JP5040895B2 - Visibility situation determination apparatus, program for visibility situation determination apparatus, and visibility situation determination method - Google Patents

Description

  The present invention relates to a visibility status determination device that determines a driver's visibility status from water droplets attached to a windshield.

  Vehicles, particularly automobiles, are provided with wipers for wiping off water droplets adhering to the windshield during rain and the like to ensure the driver's visibility. In recent years, it has been detected using a sensor that water droplets such as raindrops have adhered to the windshield, and the wiping operation of the wiper is automatically controlled by determining the visibility state of the driver.

Conventionally, as an apparatus for determining a visibility situation, for example, there has been an invention described in Patent Document 1. The present invention is intended to detect water droplets adhering to the windshield surface by photographing the front of the vehicle with a CCD camera disposed in the vicinity of the rearview mirror.
JP 2001-141838 A

  However, since such a conventional device is arranged at a position close to the windshield surface, the position of the device itself is out of the driver's view area on the windshield surface so that the device itself does not interfere with the driver's view. For example, it must be placed in the vicinity of the room mirror. For this reason, the determined visibility situation does not always correspond to the actual driver's visibility area. For example, when the running vehicle stops and water that has accumulated on the roof of the vehicle flows into the windshield, it is determined that there was no rain and that there was no rain. There was a case.

  Therefore, in order to accurately determine the driver's visibility state, it is necessary to detect the state of water droplets attached to the driver's visibility region on the windshield surface. In this regard, for example, in the case of a CCD camera, it is conceivable that the camera is installed in a vehicle compartment away from the windshield and photographs water droplets adhering to the driver's field of view on the windshield surface. It is extremely difficult to recognize only water droplets attached to the water.

  The present invention has been made to solve such a problem, and an object thereof is to accurately determine a driver's visibility state.

  The visual field situation determination apparatus according to claim 1 of the present invention made to achieve the above object includes a plurality of detection means and estimation means. The plurality of detection means respectively detect the state of water droplets adhering to the windshield in a plurality of areas sandwiching the driver's field of view on the windshield surface of the host vehicle, and the estimation means are respectively detected by the plurality of detection means. When the state of the water drop is close, it is estimated that the driver's field of view is close to the state of the water drop.

  Here, the state of the water droplet is the area occupied by the water droplet in the region, the average of the area of one water droplet, the dispersion or standard deviation, the number of water droplets, etc. It also means the degree or numerical value that objectively represents the state of water droplets on the premise that the areas are different.

  Moreover, that the state of a water drop is approximate means the case where the degree or numerical value showing the state of a water drop is the same or close to each other.

  Further, when the driver's view area is sandwiched, if there are two detection means, the belt-like area overlaps the view area when the areas detected by the detection means are connected to each other at the shortest distance. If the number of detection means is three or more, when the areas detected by these detection means are respectively connected in a band shape, the outer periphery of the band-like area surrounds the visual field area.

  According to the first aspect of the present invention, when the state of water droplets adhering to a plurality of regions sandwiching the driver's field of view approximates, the driver's field of view region is estimated to be close to the state of the water droplets. Can be accurately determined.

  According to a second aspect of the present invention, in the visibility state determining apparatus according to the first aspect, the detection means takes an image of a water droplet attached to the windshield.

  According to the invention described in claim 2, since the image of the water droplets attached to the windshield is acquired as an image, not only the total area of the water droplets but also the area of one water droplet, the number of water droplets, and the like can be accurately detected. Compared with a conventional light amount sensor that simply detects only the total amount of light, the driver's visibility condition can be determined more accurately.

  According to a third aspect of the present invention, in the visibility situation determining apparatus according to the first or second aspect, the apparatus further comprises a wiper control means, and the wiper control means estimates the wiper wiping operation for wiping the water droplets on the windshield. Therefore, when it is estimated that the driver's field of view is close to the state of the water droplets, the control is performed during rain.

  Here, it is highly likely that the reason why the water droplets are attached is due to rain if the state of the water droplets in the plurality of regions is uniform because the state of the plurality of water droplets is approximate. It is based on what can be said.

  According to the invention described in claim 3, since it is possible to perform wiper control during rainfall after accurately determining that the driver's field of view has deteriorated due to rain, more appropriate wiper control is possible. It becomes.

