JP2013235444A - Vehicle view support apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle view support apparatus capable of enhancing determination accuracy of fog.SOLUTION: A light projector 10 projects near infrared light heading to a predetermined radiation range Al included in a view Af with lighting-on. An image pickup device 20 receives the near infrared light from the radiation area Al during lighting-on of the light projector 10 to image a lighting-on image Ion as a view image I, and receives the near infrared light from the radiation area Al during lighting-off of the light projector 10 to image a lighting-off image Ioff as the view image I. A controller 30 determines the presence/absence of fog in the view Af on the basis of difference of luminance distribution of the radiation area Al on which the lighting-on image Ion and the lighting-off image Ioff imaged by the image pickup device 20 are respectively reflected.

Description

  The present invention relates to a vehicle visibility support apparatus that assists a passenger's vision in a vehicle.

  2. Description of the Related Art Conventionally, there has been known a vehicle vision assistance device that captures a predetermined area that enters a field of view, generates a field image, and determines the presence or absence of fog in the field of view based on the luminance distribution of the field image.

  For example, in the vehicle visibility support device disclosed in Patent Document 1, the luminance distribution of a non-irradiation area outside the irradiation area irradiated with visible light or infrared light among the areas shown in the visual field image is used for determination of fog. doing. As a result, if the illumination light scatters in the fog present in the irradiation area and the brightness in the actual non-irradiation area changes, the luminance distribution in the non-irradiation area reflected in the field-of-view image also changes. It becomes.

JP 2008-33872 A

  Now, in the vehicle visibility support apparatus disclosed in Patent Document 1, it is assumed that a non-irradiation area that is not directly irradiated with light is reflected in the visibility image. Here, when the non-irradiation area is set in the vicinity area of the vehicle as disclosed in Patent Document 1, depending on the illumination angle of the headlight, the position of the hood, the position of the camera that captures the field-of-view image, the angle of view, etc. The non-irradiated area is hardly reflected in the view field image, and there is a possibility that the fog determination accuracy is deteriorated. On the other hand, it is also conceivable to set the non-irradiated area to the sky area. Since it becomes easy to change, this may also deteriorate the fog determination accuracy.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a vehicle visibility support device that enhances fog determination accuracy.

  The present invention is a vehicle visibility support device that assists the occupant's field of view (Af) in the vehicle (2), and irradiates the near-infrared light toward a predetermined irradiation area (Al) entering the field of view by lighting. (10), imaging means (20) for capturing a visual field image (I, Ion, Ioff) by receiving near-infrared light from the irradiation area while the irradiation means is turned on, and the field of view captured by the imaging means Determining means (30, S70, S701 to S715, S3706, S3708, S3713, S3715, S4706b, S4706c, S5700b, S5700c) for determining the presence or absence of fog in the field of view based on the luminance distribution of the irradiation area shown in the image; It is characterized by providing.

  According to the present invention as described above, the luminance distribution of the irradiation region to which the near-infrared light irradiated while the irradiation unit is turned on out of the region reflected in the field-of-view image captured by the imaging unit is the fog distribution in the irradiation region. It changes depending on the presence or absence. Therefore, it is possible to accurately determine the presence or absence of fog based on the luminance distribution of such an irradiation area. Moreover, since the irradiation region is a region that irradiates near-infrared light without a dazzling action that makes a person feel dazzling, it can be freely set within a range that can improve the determination accuracy of fog.

  Further, as a further feature of the present invention, the field-of-view image (I) captured by the imaging unit while the irradiation unit is turned on is defined as a lighting image (Ion), and is captured by the imaging unit while the irradiation unit is turned off. When the view field image (I) is defined as a light-off image (Ioff), the determination unit determines the presence or absence of fog in the field of view based on the difference in the luminance distribution of the irradiation area shown in each of the light-up image and the light-off image.

  According to this feature, between the irradiation region reflected in the lighting image captured as the field-of-view image while the irradiation unit is turned on and the irradiation region reflected in the extinguished image captured as the field-of-view image while the irradiation unit is turned off, A difference in luminance distribution due to only near-infrared light actually irradiated during lighting can be generated. In other words, the difference in luminance distribution of the irradiated area shown in each of the lit image and the extinguished image can be obtained by removing the influence of near-infrared light in the external light. Accuracy can be increased.

  Further, as a further feature of the present invention, the fog lamp of the vehicle is turned on in response to the determination of the presence of fog by the determination means, while the determination means determines that the fog is not determined. Lamp control means (30, S90, S100, S110) for turning off the fog lamp is further provided.

  According to this feature, the fog light of the vehicle automatically turns on and off as the determination of the presence or absence of fog is accurately made, so if the fog lamp forgets to turn off in a driving environment without fog, the following vehicle or oncoming vehicle A situation in which a dazzling action is given to the passengers can be avoided.

It is a mimetic diagram showing the state where the vehicle visibility support device by a first embodiment was applied to vehicles. It is a block diagram which shows the structure of the vehicle visibility support apparatus by 1st embodiment. It is a schematic diagram for demonstrating the luminance analysis of the visual field image by 1st embodiment. It is a characteristic view for demonstrating the fog determination method by 1st embodiment. It is a schematic diagram for demonstrating the fog determination method by 1st embodiment. It is a flowchart which shows the vehicle vision assistance flow by 1st embodiment. It is a schematic diagram for demonstrating the detail of S10 of FIG. It is a flowchart which shows the detail of S40 of FIG. It is a flowchart which shows the detail of S60 of FIG. It is a flowchart which shows the detail of S70 of FIG. It is a schematic diagram for demonstrating the brightness | luminance analysis of the visual field image by 2nd embodiment. It is a schematic diagram for demonstrating the detail of S10 of 3rd embodiment. It is a flowchart which shows the detail of S70 of 3rd embodiment. It is a block diagram which shows the structure of the vehicle visibility support apparatus by 4th embodiment. It is a flowchart which shows the detail of S70 of 4th embodiment. It is a flowchart which shows the detail of S70 of 5th embodiment. It is a flowchart which shows the modification 1. It is a flowchart which shows the modification 2. 10 is a flowchart showing a third modification. 10 is a flowchart showing Modification Example 4. 10 is a flowchart showing a fifth modification. 10 is a flowchart showing Modification Example 6. 10 is a flowchart showing Modification Example 7. 10 is a flowchart showing Modification Example 8. 10 is a flowchart showing Modification Example 8. FIG. 10 is a schematic diagram showing Modification Example 9. 10 is a flowchart showing Modification Example 9. 10 is a flowchart showing Modification Example 10. 10 is a flowchart showing Modification Example 11.

  Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In addition, the overlapping description may be abbreviate | omitted by attaching | subjecting the same code | symbol to the corresponding component in each embodiment. When only a part of the configuration is described in each embodiment, the configuration of the other embodiment described above can be applied to the other part of the configuration. In addition, not only combinations of configurations explicitly described in the description of each embodiment, but also the configurations of a plurality of embodiments can be partially combined even if they are not explicitly specified unless there is a problem with the combination. .

(First embodiment)
As shown in FIG. 1, a vehicle visibility support device 1 according to a first embodiment of the present invention is mounted on a vehicle 2 and assists an occupant's forward vision Af (hereinafter simply referred to as “vision Af”). As shown in FIG. 2, the vehicle visibility support device 1 includes a projector 10, an image sensor 20, a control device 30, and a display device 40.

  The projector 10 is composed mainly of one or a plurality of LEDs or the like, for example, and has a near-infrared wavelength in a predetermined wavelength range of a general near-infrared wavelength range (about 700 nm to about 1100 nm). Emits light. The projector 10 is installed in the front part of the vehicle 2, for example, a front bumper, etc., and irradiates near infrared light toward the predetermined irradiation area | region Al which enters into the visual field Af like FIG. That is, in the present embodiment, the projector 10 corresponds to “irradiation means”. Here, the irradiation angle θ of the projector 10 is set to, for example, 15 °, and the irradiation distance X of the projector 10 is set to, for example, 100 m or the like that is difficult for the passenger of the vehicle 2 to see at night when the field of view Af is dark. Is done.

  The imaging element 20 shown in FIG. 2 is a so-called night vision camera mainly composed of, for example, a CMOS sensor having sensitivity to near infrared light and visible light. The imaging element 20 is installed in the vehicle 2, for example, on the inside or outside of the front windshield, so that the imaging range substantially matches the irradiation area Al of the projector 10. The image sensor 20 receives near-infrared light and visible light reaching from the irradiation area Al while the projector 10 is turned on or off, and outputs an image signal corresponding to the amount of received light. Therefore, the image signal output from the image pickup device 20 represents the luminance information of the visual field image I (see FIG. 3 described in detail later) in which the irradiation area Al is shown in the visual field Af. In other words, the imaging element 20 corresponds to “imaging means” that captures the field-of-view image I.

  The control device 30 is configured by combining, for example, an image processing chip and a microcomputer. In the vehicle 2, the control device 30 is connected to the light switch 3, the headlight 4a, the taillight 4b, the fog lamp switch 5, the front fog lamp 6a, the rear fog lamp 6b, the night view switch 7 and the vehicle speed sensor 8 via an in-vehicle LAN 9 such as CAN. Connected.

  Here, the operation position is set to the light switch 3 so that the occupant can manually switch on and off the headlight 4a and the taillight 4b. The fog lamp switch 5 includes an operation position for automatically switching on / off of the fog lamps 6a and 6b in addition to an operation position for the passenger to manually switch on / off the front fog lamp 6a and the rear fog lamp 6b (hereinafter referred to as “automatic”). "Position") is set. The front fog lamp 6a radiates white or yellow visible light in front of the vehicle 2 at an angle wider than the headlight 4a in the horizontal direction and narrower in the vertical direction. The rear fog lamp 6b emits light in red that is brighter than the taillight 4b. An operation position is set on the night view switch 7 so that the occupant can manually switch the night view display that supports the field of view Af at night or the like. The vehicle speed sensor 8 detects the traveling speed of the vehicle 2 and outputs a detection signal thereof.

  The control device 30 is also connected to the projector 10, the image sensor 20, and the display device 40 via the in-vehicle LAN 9. The control device 30 controls the operations of the projector 10 and the image sensor 20 according to the operation positions of the switches 3, 5, 7 and the detection signal of the vehicle speed sensor 8, while the image sensor 20 is turned on or off. A visual field image I as shown in FIG. 3 is generated by processing the image signal output from.

  The control device 30 further determines the presence or absence of fog in the field of view Af based on the luminance distribution of the field of view image I thus shot. Here, especially the control apparatus 30 of this embodiment permits fog determination, when the light switch 3 is switched to the extinguishing position of the lights 4a and 4b. That is, switching to the extinguishing position by the light switch 3 corresponds to “bright condition with bright field of view”. Further, the control device 30 of the present embodiment adds the traveling speed of the vehicle 2 to the fog determination permission condition that the traveling speed of the vehicle 2 is equal to or higher than a predetermined set speed Vthl (see FIG. 8 described in detail later). Is less than the set speed Vthl, fog determination is prohibited. Further, the control device 30 according to the present embodiment automatically switches on the fog lamps 6a and 6b according to the determination of the presence of fog while adding the fog lamp switch 5 to the automatic position to the fog determination permission condition. The fog lamps 6a and 6b are automatically turned off according to the non-determination. As described above, in the present embodiment, the control device 30 functions as a “determination unit” and a “lamp control unit”.

  The display device 40 shown in FIG. 2 is mainly composed of a liquid crystal display, for example. The display device 40 can be visually recognized by a passenger by being installed in the front of the vehicle 2 in the room. The display device 40 displays the generated image of the control device 30 connected to the display device 40, particularly the view image I permitted to be displayed by the night view switch 7 in this embodiment. That is, the display permission by the night view switch 7 corresponds to the “dark dark condition of view”.

