the present invention, the deposit is determined only when the speed of the apparatus is equal to or lower than a predetermined speed. In other words, when the speed is high and there is a possibility that the objects to be imaged at the time of projection and at the time of non-projection are greatly different from each other, it is possible to prevent the determination of the attached matter. Therefore, it is possible to prevent the determination unit from making an erroneous determination due to the different objects to be imaged at the time of light projection and at the time of non-light projection. Therefore, it is possible to improve the accuracy of detecting the deposit on the apparatus.

  As described above, it is possible to improve the detection accuracy of the adhering matter by performing the determination by the determination unit only when the surrounding state is a predetermined state. Even if the determination by the determination means is not performed because the surrounding situation is not a predetermined condition, it is possible to use the light projecting means and the imaging means for purposes other than the detection of the attached matter. It is.

  In order to solve the above-mentioned problem, the attached matter detection method of the present invention is an attached matter detection method using a light projecting unit capable of projecting light, wherein the projecting and non-projecting are performed in succession. A light projecting control step for controlling the light projecting means, and an image relating to an object to be imaged that is within a range in which light is projected by the light projecting means at the time of light projection and at the time of non-light projecting. By comparing the imaging step with the brightness at the time of projection, which is the brightness of the image captured at the time of the projection, and the brightness at the time of non-projection, which is the brightness of the image captured at the time of non-projection, And a determination step of determining whether or not the deposit is present on the means.

  According to the adhering matter detection method according to the present invention, the adhering matter is detected based on the image picked up in the imaging step, and therefore, for example, a photodiode or the like for detecting the light projected from the light projecting means is used. There is no need to provide a separate sensor. That is, in the case where an imaging means (for example, a camera used for obtaining an ambient image) used for purposes other than the detection of the attached matter is provided, the attached matter in the light projecting means is used. Can be detected. Therefore, since it is not necessary to use new parts such as a sensor, it is possible to detect the deposit on the light projecting means while reducing or preventing an increase in cost.

  The operation and other advantages of the present invention will become apparent from the best mode for carrying out the invention described below.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, an adhering matter detection apparatus equipped with an infrared projector is mounted on an automobile as an example of the adhering matter detection apparatus of the present invention.

  First, the structure of the deposit | attachment detection apparatus based on this embodiment is demonstrated with reference to FIG. FIG. 1 is a block diagram showing the configuration of the deposit detection apparatus.

  As shown in FIG. 1, the adhering matter detection apparatus 100 includes an infrared projector 110 that is an example of a “projection unit” according to the present invention, and a projector control unit 120 that is an example of a “projection control unit” according to the present invention. An infrared camera 130 which is an example of the “imaging means” according to the present invention, an image input unit 140, an image storage unit 150 at the time of projection, an image storage unit 155 at the time of non-projection, and a luminance information comparison unit 160 The vehicle sensor unit 170, the adhesion determination unit 180, and the time count unit 190 are configured.

  The infrared projector 110 is a projector capable of emitting infrared rays, which is an example of the “projection unit” according to the present invention, and is controlled by the projector control unit 120 which is an example of the “projection control unit” according to the present invention. Thus, it is possible to switch between light projection and non-light projection. For example, the cycle of switching between light projection and non-light projection is performed in a relatively short time of 33 msec. However, since infrared rays are invisible, high-speed blinking does not feel bothersome.

  The infrared camera 130 is a camera capable of receiving infrared rays, which is an example of the “imaging unit” according to the present invention, and takes an image in a range where the infrared rays are projected.

  The image input unit 140 includes, for example, an arithmetic circuit, and distributes the input image into a projected image and a non-projected image.

  The projected image storage unit 150 and the non-projected image storage unit 155 include a memory, for example, and store captured images.

  The luminance information comparison unit 160 includes, for example, an arithmetic circuit, compares input data, and outputs a result.

  The vehicle sensor unit 170 is, for example, a brightness sensor or a speed sensor, which is an example of the “ambient situation detection unit” according to the present invention, and detects a situation around the vehicle.

  The adhesion determination unit 180 includes, for example, an arithmetic circuit, determines the presence / absence of an adhesion from the input information, and outputs the result.

  The time counting unit 190 can measure time by, for example, counting the number of processes. Further, it may be configured to have a clock function and output time information.

  In this embodiment, the image input unit 140, the projected image storage unit 150, the non-projected image storage unit 155, the luminance information comparison unit 160, the adhesion determination unit 180, and the time count unit 190, the “determination” An example of “means” is configured.

  Next, the detailed operation of the deposit detection apparatus according to the present embodiment will be described with reference to FIGS. 2 to 4 in addition to FIG. FIG. 2 is a flowchart showing the operation of the deposit detection apparatus. 3 is a histogram showing the luminance in the image at the time of light projection, and FIG. 4 is a histogram showing the luminance in the image at the time of non-light projection.