  According to a fourth aspect of the present invention, in the visual field situation determination apparatus according to any one of the first to third aspects, the collision warning control means is provided, and the collision warning control means determines the driver's visual field area by the estimation means. When it is determined that the state of the water droplet is close and the state of the water droplet detected by the detection means is significantly hindering the driver's field of view, a warning is given to detect the risk that the vehicle will collide with an object. The timing of warning in the collision warning system that emits is changed so as to be earlier than usual.

  Here, the case where it is determined that the driver's field of view is significantly obstructed is, for example, when the total area of the water droplets is equal to or greater than a threshold (for example, 50% of the detection area) from the state of the water droplets in the region. A case where it is judged that the amount of water droplets adhering to the windshield is large (such as heavy rain).

  According to the invention described in claim 4, the amount of water droplets adhering to the windshield is so large that the driver's visibility is extremely poor, and the brake operation and steering operation for avoiding a collision tend to be delayed. Even in a situation where braking is required earlier than usual because the state is not good, warning control for collision avoidance and collision mitigation is appropriately performed.

  According to a fifth aspect of the present invention, in the visibility state determination apparatus according to any one of the first to fourth aspects, the vehicle includes a lane warning control means, and the lane warning control means has a driver's visual field area estimated by the estimation means. When the vehicle deviates from the lane when it is estimated that it is close to the state of water droplets and it is determined from the state of water droplets detected by the detection means that the driver's field of view is significantly obstructed (for example, heavy rain). The warning timing in the lane departure warning system that issues a warning or the driving timing in the lane keeping support system that supports the vehicle traveling in the lane is changed to be earlier than usual.

  According to the fifth aspect of the present invention, the amount of water droplets adhering to the windshield is so large that the driver's visibility is extremely bad and the vehicle is difficult to travel in the lane, and the road surface condition is not good. Even under the situation where the steering wheel operation is necessary, the control is made to enable traveling in the lane appropriately.

  A sixth aspect of the present invention is the visibility status determining apparatus according to any one of the first to fifth aspects, further comprising an inter-vehicle distance control unit, wherein the inter-vehicle distance control unit is configured so that the driver's visual field region includes the water droplets by the estimating unit. When it is determined that the driver's field of view is significantly obstructed (for example, heavy rain) from the state of water droplets estimated to be close to the state and detected by the detection means, the inter-vehicle distance control between the host vehicle and the preceding vehicle is performed. The inter-vehicle time or inter-vehicle distance in the inter-vehicle control system to be performed is made longer than usual.

  According to the invention of claim 6, even if it is better to make the inter-vehicle distance longer than usual because the amount of water droplets adhering to the windshield is large, the visibility situation is remarkably bad and the road surface condition is not good. In addition, it is possible to control the distance from the preceding vehicle.

  The program for a visibility situation determination apparatus according to claim 7 is detected by a plurality of detection units that respectively detect the state of water droplets attached to the windshield in a plurality of areas sandwiching the driver's visibility area on the windshield surface of the host vehicle. When the state of the dropped water drop is approximated, the computer is caused to function as estimation means for estimating that the driver's field of view area is close to the water drop state.

  According to the seventh aspect of the invention, the same effect as that of the first aspect of the invention can be obtained.

  The visibility status determination method according to claim 8 is a detection step for detecting a state of water droplets attached to the windshield in a plurality of areas sandwiching the driver's visibility area on the windshield surface of the host vehicle, and a detection step, respectively. And an estimation step for estimating that the driver's field of view is close to the state of the water droplet when the state of the water droplet is approximate.

  According to the eighth aspect of the invention, the same effect as that of the first aspect of the invention can be obtained.

  Embodiments to which the present invention is applied will be described below with reference to the drawings.

[1 Configuration]
FIG. 1 is a block diagram showing the overall configuration of a rainfall determination system mounted on a vehicle according to this embodiment. This rain determination system includes two rain sensors 1, 2, a visibility determination unit 3, a wiper control device 4, a wiper 5, a CMS-ECU 6, a lane keeping control ECU 7, and an inter-vehicle distance control ECU 8.

  The two rain sensors 1 and 2 are sensors that detect the state of water droplets by taking an image of water droplets attached to the windshield of a vehicle (hereinafter referred to as “own vehicle”) equipped with a rainfall determination system.