(Fog judgment processing)
Next, features of the fog determination process performed by the control device 30 will be described in detail.

  In the fog determination process, as shown in FIG. 4, the control device 30 processes the view image I captured while the projector 10 is turned on as the lighting image Ion, while the view image I captured while the projector 10 is turned off. , Processed as the extinguishing image Ioff. At this time, within a predetermined lighting period Ton of the projector 10, the lighting images Ion for a plurality of frames are continuously set with the exposure time Tl by the imaging device 20 and the imaging cycle Ti by the imaging device 20 and the control device 30 being substantially constant. To get to. Further, within the light extinction period Toff of the projector 10 that is substantially the same as the lighting period Ton, the exposure time Tl and the imaging period Ti are substantially constant and substantially the same length as in the lighting period Ton. Images Ioff are acquired continuously. Here, in particular, in the present embodiment, the number N of frames for photographing each of the images Ion and Ioff is set to two set speeds Vthm and Vthh (see FIG. 8 described in detail later) as the traveling speed of the vehicle 2 increases. As the time exceeds, the time decreases as shown in FIG. 4 (a) to (b), and the time periods Ton and Toff also decrease according to the decrease.

  As shown in FIG. 3, the control device 30 sets an analysis region Aa for analyzing the luminance distribution for each of the lighting image Ion and the lighting-off image Ioff acquired in a plurality of frames in this way. Here, in particular, the analysis area Aa of the present embodiment is set to a partial area Aac including the central portion in the horizontal direction among the irradiation areas Al shown in the images Ion and Ioff.

  The control device 30 further calculates the luminance distribution of the analysis region Aa (partial region Aac) set in the lighting image Ion of each frame and the luminance distribution of the analysis region Aa (partial region Aac) set in the extinguishing image Ioff of each frame. Analyze and extract the luminance distribution difference between the former and the latter. At this time, as shown in FIG. 5, the luminance values of all the pixels in the analysis area Aa are averaged for each lighting image Ion of the number of photographing frames N, and the average value Lon for each lighting image Ion is further averaged for all the frames. Thus, the luminance average value ΣLon / N representing the former luminance distribution is calculated. At the same time, the luminance values of all the pixels in the analysis area Aa are averaged for each non-lighted image Ioff of the number of captured frames N, and the average value Loff for each non-lighted image Ioff is further averaged for all the frames, thereby obtaining the latter luminance. A luminance average value ΣLoff / N representing the distribution is calculated. In particular, in this embodiment, the difference between the luminance average value ΣLon / N of the lit image Ion and the luminance average value ΣLoff / N of the unlit image Ioff is extracted as the luminance distribution difference between the images Ion and Ioff. As described above, in the present embodiment, the control device 30 functions as “calculation means”.

  Furthermore, the control device 30 determines the presence or absence of fog in the field of view Af based on the luminance distribution difference between the extracted images Ion and Ioff. At this time, if the difference in luminance distribution between the images Ion and Ioff is greater than or equal to the determination criterion Δth (see FIG. 10 described in detail later), the presence of fog is determined, while the difference in luminance distribution between the images Ion and Ioff is less than the determination criterion Δth. When it becomes, it makes no judgment of fog. Here, in particular, in the present embodiment, when one of the determination and non-determination is consecutively made, by confirming the one determination, after the determination, the other of the determination and non-determination is continuously performed. The one determination is maintained until it is made. In addition, regarding the number of times of confirmation Cth (see FIG. 10 to be described later in detail) for confirming that the determination of the same content has been continued until the determination, the determination criterion for the determination of the one is used after the determination of one determination. The number of times used as the determination criterion for the other determination is set larger than the number of times. Furthermore, the determination criterion Δth at each determination that is repeated until the determination is set to a constant value in the present embodiment.

(Vehicle visibility support flow)
Next, the vehicle visibility support flow executed by the control device 30 including the fog determination process as described above will be described in detail with reference to FIGS. The vehicle visibility support flow starts when the engine switch of the vehicle 2 is turned on and ends when the engine switch is turned off.

  As shown in FIG. 6, in S10 of the vehicle visibility support flow, various parameters and flags are initialized. At this time, as shown in FIG. 7, specifically, together with the above-described number of frames N, the continuous presence determination number Cies indicating the number of consecutive determinations of fog and the continuous number indicating the number of consecutive determinations of fog. The non-determination count Cno is initialized to “0”. Also, the above-mentioned number of confirmations Cth is initialized to “4”. Furthermore, a determination feasibility flag Frw indicating whether or not the fog determination can be executed, a confirmation flag Fc indicating whether or not the same determination is being continuously performed until confirmation, and a determination result flag Fyn indicating the result of the confirmed fog determination Are initialized to “OFF”.

  In S20 of FIG. 6 following such S10, it is determined whether or not the light switch 3 has been switched to the extinguishing position of the lights 4a and 4b. As a result, if a negative determination is made, the process returns to S10, whereas if an affirmative determination is made, the process proceeds to S30.

  In S30, it is determined whether or not the fog lamp switch 5 has been switched to the auto position. As a result, if a negative determination is made, the process returns to S10, whereas if an affirmative determination is made, the process proceeds to S40.

  In S40, a vehicle speed determination subroutine is executed. As shown in FIG. 8, in S401 of the vehicle speed determination subroutine, it is determined whether or not the traveling speed of the vehicle 2 is less than the minimum set speed Vthl (for example, 20 km / h representing slow driving). As a result, when an affirmative determination is made, the process proceeds to S402, and the determination enable / disable flag Frw is updated to “OFF” indicating prohibition of execution of the fog determination. On the other hand, if a negative determination is made, the process proceeds to S403.