  First, three predefined parameters i, j, and Count (where i, j, and Count are natural numbers, respectively) are initialized to “0” (step S1). Here, the parameter i counts the number of images to be captured, the parameter j counts the number of times the luminance is compared, and the parameter Count is a parameter for counting the number of times that a predetermined condition is satisfied.

  Next, the infrared projector 110 is turned on by the projector control means 120, and infrared light is projected in front of the vehicle (step S2). Then, the infrared camera 130 captures an image in the range where the infrared light is projected. At this time, information indicating that the infrared projector 110 is projecting light is output from the projector control unit 120 to the image input unit 140. For this reason, the captured image is determined as an image at the time of projection in the image input unit 140 and stored in the image storage unit 150 at the time of projection (step S3).

  On the other hand, the vehicle sensor unit 170 detects the situation around the vehicle (step S4). The vehicle sensor unit 170 is, for example, a brightness sensor, and can detect the brightness around the vehicle and control the operation of the deposit detection apparatus 100 according to the detected brightness. For example, the set number Mi, threshold Th, set monitor count Mj, and count threshold value N, which will be described later, are changed according to the brightness, or the adhering matter is not determined if the brightness is a predetermined brightness or more. To control. Moreover, the vehicle sensor part 170 is a speed sensor, for example, detects the traveling speed of a vehicle, and controls the operation | movement of the deposit | attachment detection apparatus 100 according to the detected speed. For example, it is possible to change the values of a set number Mi, a threshold value Th, a set monitoring number Mj, and a number threshold number N, which will be described later, according to the speed, or control so as not to determine the adhering matter if the speed is a predetermined speed or higher. Is possible. Thus, by controlling the deposit detection apparatus 100 in accordance with the surrounding situation of the vehicle, it is possible to improve the detection accuracy of the deposit.

  As shown in FIG. 3, the brightness of the image at the time of light projection (that is, the brightness at the time of light projection) can be expressed by, for example, measuring the brightness for each pixel and distributing it. When the luminance for each pixel is known, the average luminance of the entire image can be derived by averaging them (step S5). Note that, instead of or in addition to the average luminance, luminance dispersion, standard deviation, or the like can be used.

  If there is at least one image at the time of projection, it can be compared with an image at the time of non-projection. Here, a case where a predetermined number of images are integrated and compared will be described. The average luminance derived in step S5 is integrated with the average luminance of the image at the time of projection derived in the past (step S6). The average luminance derived from the image at the time of the first projection is omitted since the past average luminance does not exist, and the integration step is omitted. The average brightness of the image at the time is integrated with the average brightness of the image at the time of the first projection, and the average brightness of the image at the time of the third projection is the same as that at the time of the first and second projections. The image is integrated with the average luminance of the image.

Next, the processing at the time of light projection as described above is similarly performed at the time of non-light projection.
In the following, description will be made by appropriately omitting portions overlapping with those at the time of light projection.

  First, the infrared projector 110 is turned off by the projector control means 120, and infrared light is no longer projected in front of the vehicle (step S7). Then, the infrared camera 130 captures an image in a range where the infrared light is projected. At this time, information indicating that the infrared projector 110 is not projecting light is output from the projector control unit 120 to the image input unit 140. For this reason, the captured image is determined as an image at the time of non-light projection in the image input unit 140 and stored in the image storage unit 155 at the time of non-light projection (step S8).

  As shown in FIG. 4, the luminance of an image at the time of non-projection (that is, luminance at the time of non-projection) can be expressed by, for example, measuring the luminance for each pixel and distributing the luminance. Then, as in the case of light projection, the average luminance of the entire image can be derived by averaging the luminance for each pixel (step S9). Further, the derived average luminance is integrated with the average luminance of the non-projected image derived in the past (step S10).

  When the average luminance of the image is integrated during light projection and during non-light projection, '1' is added to each of parameters i and j (step S11). That is, it is incremented.

  Next, the parameter i and the set image number Mi are compared with each other. Here, the set number Mi is a value indicating the number of images to be integrated when the average brightness of the image at the time of projection and the average brightness of the image at the time of non-projection are compared with each other. Yes. However, as described above, the information may be changed by information obtained from the vehicle sensor unit 170 (see step S4). If the parameter i is less than Mi, it means that the number of accumulated images is less than the set number (step S12: NO). For this reason, the process from step S2 is performed again. If the parameter i is greater than or equal to Mi, it means that the number of accumulated images has reached the set number (step S12: YES). Therefore, in this case, the process proceeds to step S13 and subsequent steps.