  FIG. 2A is an explanatory diagram showing the internal structure of the rain sensors 1 and 2. The rain sensors 1 and 2 are installed on the windshield 10, and include an infrared LED 11, a condenser lens 12, an imaging lens 13, and a camera 14 inside.

  The infrared LED 11 is a light emitting diode that emits infrared light, and the condenser lens 12 and the imaging lens 13 are convex lenses for collecting light. The camera 14 is a CCD (charge coupled device) or CMOS (complementary metal oxide semiconductor) camera for taking a two-dimensional image.

  Infrared light emitted from the infrared LED 11 is collimated by the condenser lens 12 and irradiated from the indoor side of the windshield 10. The portion where no water droplets are attached to the windshield 10 is totally reflected with the same incident angle and reflection angle, so that the imaging lens 13 placed on the opposite side so as to have the same angle as the incident angle receives the reflected light. Then, the image is formed by the action of the lens, and a two-dimensional image is taken by the camera 14. At this time, the infrared light applied to the portion where the water droplets are attached to the windshield 10 is transmitted through and escapes to the opposite side and does not become reflected light. Therefore, the portion corresponding to the image of the water droplet is detected as a black portion in the image. Is done.

  FIG. 2B is a specific example of an image taken by the camera 14. As shown in the figure, the portion where the water droplets are attached becomes a black image and appears in the image. Further, since the camera 14 captures the reflected light obliquely from above, the camera 14 has a shape contracted in the vertical direction as compared with the case of photographing from the front. In order to calculate the area and the like accurately, an image when viewed from the front with correction in the vertical direction is used.

  These two rain sensors 1 and 2 detect the state of water droplets adhering to the area of the front windshield 10 surface of the host vehicle. The areas detected by these two rain sensors 1 and 2 are determined by the driver. Is set to a position sandwiching the field of view.

  FIG. 3 shows a driver's field of view on the surface of the windshield 10. As shown by a dotted line in FIG. 3A, a certain area corresponding to the front of the driver is a view area on the surface of the windshield 10. FIG. 3B is a view of this from the side, but a certain range in the vertical direction from the driver's line of sight is the view area on the surface of the windshield 10.

  FIG. 4 shows a position where the rain sensors 1 and 2 are arranged in the present embodiment. As shown in the figure, for example, when the host vehicle is a right steering wheel, the rain sensor 1 is installed on the right side of the lower side of the windshield 10 (lower part of the field of view), and the rain sensor 2 is placed on the right side of the upper side of the windshield 10 ( Install in the upper part of the field of view. Both the rain sensor 1 and the rain sensor 2 are arranged in a range wiped by the wiper 5 and are in a positional relationship across the driver's field of view. By arranging in this way, the driver's visibility situation can be accurately determined.

  The visibility determination unit 3 compares the approximation of the water droplet states in the two regions obtained from the rain sensors 1 and 2 and estimates that the driver's visibility region is also close to the water droplet state. It is an electronic control unit which judges the visibility condition of.

  The wiper control device 4 is a control device that sends a control signal to the wiper 5 in order to wipe off water droplets and the like adhering to the windshield 10 with the wiper 5. When it rains, the wiping operation of the wiper 5 is executed by a driver's operation or a signal from the visibility determining unit 3. In wiping control of the wiper 5, the visibility situation due to rain or the like is important, and therefore information relating to the visibility situation is sent from the visibility determination unit 3.

  The wiper 5 is a device for wiping off water droplets and the like adhering to the windshield 10.

  The CMS-ECU 6 is an electronic control unit that controls a collision mitigation system and a collision avoidance system that detect a danger that the host vehicle will collide with an object such as a person or an object from a sensor (not shown).

  Specifically, the collision mitigation system applies an automatic brake for warning when the own vehicle may collide with an object, or assists the driver of the own vehicle in brake operation (PBA: Predictive Brake Assist). However, control is performed to change the timing of the alarm brake and assist so as to be earlier than usual.

  In the collision avoidance system, other vehicles and people are detected by sensors, etc., so that the vehicle does not collide, the driver is alerted by alarm or voice, or the steering or brake is controlled. However, control is performed to change these timings to be earlier than usual.

  The lane keeping control ECU 7 is a lane departure warning system that issues an alarm when the host vehicle departs from the lane, and an electronic control unit that performs drive control such as steering control so that the host vehicle travels in the lane.