  In S403, it is determined whether or not the traveling speed of the vehicle 2 is not less than the minimum set speed Vthl and less than the intermediate set speed Vthm (for example, 40 km / h). As a result, when an affirmative determination is made, the process proceeds to S404, and the number of captured frames N is updated to the maximum “16”. On the other hand, if a negative determination is made, the process proceeds to S405.

  In S405, it is determined whether or not the traveling speed of the vehicle 2 is not less than the intermediate set speed Vthm and less than the maximum set speed Vthh (for example, 60 km / h). As a result, when an affirmative determination is made, the process proceeds to S406, and the number of captured frames N is updated to “8”, which is smaller than in the case of S404. On the other hand, if a negative determination is made, the process proceeds to S407.

  In S407 when the traveling speed of the vehicle 2 is equal to or higher than the maximum set speed Vthh, the number N of captured frames is updated to “4”, which is further reduced than in the case of S406.

  Then, after S404, S406, and S407 for updating the number N of captured frames, the process proceeds to S408, and the determination enable / disable flag Frw is updated to “ON” indicating permission to execute the fog determination. Thus, the vehicle speed determination subroutine is completed.

  In S50 of FIG. 6 following such a vehicle speed determination subroutine, it is determined whether or not the determination availability flag Frw is “ON”. As a result, if a negative determination is made, the process returns to S10, whereas if an affirmative determination is made, the process proceeds to S60.

  In S60, a luminance analysis subroutine is executed. As shown in FIG. 9, in the luminance analysis subroutine S601, the frame counter Cf is set to “1”, and in the next S602, the projector 10 is turned on to irradiate the irradiation area Al with near infrared light. In subsequent S603, the lighting image Ion is photographed by the image sensor 20, and the luminance analysis is performed on the analysis region Aa in the irradiation region Al reflected in the photographed lighting image Ion, thereby obtaining the average luminance value Lon in the region Aa. calculate. Thereafter, in S604, “1” is added to the frame counter Cf, and in S605, it is determined whether or not the frame counter Cf has reached the number N of frames to be captured. As a result, S603 to S605 are repeated while a negative determination is made, and when an affirmative determination is made, the process proceeds to S606.

  In S606, the irradiation of the near-infrared light to the irradiation area Al is stopped by turning off the projector 10. In the subsequent S607, the extinguishing image Ioff is photographed by the image sensor 20, and the luminance analysis of the analysis area Aa in the irradiation area Al reflected in the photographed extinguishing image Ioff is performed, whereby the average value Loff of the luminance in the area Aa is obtained. calculate. Thereafter, in S608, “1” is added to the frame counter Cf, and in S609, it is determined whether or not the frame counter Cf has reached a double value of the number N of captured frames (that is, 2N). As a result, S607 to S609 are repeated while a negative determination is made, and when an affirmative determination is made, the process proceeds to S610.

  In S610, the luminance distribution difference between the captured images Ion and Ioff is extracted. Specifically, the average luminance value ΣLon / N related to the lighting images Ion of all frames is calculated from the average value Lon of the luminance within the area Aa calculated for each lighting image Ion taken in S603 each time. At the same time, the average luminance value ΣLoff / N relating to the extinguished image Ioff of all frames is calculated from the average value Loff of the luminance in the area Aa calculated for each extinguished image Ioff in S607. Then, the absolute value of the difference between the luminance average values ΣLon / N and ΣLoff / N calculated in this way is extracted as the luminance distribution difference between the images Ion and Ioff. Thus, the luminance analysis subroutine ends.

  In S70 of FIG. 6 following such a luminance analysis subroutine, a fog determination subroutine is executed. As shown in FIG. 10, in S701 of the fog determination subroutine, it is determined whether or not the luminance distribution difference extracted in S610 of the immediately preceding luminance analysis subroutine is greater than or equal to the determination criterion Δth. As a result, if a positive determination is made, the process proceeds to S702.

  In S702, it is determined whether or not the determination result flag Fyn is “ON”. As a result, when the affirmative determination is made, the fog determination subroutine is terminated, whereas when the negative determination is made, the process proceeds to S703, and “1” is added to the continuous determination number Cies and the continuous determination is continued. The non-determination count Cno is reset to “0”. Further, the process proceeds to S704, where it is determined whether or not the continuous presence determination number Cyes has reached the confirmation number Cth.

  If a negative determination is made in S704, it is determined that the determination of fog is unconfirmed, the process proceeds to S705, and the checking flag Fc is updated to “ON”. Further, the process proceeds to S706 where the number of confirmations Cth is updated to the normal “4”, and then the fog determination subroutine is terminated.

  On the other hand, if an affirmative determination is made in S704, it is determined that the determination of fog is confirmed, the process proceeds to S707, the determination result flag Fyn is updated to “ON”, and the confirmation flag Fc is updated to “OFF”. To do. Further, the process proceeds to S708, the number of confirmations Cth is updated to “8”, which is larger than S706 before the determination is confirmed, and the number of consecutive determinations Cies is reset to “0”, and then the fog determination subroutine is terminated.

  Up to this point, the case where an affirmative determination is made in S701 has been described. However, if a negative determination is made in S701, the process proceeds to S709 to determine whether or not the determination result flag Fyn is “OFF”. judge. As a result, when the affirmative determination is made, the fog determination subroutine is terminated, whereas when the negative determination is made, the process proceeds to S710, and “1” is added to the continuous non-determination number Cno and Reset the number of valid times Cies to “0”. Further, the process proceeds to S711, where it is determined whether or not the consecutive non-determination number Cno has reached the confirmation number Cth.

  If a negative determination is made in S711, it is determined that no fog determination has been made yet, the process proceeds to S712, and the checking flag Fc is updated to “ON”. Further, the process proceeds to S713, where the number of confirmations Cth is updated to the normal “4”, and then the fog determination subroutine is terminated.