  When the accumulated images reach the set number Mj, the parameter i is initialized and returns to “0” (step S13). As a result, the set number of images are integrated in the next average luminance comparison.

  Next, the integrated average brightness of the image at the time of light projection and the integrated average brightness of the image at the time of non-light projection are compared with each other, and a difference is derived (step S14). Then, the derived difference is compared with a predetermined threshold Th. The threshold value Th is a value that serves as a reference for determining whether or not there are any deposits on the infrared projector 110, and is experimentally or theoretically determined and set in advance. Or it is calculated | required experimentally or empirically and is preset. However, as described above, the information may be changed by information obtained from the vehicle sensor unit 170 (see step S4). If the derived difference is less than Th, it means that the difference in brightness between light projection and non-light projection is small (that is, the intensity of the infrared projector 110 may be reduced) (step S15: YES). ). In this case, “1” is added to the parameter Count (step S16). If the derived difference is greater than or equal to Th, it means that there is a sufficient difference in brightness between light projection and non-light projection (that is, the intensity of the infrared projector 110 is sufficient) (step S15: NO). In this case, “1” is not added to the parameter Count. That is, step S16 is omitted and the process proceeds to step S17.

  Subsequently, the parameter j and the set monitoring frequency Mj are compared with each other. Here, the set monitor count Mj is a value representing the number of times the difference between the integrated average brightness of the image at the time of projection and the integrated average brightness of the image at the time of non-projection is compared with a threshold value. It is set in advance. However, as described above, the information may be changed by information obtained from the vehicle sensor unit 170 (see step S4). Further, it is possible to calculate Mj in this case by setting the monitoring time t without directly setting the set monitoring number Mj. For example, if the image capture periods at the time of light projection and at the time of non-light projection are the same c, Mj can be obtained from a mathematical formula Mj = t / 2c. When the parameter j is equal to or less than Mj, it means that the number of comparisons between the luminance difference and the threshold is less than the set monitoring number (step S17: NO). For this reason, the process from step S2 is performed again. If the parameter j is larger than Mj, it means that the number of comparisons between the luminance difference and the threshold has reached the set number of monitoring (step S17: YES). Therefore, in this case, the process proceeds to step S18 and subsequent steps.

  When the number of comparisons between the luminance difference and the threshold reaches the set monitoring number Mj, the parameter Count and the number threshold N are compared with each other. The number-of-thresholds N here refers to how many times the condition that the difference between the luminance at the time of projection and the luminance at the time of non-projection is smaller than the threshold Th among the set number of times of monitoring Mj is determined as the presence of an adhering substance. This is a value to be expressed and set in advance. For example, when it is determined that an adhering substance is present when the condition that the difference in luminance is smaller than the threshold value Th is satisfied with a probability higher than 80%, it may be set so as to satisfy the formula N = 0.8 Mj. However, as described above, the information may be changed by information obtained from the vehicle sensor unit 170 (see step S4). If the parameter Count is greater than N, it is determined that there is a deposit on the infrared projector 110 (step S18: YES). In this case, the process proceeds to step S19 and subsequent steps.

  On the other hand, when the parameter Count is N or less, it is determined that no deposit is present on the infrared projector 110 (step S18: NO). For this reason, step S19 is abbreviate | omitted and it progresses to step S20.

  If it is determined that the deposit is present on the infrared projector 110, the deposit detection apparatus 100 outputs a signal (step S19). Thereby, for example, it is possible to notify the driver of the vehicle or the like that the infrared projector 110 is dirty. Note that, as described above, a signal may not be output only when it is determined that the deposit is present, but for example, a value indicating the possibility of the deposit may be output. That is, instead of outputting the presence / absence of deposits as binary values, a continuous value indicating the possibility of deposits is output, or intermittent values or ranks classified by level are output. You may comprise.

  When the above processing is completed, it is determined whether or not to continue detection of the attached matter. When continuing, a process is started again from step S1 (step S20: YES). When not continuing, a process is complete | finished (step S20: NO).

  Next, a specific installation example of the attached matter detection apparatus according to the present embodiment will be described with reference to FIG. Here, FIG. 5 is a side view showing a specific installation example of the deposit detection apparatus. In FIG. 5, for convenience of explanation, among the constituent elements constituting the deposit detection apparatus 100 in FIG. 1, the elements other than the infrared projector 110 and the infrared camera 130 are collectively illustrated as the deposit detection unit 210.

  As shown in FIG. 5, the deposit detection apparatus 100 according to the present embodiment is installed in a vehicle 200.

  The infrared projector 110 is provided, for example, under the headlight, and projects relatively strong infrared light in front of the vehicle 200.

  For example, the infrared camera 130 is provided inside the vehicle 200 and captures an image of an object to be imaged in a range where infrared rays are projected.