  Specifically, the lane departure warning system recognizes a lane from the white line on the road surface on which the host vehicle is traveling, and issues a warning when the vehicle deviates from the lane. Control to change to is performed.

  The lane keeping support system controls the travel of the host vehicle so that the host vehicle travels in the lane on the road surface on which the host vehicle is traveling. Control is performed to change the drive timing of this control.

  The inter-vehicle distance control ECU 8 is an electronic control unit that controls the inter-vehicle control system that performs inter-vehicle control with the preceding vehicle. Here, the inter-vehicle time or the inter-vehicle distance is changed according to the visual field situation by the visual field determination unit 3.

  Specifically, the inter-vehicle distance control ECU maintains a constant inter-vehicle distance or inter-vehicle time between the host vehicle and the preceding vehicle, issues an alarm when the distance from the preceding vehicle becomes closer than necessary, Control is performed to separate the vehicle from the preceding vehicle, and control is performed to change the inter-vehicle distance or inter-vehicle time.

  The data bus 9 is a bus for transmitting and receiving data among the visibility determining unit 3, the wiper control device 4, the CMS-ECU 6, the lane keeping control ECU 7, and the inter-vehicle distance control ECU 8.

[2 processing]
Next, processing executed by the rainfall determination system as the present embodiment will be described using a flowchart.

  FIG. 5 is a flowchart showing processing executed by the visual field determination unit 3. This process is a mode in which the wiping operation is automatically controlled by the wiper 5 in a state where the ignition switch of the host vehicle is turned on and power is supplied to the rain determination system including the rain sensors 1 and 2 (auto wiper mode). ). Specifically, the visibility determining unit 3 executes a predetermined program. This process is repeatedly executed at regular time intervals, for example, 33 ms.

  The visual field determination unit 3 first determines whether or not there is a water droplet region in the images acquired from the rain sensor 1 and the rain sensor 2 in S101. When there is no water drop area (S101: NO), the process proceeds to S102, and when there is a water drop area (S101: YES), the process proceeds to S103. Specifically, whether or not there is a water droplet region is determined by whether or not there is a black portion in the images acquired from the rain sensors 1 and 2, and if there is a black portion, it is determined that there is a water droplet region. Become.

  In S103, it is determined whether or not there is a water droplet region for only one of the sensors of the rain sensor 1 and the rain sensor 2. When there is a water drop area for only one sensor (S103: YES), the process proceeds to S102, and when there is a water drop area for both sensors (SS103: NO), the process proceeds to S104.

  FIG. 6 is an explanatory diagram showing the determination in S103. For example, as shown in FIG. 6 (a), in the image of the rain sensor 1, a constant water droplet image is recognized, but in the case where the rain sensor 2 image is not recognized at all, the water sensor image of the rain sensor 1 is There is a high possibility that the water has accumulated due to factors other than rainfall, such as when water accumulated on the roof of the own vehicle flows or when splashed muddy water adheres when the traveling vehicle stops. Therefore, it is not determined that the field of view is deteriorated due to rainfall, and the wiping operation of the wiper 5 is not executed.

  On the other hand, as shown in FIG. 6B, when the image of the rain sensor 1 and the image of the rain sensor 2 are similarly recognized by water droplets, it is highly likely that these water droplets are due to rain. Therefore, it is necessary to wipe off the water droplets adhering to the driver's view continuously for a certain time. In this case, the closer the water droplet state of the rain sensor 1 and the water droplet state of the rain sensor 2 are, the more closely the water droplets are attached and the higher the possibility of rain. become.

  In S104, it is determined whether or not the difference between the total area of the water droplets of the rain sensor 1 and the total area of the water droplets of the rain sensor 2 is smaller than the threshold A. If the difference in the total area is not smaller than the threshold A (S104: NO), the process proceeds to S105, and if smaller than the threshold A (S104: YES), the process proceeds to S106. The total area of the water droplet here is a value obtained by adding all the numbers of pixels of the black portion corresponding to the image of the water droplet when there are one or more images of the water droplet.

  The thresholds A to D are reference values for comparing the state of water droplets in the images obtained from the rain sensors 1 and 2, and are set according to the accuracy of the sensor. The thresholds A to D may be configured to be changeable by the driver.