  On the other hand, if an affirmative determination is made in S711, it is determined that no determination of fog has been established, the process proceeds to S714, the determination result flag Fyn is updated to “OFF”, and the confirmation flag Fc is updated to “OFF”. To do. Further, the process proceeds to S715, the number of confirmations Cth is updated to “8”, which is larger than S713 before the determination is confirmed, and the continuous non-determination number Cno is reset to “0”, and then the fog determination subroutine is terminated.

  In S80 of FIG. 6 following such a fog determination subroutine, it is confirmed whether or not the checking flag Fc is “OFF”. As a result, if a negative determination is made, the process returns to S20, whereas if an affirmative determination is made, the process proceeds to S90.

  In S90, it is determined whether or not the determination result flag Fyn is “ON”. As a result, when an affirmative determination is made, it is determined that the determination of the presence of fog has been confirmed, and the process proceeds to S100 to automatically turn on the fog lamps 6a and 6b. On the other hand, if a negative determination is made, it is determined that no determination of fog has been established, the process proceeds to S110, and the fog lamps 6a and 6b are automatically turned off. And after automatic lighting or automatic extinguishing of each fog lamp 6a, 6b is implement | achieved by the above, it will return to S20.

(Function and effect)
The effects of the first embodiment described above will be described below.

  According to the first embodiment, the luminance distribution of the irradiation area Al to which the near-infrared light irradiated during lighting of the projector 10 among the areas shown in the lighting image Ion photographed as the view image I is in the area Al. It changes depending on the presence or absence of fog. Therefore, it is possible to accurately determine the presence or absence of fog based on the luminance distribution of the irradiation area Al. Moreover, since the irradiation area Al is an area that irradiates near-infrared light without a dazzling effect that makes a person feel dazzling, it can be freely set within a range that can improve the determination accuracy of fog. .

  Further, according to the first embodiment, the view field image I captured while the projector 10 is turned on is processed as the lit image Ion, and the view field image I captured while the projector 10 is turned off is processed as the unlit image Ioff. As a result, a difference in luminance distribution due to only near-infrared light actually irradiated during lighting of the projector 10 is caused between the irradiation area Al reflected in the lit image Ion and the irradiation area Al reflected in the unlit image Ioff. obtain. That is, the difference in luminance distribution of the irradiation area Al shown in each of the lit image Ion and the extinguished image Ioff can be removed from the influence of near-infrared light in the outside light. Fog determination accuracy can be increased.

  Here, in the first embodiment, since the fog determination is performed based on the average luminance values ΣLon / N and ΣLoff / N of the irradiation area Al that are displayed in the images Ion and Ioff of a plurality of frames taken continuously, the luminance Misjudgment of fog due to accidental fluctuation of distribution can be suppressed. At the same time, in the first embodiment, the number N of frames taken for each of the images Ion and Ioff for which the average luminance values ΣLon / N and ΣLoff / N are calculated is the luminance distribution in the irradiation area Al reflected in each of the images Ion and Ioff. Decreases as the speed of the vehicle 2 increases. According to this, the average brightness values ΣLon / N and ΣLoff / N are calculated in the range of the number of photographing frames N that can suppress variations in the brightness distribution, and fog determination based on the average values ΣLon / N and ΣLoff / N Accuracy can be increased. Further, in the first embodiment, for one fog determination, the projector 10 is not only turned on for a certain period Ton to shoot a lighting image Ion, but the projector 10 is turned off for the same period Ton and turned off. Since Ioff is photographed, the power consumption by the projector 10 can be suppressed.

  Furthermore, according to the first embodiment, the fog lamps 6a and 6b of the vehicle 2 are automatically turned on / off in accordance with the accurate determination of the presence or absence of fog as described above. Therefore, it is possible to avoid a situation in which a dazzling action is given to the occupant or the like of the succeeding vehicle or the oncoming vehicle due to forgetting to turn off the fog lamps 6a and 6b in a fogless traveling environment.

  In addition, according to the first embodiment, one of the determinations determined by the continuous determination between the presence / absence of fog is not only highly accurate, but the other determination is continuously made. Up to this point, the one determination is maintained, and it is difficult to make an erroneous determination due to an accidental luminance distribution change. Therefore, according to the fog determination realized with high accuracy in this way, the effect of avoiding the dazzling action by the fog lamps 6a and 6b can be surely exhibited. In addition, after the determination of one determination is confirmed, the number of times of confirmation Cth for confirming that the other determination is continuous increases, so that the determination of the one is easily maintained. Therefore, it is possible to prevent the fog lamps 6a and 6b from being repeatedly turned on and off due to frequent changes in the fog determination result.

  In addition, in the first embodiment, fog determination is permitted according to the light switch 3 being switched to the extinguishing position of the lights 4a and 4b in the daytime when the bright condition of the visibility Af is satisfied, and the determination result Accordingly, the fog lamps 6a and 6b are automatically turned on and off. According to this, even if fog occurs in a light driving environment where the lights 4a and 4b are turned off, forgetting to turn on the fog lamps 6a and 6b can be avoided, and the field of view of passengers and the like in the own vehicle 2 or the following vehicle can be avoided. Can help. At the same time, in the first embodiment, fog determination is prohibited when the traveling speed of the vehicle 2 is less than the predetermined set speed Vthl and it becomes easy for a forward vehicle or the like to enter the irradiation area Al. Therefore, it is possible to suppress erroneous determination caused by a preceding vehicle or the like that has entered the irradiation area Al.

  In addition, the imaging device 20 of the first embodiment is not only a night vision camera that captures the display image I of the display device 40 at night or the like when the dark dark condition of the field of view Af is satisfied, but also the lit image Ion and the unlit image. It is also used for fog determination based on Ioff. According to this, it becomes possible to simplify the vehicle visibility support apparatus 1 by integrating functions.

  In addition, the partial area Aac including the central portion in the horizontal direction in the irradiation area Al of the first embodiment has high near-infrared light irradiation intensity. The luminance of the partial area Aac in the irradiation area Al reflected in Ioff also increases. Therefore, based on the luminance distribution of the region Aac, the partial region Aac including the central portion in the horizontal direction in the irradiation region Al shown in the lit image Ion and the unlit image Ioff is used. Is possible.