  The adhering matter detection unit 210 determines whether an adhering matter is present in the infrared projector 110 using the image captured by the infrared camera 130 and outputs a signal.

  The signal output from the adhering matter detection unit 210 is sent to, for example, the navigation system 220 and notifies the driver of the vehicle of the presence of the adhering matter by giving a warning by a display screen, sound, or the like. Further, here, a washer, a wiper, etc. (not shown) may be provided near the infrared projector 110, and the deposit may be removed automatically or manually.

  The components shown in FIG. 5 can be used by partially changing what is used in a device that supports traveling in a dark environment such as at night by infrared rays. Is possible. That is, by installing the deposit detection apparatus 100 of the present invention, there are few or no parts to be newly added. For example, the adhering matter detection unit 210 can use an existing processing device, memory, or the like by changing software. Therefore, it is possible to detect the deposit on the infrared projector 110 while preventing an increase in cost.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification. And methods are also within the scope of the present invention.

It is a block diagram which shows the structure of a deposit | attachment detection apparatus. It is a flowchart which shows operation | movement of a deposit | attachment detection apparatus. It is a histogram which shows the brightness | luminance in the image at the time of light projection. It is a histogram which shows the brightness | luminance in the image at the time of a non-light-projection. It is a side view which shows the specific example of installation of a deposit | attachment detection apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Adhering matter detection apparatus, 110 ... Infrared light projector, 120 ... Light projector control part, 130 ... Infrared camera, 140 ... Image input part, 150 ... Image storage part at the time of light projection, 155 ... Image storage part at the time of non-light projection, 160 ... Luminance information comparison unit, 170 ... vehicle sensor unit, 180 ... adhesion determination unit, 190 ... time counting unit, 200 ... vehicle, 210 ... deposit detection unit, 220 ... signal output unit

Claims (8)

A light projecting means capable of projecting light;
A light projecting control means for controlling the light projecting means so as to perform light projection and non-light projection one after another;
An imaging unit that captures an image of an object to be imaged within a range in which light is projected by the light projecting unit at each of the light projection time and the non-light projection time;
By comparing the brightness at the time of projection, which is the brightness of the image captured at the time of light projection, with the brightness at the time of non-projection, which is the brightness of the image captured at the time of non-projection, the adhering matter to the light projecting means And a determination means for determining whether or not there is an adhering substance.   The determination unit calculates a difference between the brightness at the time of projection and the brightness at the time of non-projection, and determines that the attached matter is present when the calculated difference is smaller than a predetermined threshold value. The deposit | attachment detection apparatus of Claim 1. The light projection control means controls the light projection means to alternately perform the light projection and the non-light projection,
The imaging means sequentially captures the images,
The determination unit sequentially calculates the difference, and determines that the deposit is present when a state in which the sequentially calculated difference is smaller than the predetermined threshold continues for a predetermined time. Item 3. The deposit detection apparatus according to Item 2. The imaging means captures a plurality of images as the image at the time of light projection and at the time of non-light projection,
The determination means calculates a projection parameter indicating a predetermined statistical value related to the luminance at the time of projection based on the plurality of images captured at the time of projection, and calculates the plurality of images captured at the time of non-projection. Calculating a non-light-projecting parameter indicating a predetermined statistical value related to the non-light-projecting luminance, and comparing the calculated light-projecting parameter and the non-light-projecting parameter with each other, The brightness | luminance and the said brightness | luminance at the time of non-light projection are mutually compared. The adhering matter detection apparatus as described in any one of Claim 1 to 3 characterized by the above-mentioned.   The said light projection means can project light other than visible light as said light, The adhering matter detection apparatus as described in any one of Claim 1 to 4 characterized by the above-mentioned.   The said light projection means contains the light emitting diode, The attached matter detection apparatus as described in any one of Claim 1 to 5 characterized by the above-mentioned. It further comprises an ambient condition detection means for detecting the ambient condition of the attached matter detection device,
The determination unit is configured to determine whether or not an adhering substance is present on the light projecting unit when the surrounding state detected by the surrounding state detection unit is a predetermined state. The deposit | attachment detection apparatus as described in any one of 1 to 6. A deposit detection method using a light projecting means capable of projecting light,
A light projecting control step for controlling the light projecting means so as to perform the light projecting and the non-light projecting one after another,
An imaging step of capturing an image of an object to be imaged within a range in which light is projected by the light projecting unit at each of the light projection time and the non-light projection time;
By comparing the brightness at the time of projection, which is the brightness of the image captured at the time of light projection, with the brightness at the time of non-projection, which is the brightness of the image captured at the time of non-projection, the adhering matter to the light projecting means And a determination step of determining whether or not there is an adhering substance.

Images