  In S106, it is determined whether or not the difference between the average area per water droplet of the rain sensor 1 and the average area per water droplet of the rain sensor 2 is smaller than the threshold value B. If the average difference is not smaller than the threshold value B (S106: NO), the process proceeds to S105, and if smaller than the threshold value B (S106: YES), the process proceeds to S107.

  In S107, it is determined whether or not the difference between the variance value of the area per water droplet of the rain sensor 1 and the variance value of the area per water droplet of the rain sensor 2 is smaller than the threshold value C. If the variance value difference is not smaller than the threshold value C (S107: NO), the process proceeds to S105, and if it is smaller than the threshold value C (S107: YES), the process proceeds to S108.

  In S108, it is determined whether or not the difference between the total number of water droplets of the rain sensor 1 and the total number of water droplets of the rain sensor 2 is smaller than the threshold value D. If the difference in the total number of water droplets is not smaller than the threshold D (S108: NO), the process proceeds to S105, and if smaller than the threshold D (S108: YES), the process proceeds to S109. That is, when the state of the water droplets detected by the two rain sensors 1 and 2 are approximate, the process proceeds to S109.

  In S109, a control signal is sent to the wiper control device 4 so as to perform a normal wiper operation. After S109, the process ends.

  The normal wiper operation is normal wiper control when it is determined that there is rain because the state of water droplets attached to the two areas of the rain sensors 1 and 2 is approximate. Here, since the rain amount can also be detected by the rain sensors 1 and 2, the intermittent time of the wiper 5 may be controlled according to the rain amount.

  On the other hand, in S105, a control signal is sent to the wiper control device 4 to perform a temporary wiper operation. After S105, the process ends.

  This temporary wiper operation is a process in which it is not always possible to determine with certainty that there is rainfall because there are some differences in the state of the water droplets attached to the two areas of the rain sensors 1 and 2. The operation is executed with an intermittent time longer than the wiping operation of the wiper 5. Accordingly, it is possible to prompt the driver to determine whether to continuously wipe the wiper or stop the wiper.

  In S102, since there is no water drop area for at least one, it is determined that there is no rain, and a signal indicating that the wiper operation is not performed is sent to the wiper control device 4. The wiper control device 4 does not perform any new processing unless the wiper 5 is wiped, but if the wiper operation is performed in the auto wiper mode, it is determined that the rain has stopped and Stop wiping operation. After S102, the process is terminated.

  FIG. 7 is a flowchart showing a process executed by the visibility determining unit 3, and here, a control signal is sent to the CMS-ECU 6, the lane keeping control ECU 7 and the inter-vehicle distance control ECU 8. In this process, when the ignition switch of the host vehicle is turned on and power is supplied to each of the ECUs 6, 7, and 8, the visual field determination unit 3 starts the process. This process is repeatedly executed at regular time intervals, for example, 33 ms.

  First, in S201, it is determined whether or not the rain sensors 1 and 2 have a water droplet area and the states of both are substantially the same. When not seeing this (S201: NO), it progresses to S202, and when satisfying (S201: YES), it progresses to S203. Specifically, the processing of S101, S103, S104, S106, S107, and S108 in the flowchart shown in FIG. 5 is sequentially performed, and whether or not the state of water droplets detected by the two rain sensors 1 and 2 is approximate. It will be judged. As described above, since the state of the water droplets of the rain sensors 1 and 2 is approximate, the state of the water droplet in the driver's field of view can be estimated, and the possibility of rain is high.

  Next, in S203, it is determined whether or not the total area of the water droplets is larger than the threshold value E. If it is not larger than the threshold E (S203: NO), the process proceeds to S204, and if it is larger (S203: YES), the process proceeds to S205. Here, the amount of rainfall is determined from the total area of the water droplets. This threshold value E is determined to be heavy rain on the assumption that it is raining. If it is determined that there is heavy rain here, the visibility will be considerably deteriorated, and the road surface condition may be deteriorated due to heavy rain, so processing for changing the timing of each system will be performed. .

  In S205, a control signal for setting the alarm timing in the collision mitigation system and the collision avoidance system to be earlier than usual is sent to the CMS-ECU 6. After S205, the process proceeds to S206. After S205, it is determined that the driver's field of view is significantly hindered by heavy rain this time, and the driver's field of view is significantly obstructed by heavy rain for each of the ECUs 6, 7, and 8. A control signal is sent so as to control. Further, when the control is already performed when the driver's field of view is significantly obstructed by heavy rain, no particular change is made.