(Second embodiment)
The second embodiment of the present invention shown in FIG. 11 is a modification of the first embodiment. In the second embodiment, the analysis area Aa for analyzing the luminance distribution with respect to the lit image Ion and the unlit image Ioff as the view image I is located on the opposite lane side in the horizontal direction in the irradiation area Al reflected in the images Ion and Ioff. The biased partial area Aad is set.

  According to such a second embodiment, it is difficult for a forward vehicle or an oncoming vehicle or the like to enter the partial area Aad that is biased toward the opposite lane in the horizontal direction in the irradiation area Al. Therefore, based on the luminance distribution of the region Aad, the partial region Aad biased toward the opposite lane side of the irradiation region Al reflected in the lighting image Ion and the extinguishing image Ioff as the view image I is used as the analysis region Aa. It is possible to suppress erroneous determination caused by a preceding vehicle or an oncoming vehicle that has entered the road.

(Third embodiment)
The third embodiment of the present invention shown in FIGS. 12 and 13 is a modification of the first embodiment. In S10 executed by the control device 30 of the third embodiment, as shown in FIG. 12, the determination criterion Δth is initialized to the normal value Δth0 together with the initialization described in the first embodiment. Accordingly, in the fog determination subroutine of S70 executed by the control device 30 of the third embodiment, as shown in FIG. 13, the determination criterion Δth is updated to strict values Δthsy and Δthsn when a predetermined condition is satisfied.

  More specifically, in S3708, which is shifted to S707 after the determination of the presence of fog is confirmed, the update and reset described in the first embodiment are executed, and the stricter value is smaller than the normal value Δth0. The determination criterion Δth is updated to the value Δthsy. As a result, in the fog determination subroutine after the fog determination subroutine is temporarily terminated through S3708 and then no fog determination is determined, the determination criterion Δth in S701 becomes stricter against the no determination. Note that in S3706, which is shifted to S705 after the determination of the presence of fog is unconfirmed, the update described in the first embodiment is executed, and the determination criterion Δth is returned to the normal value Δth0.

  In addition, in S3715, which is shifted to S714 after the determination that no fog is determined, the update and reset described in the first embodiment are executed, and the strict value Δthsn larger than the normal value Δth0 is set. The determination criterion Δth is updated. As a result, in the fog determination subroutine after the fog determination subroutine is temporarily ended through S3715 and the determination of the presence of fog is confirmed, the determination criterion Δth in S701 becomes stricter with respect to the determination. Note that, in S3713, which is shifted to S712 after the determination that the fog is not determined yet, the update described in the first embodiment is executed, and the determination criterion Δth is returned to the normal value Δth0.

  In such a third embodiment, the determination criterion Δth becomes stricter with respect to the other determination after the determination of one of the fogged determination and the non-determination is confirmed, so that the one determination is easily maintained. Therefore, like the first embodiment, coupled with the effect of increasing the number of confirmations Cth after the determination is confirmed, the result of the fog determination frequently changes and the fog lamps 6a and 6b are repeatedly turned on and off. It can be suppressed.

(Fourth embodiment)
The fourth embodiment of the present invention shown in FIGS. 14 and 15 is a modification of the first embodiment. As shown in FIG. 14, the control device 30 of the fourth embodiment is connected to the navigation device 50 via the in-vehicle LAN 9. The navigation device 50 acquires position information of the vehicle 2 and the like.

  As shown in FIG. 15, in the fog determination subroutine of S70 executed by the control device 30 of the fourth embodiment, in S4706a that is shifted to S705 because the determination of the presence of fog is unconfirmed, the current travel environment Predict the occurrence of fog in At this time, in the present embodiment, based on the position information output from the navigation device 50, it is determined whether or not the vehicle 2 is traveling in an environment where the occurrence of fog is predicted, for example, in a mountainous area or near a tunnel exit. ,judge. As a result, if a negative determination is made, the process proceeds to S4706b and the number of confirmations Cth is updated to the normal “4”, whereas if an affirmative determination is made, the process proceeds to S4706c and from S4706b. The number of confirmation times Cth is updated to “2” which is also less. It should be noted that the fog determination subroutine is terminated after the confirmation count Cth is updated by either S4706b or S4706c.

  According to such a fourth embodiment, the fog determination determined by being continuous is not only highly accurate, but also when the occurrence of fog is predicted, the number of consecutive confirmations Cth. Can be quickly reduced. According to this, when the vehicle 2 enters the traveling environment in which fog is generated, the fog lamps 6a and 6b can be quickly turned on to support the field of view of the passenger or the like in the own vehicle 2 or the following vehicle. As described above, in the fourth embodiment, the control device 30 functions as “prediction means”.

(Fifth embodiment)
The fifth embodiment of the present invention shown in FIG. 16 is a modification of the third embodiment. In S10 executed by the control device 30 of the fifth embodiment, the same processing content as that of S10 in the third embodiment is performed (see FIG. 12). Accordingly, in the fog determination subroutine of S70 executed by the control device 30 of the fifth embodiment, as shown in FIG. 16, the determination criterion Δth is updated to the relaxation value Δthd when a predetermined condition is satisfied.

  Specifically, prior to determination of the luminance distribution difference in S701, in S5700a, the same processing content as that in S4706a described in the fourth embodiment is performed. As a result, when an affirmative determination is made, the process proceeds to S5700b, where the determination criterion Δth is updated to a relaxation value Δthd smaller than the normal value Δth0. As a result, in S701 following S5700b, the determination criterion Δth becomes loose for the determination. In S5700c, which is shifted when a negative determination is made in S5700a, the determination criterion Δth is returned to the normal value Δth0.

  According to the fifth embodiment as described above, when the occurrence of fog is predicted, the determination criterion Δth is relaxed with respect to the determination of the presence of fog, so that the determination is easily made. According to this, the fog lamps 6a and 6b can be reliably turned on in a traveling environment in which fog is likely to be generated, and the field of view of the passenger or the like in the own vehicle 2 or the following vehicle can be supported. As described above, also in the fifth embodiment, the control device 30 functions as “prediction means”.

(Other embodiments)
Although a plurality of embodiments of the present invention have been described above, the present invention is not construed as being limited to these embodiments, and various embodiments and combinations can be made without departing from the scope of the present invention. Can be applied.

  Specifically, in the first to fifth embodiments, the field of view Af is determined by determining whether or not the illuminance detected by the illuminance sensor of the vehicle 2 in S20 is equal to or greater than a threshold as in Modification 1 shown in FIG. It may be determined whether or not the bright light condition is satisfied. In the first to fifth embodiments, S20 may be omitted as in Modification 2 shown in FIG. According to the second modification, the fog determination can be accurately performed regardless of the brightness of the field of view Af.

  In the first to fifth embodiments, as in Modification 3 shown in FIG. 19, it is determined whether or not the fog lamp switch 5 is switched to the manual lighting position in S30, and the lighting of the fog lamps 6a and 6b is continued in S100. You may do it. According to the third modification, even when the fog lamps 6a and 6b are manually turned on, a dazzling action is given to the occupant or the like of the following vehicle or the oncoming vehicle by forgetting to turn off the fog lamps 6a and 6b in a driving environment without fog. The situation can be avoided. In the first to fifth embodiments, as in Modification 4 shown in FIG. 20, S30 may be omitted, and the determination result of S90 may be notified to the occupant by displaying the display device 40 in S100 and S110.

  In the first to fifth embodiments, as in Modification 5 shown in FIG. 21, it is determined in S40 whether or not an erroneous determination target object such as a forward vehicle has entered the irradiation area Al in S409 prior to S401. If the result is affirmative, S401 and subsequent steps may be executed. In S402 of the fifth modification, accurate fog determination can be realized even when the vehicle 2 is slowing down by updating the number of frames N to “32”, for example, larger than “16”. At the same time, in the fifth modification, when a negative determination is made in S409, the determination possibility flag Frw is set to “OFF” in S410, so that the erroneous determination caused by the preceding vehicle or the like that has entered the irradiation area Al is ensured. Can be suppressed.

  In the first to fifth embodiments, as in Modification 6 shown in FIG. 22, the number N of captured frames may be updated to, for example, “32” larger than “16” in S402 of S40. In this modified example 6, S50 (not shown) becomes unnecessary together with S408 of S40. Further, in the first to fifth embodiments, as in Modification 7 shown in FIG. 23, S602 and S603 for photographing the lit image Ion and S606 and S607 for photographing the unlit image Ioff are interchanged, S60 may be performed. Furthermore, in the first to fifth embodiments, as in Modification 8 shown in FIG. 24, S40 and S50 may be omitted, and a fixed number of frames N may be adopted regardless of the traveling speed of the vehicle 2. In the modified example 8, the number N of frames to be captured is further fixed to “1”. As shown in FIG. 25, in S60, S601, S604, S605, S608, and S609 are omitted, and one frame is obtained in S603 and S606. In S601, the luminance distribution difference between the lit image Ion and the unlit image Ioff captured one by one may be extracted.

  In the first to fifth embodiments, as in Modification 9 shown in FIG. 26, the variance values of all the pixels in the analysis area Aa are averaged for each image Ion or Ioff of the number N of frames to be captured, and the image of each frame The average luminance value ΣDon / N or ΣDoff / N representing the luminance distribution may be calculated by further averaging the variance values Don and Doff for each Ion or Ioff with respect to all frames. In S60 of the modified example 9, as shown in FIG. 27, the variance value Don of the luminance in the analysis area Aa reflected in the lit image Ion is calculated in S603, and in the analysis area Aa reflected in the extinguished image Ioff in S607. In S610, the absolute value of the difference between the luminance average values ΣDon / N and ΣDoff / N is extracted as the luminance distribution difference between the images Ion and Ioff. In the modified example 9, instead of the dispersion values Don and Doff, for example, a control determination parameter for the automatic exposure function of the image sensor 20 may be employed.

  In the first to fifth embodiments, as in Modification 10 shown in FIG. 28 (FIG. 28 is Modification 10 related to the first embodiment), the number of confirmations Cth is determined in S708, S3708, S715, and S3715 of S70 before the determination is confirmed. The same “4” may be set. In the first to fifth embodiments, as in Modification 11 shown in FIG. 29 (FIG. 29 is Modification 11 related to the first embodiment), S703 to S706, S4706a to c, S708, S3708, and S710 of S70. ~ S713, S715, S3715 may be omitted, and the presence or absence of fog may be determined by a single determination by only updating the determination result flag Fyn in S707 and S714. Furthermore, as a modified example 12 of the fourth and fifth embodiments, the determination criterion Δth may be set strictly after the determination is confirmed according to the third embodiment.

  As a modified example 13 of the first to fifth embodiments, not only the visual field image I is displayed on the display device 40 at night or the like when the dark condition of the visual field is satisfied, but also in the daytime or the like when the bright condition of the visual field is satisfied. Alternatively, the view image I may be displayed on the display device 40. In this modified example 13, in a state where the determination result flag Fyn is “ON” due to the presence / absence of fog, for example, the view image I in which the influence of fog is suppressed by image processing that removes the fog component from the view image I or the like Can be displayed. Further, as a fourteenth modified example of the first to fifth embodiments, the night view function for displaying the view image I at night or the like when the dark condition of the view is satisfied may not be realized.

  As a modification 15 of the third to fifth embodiments, the analysis region Aa of the second embodiment may be adopted. Moreover, as a modification 16 of the first to fifth embodiments, the analysis area Aa may be set at an arbitrary position of the irradiation area Al, for example, the entire area, or the analysis area Aa is changed according to the traveling environment. You may let them. Furthermore, the values of various parameters employed in the first to fifth embodiments and the modifications 1 to 17 can be set to appropriate values as long as the characteristics of the embodiments or modifications are satisfied.

DESCRIPTION OF SYMBOLS 1 Vehicle visibility support apparatus, 2 Vehicle, 3 Light switch, 4a Headlight, 4b Tail light, 5 Fog lamp switch, 6a Front fog lamp, 6b Rear fog lamp, 7 Night view switch, 8 Vehicle speed sensor, 10 Floodlight, 20 Imaging element, 30 Control device, 40 display device, Af field of view, Al irradiation region, Aa analysis region, Aac, Aad partial region, Cth confirmation count, Cies continuous presence / absence determination count, Cno continuous non-determination count, I visual field image, Ion lit image, Ioff unlit Image, N Number of frames taken, Vthl setting speed, Δth criterion, Δthsy, Δthsn Strict value, Δthd relaxation value, ΣLon / N, ΣLoff / N, ΣDon / N, ΣDoff / N Luminance average value

Claims (15)

A vehicle visibility support device for assisting a passenger's vision (Af) in a vehicle (2),
Irradiating means (10) for irradiating near-infrared light toward a predetermined irradiation region (Al) entering the field of view by lighting;
An imaging means (20) for capturing a field-of-view image (I, Ion, Ioff) by receiving the near-infrared light from the irradiation area while the irradiation means is turned on;
Judgment means (30, S70, S701 to S715, S3706, S3708, S3713, S3715, etc.) for determining the presence or absence of fog in the field of view based on the luminance distribution of the irradiation area reflected in the field-of-view image captured by the imaging means. S4706b, S4706c, S5700b, S5700c)
A vehicle visibility support device comprising: The field-of-view image (I) captured by the imaging unit while the irradiation unit is turned on is defined as a lighting image (Ion), and the field-of-view image (I) captured by the imaging unit while the irradiation unit is turned off. ) Is defined as an unlit image (Ioff)
2. The vehicle field of view according to claim 1, wherein the determination unit determines the presence or absence of fog in the field of view based on a difference in luminance distribution of the irradiation area shown in each of the lighting image and the unlighting image. Support device. A calculation unit (30, S60, S601 to S610) for calculating a luminance average value with respect to the luminance distribution of the irradiation area reflected in the field-of-view images captured continuously by the imaging unit;
The determination means determines the presence or absence of fog in the field of view based on the average brightness values (ΣLon / N, ΣLoff / N, ΣDon / N, ΣDoff / N) calculated by the calculation means. The vehicle field-of-view support apparatus according to claim 1 or 2.   The calculation means (30, S40, S401 to S408, S409, S410) decreases the number of frames (N) of the field-of-view image to be calculated as the luminance average value as the traveling speed of the vehicle increases. The vehicle visibility support apparatus as described in any one of Claims 1-3 characterized by the above-mentioned.   The determination means, when one of the determination and non-determination of the fog is continuously performed, determines the one determination and then continuously decreases the other of the determination and non-determination of the fog. The vehicle visibility support device according to any one of claims 1 to 4, wherein the determination of the one is maintained until this time.   The fog lamp of the vehicle is turned on when the determination unit determines that the fog is present, and the fog lamp is turned off when the determination unit determines that the fog is not determined. The vehicle visibility support device according to any one of claims 1 to 5, further comprising lamp control means (30, S90, S100, S110).   The determination means, when one of the determination and non-determination of the fog is continuously made a predetermined number of confirmations, after determining the one determination, the other of the determination and non-determination of the fog The vehicle visibility support device according to claim 6, wherein the one determination is maintained until a number of times greater than the number of confirmations is continuously made.   When the determination means (30, S70, S701 to S705, S707, S709 to S712, S714, S3706, S3708, S3713, S3715) continuously lowers one of the fog determination and non-determination, 8. The criterion for the other determination is strictly set until the other determination is continuously made after the determination of the one determination is confirmed and the other is continuously determined. Vehicle visibility support device. Predicting means (30, S4706a) for predicting the occurrence of fog is further provided,
The determination means (30, S70, S701 to S705, S707 to S715, S4706b, S4706c) that determines the determination when the determination of the presence of fog has been continuously performed for a predetermined number of confirmations, The vehicle visibility support device according to any one of claims 6 to 8, wherein the number of confirmations is reduced when predicted by the prediction means. Predicting means (30, S5700a) for predicting the occurrence of fog is further provided,
The determination means (30, S70, S701 to S715, S5700b, S5700c) is characterized in that, when the generation of the fog is predicted by the prediction means, the criterion for determining whether the fog is present is set loosely. Item 10. The vehicle visibility support device according to any one of Items 6 to 9.   The vehicle visibility support according to any one of claims 6 to 10, wherein the determination means (30, S20) permits the determination of the fog when a bright condition of bright visibility is satisfied. apparatus.   The determination means (30, S40, S401, S402, S50) prohibits the determination of the fog when the traveling speed of the vehicle is less than a predetermined set speed. The vehicle visibility support apparatus as described in any one of Claims.   13. The night vision camera according to claim 1, wherein the imaging unit is a night vision camera that captures the visual field image displayed on the vehicle when a dark dark condition of the visual field is satisfied. The vehicle visibility support apparatus as described.   The said determination means determines the presence or absence of the said fog based on the said luminance distribution of the partial area | region (Aac) including the center part of a horizontal direction among the said irradiation area | regions reflected in the said visual field image. The vehicle visibility support apparatus as described in any one of -13.   The said determination means determines the presence or absence of the said fog based on the said luminance distribution of the partial area | region (Aad) biased to the opposite lane side of the horizontal direction among the said irradiation areas reflected in the said visual field image. Item 14. A vehicle visibility support device according to any one of Items 1 to 13.

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