  In S206, a control signal for setting the warning timing in the lane departure warning system and the driving timing in the lane keeping support system to the lane keeping control ECU 7 is set earlier than usual. After S206, the process proceeds to S207.

  In S207, a control signal for setting the inter-vehicle time or inter-vehicle distance longer than usual for inter-vehicle control with the preceding vehicle is sent to the inter-vehicle distance control ECU 8. After S207, the process ends.

  On the other hand, in S204, it is determined whether or not the total area of the water droplets at the time of the previous determination is larger than the threshold value E. If the previous time is larger than the threshold E (S204: YES), the process proceeds to S208. If the previous time is not larger than the threshold E (S204: NO), the process proceeds to S202. In S204, it is determined whether the state of heavy rain has changed to normal rain by determining the total area of the previous water droplets.

  In S208, a control signal for returning the alarm timing in the collision mitigation system and the alarm timing in the collision avoidance system to normal settings is sent to the CMS-ECU 6. After S208, the process proceeds to S209. After S208, it was determined that there was heavy rain last time, but this time it is determined that there is no heavy rain, and a control signal is sent to each ECU 6, 7, 8 to return to normal control. It will be.

  In S209, a control signal for returning the alarm timing in the lane departure warning system and the drive timing in the lane maintenance support system to the normal setting is sent to the lane keeping control ECU 7. After S209, the process proceeds to S210.

  In S210, the inter-vehicle distance control ECU 8 performs processing for returning the inter-vehicle time or the inter-vehicle distance to the normal setting for inter-vehicle control with the preceding vehicle. After S210, the process ends.

  S202 is a case where there is no need to change the control of the ECUs 6, 7, and 8, and the process is terminated as it is.

[3 effects]
As described above, according to the rain determination system of the present embodiment, the two rain sensors 1 and 2 detect the state of water droplets attached to the two regions sandwiching the driver's field of view as an image, and detect it. When the state of the water droplet is approximate, it is estimated that the state of the water droplet in the driver's field of view is close to that state. In order to determine the presence or absence of rain based on such estimation (S101, S103, S104, S106, S107, S108, S201), the driver's visibility situation can be accurately determined.

  Moreover, since the deterioration of the visibility situation due to rain is accurately determined and the control of the wiping operation of the wiper 5 is the control at the time of rain (S105, S109), more appropriate wiper control is possible.

  Further, when it is determined that the driver's field of view is significantly hindered by heavy rain (S203), the warning timing in the collision mitigation system and collision avoidance system is made earlier than usual (S205). Appropriate collisions are possible even in situations where the brakes and steering wheel operations for avoiding collisions are very slow and the brakes and steering wheel operations are delayed, and the road surface is not good, so braking is required earlier than usual. Alarm control for avoidance and collision mitigation is performed.

  In order to make the warning timing in the lane departure warning system and the driving timing in the lane maintenance support system earlier than usual (S206), the driver's visibility is remarkably bad due to heavy rain, and the road surface condition is not good. Even under a situation where a steering wheel operation is necessary, the control is made to enable traveling in the lane appropriately.

  Furthermore, since the inter-vehicle time or inter-vehicle distance in the inter-vehicle control with the preceding vehicle is set longer than usual (S207), the visibility situation is remarkably bad due to heavy rain, and the road surface condition is not good, so the inter-vehicle distance is made longer than usual. Even when it is better to perform the control, it is possible to appropriately maintain the distance from the preceding vehicle.

[4 Correspondence with Claims]
Note that the rain sensors 1 and 2 of the present embodiment correspond to detection means, and S101, S103, S104, S106, S107, S108, and S201 executed by the visual field determination unit 3 correspond to estimation means.

  Further, S109 executed by the visual field determination unit 3 corresponds to a wiper control unit, S205 executed by the visual field determination unit 3 is a collision warning control unit, S206 executed by the visual field determination unit 3 is a lane warning control unit, and the visual field determination unit 3 S207 to be executed corresponds to the inter-vehicle distance control means.

[5 Other forms]
As mentioned above, although one Embodiment of this invention was described, it cannot be overemphasized that this invention can take a various form.

  For example, as shown in FIG. 8A, two sensors are used as the position of the region where the state of the water droplet is detected by the rain sensor, and the upper side central portion (upper left portion of the viewing region) and the lower right portion (viewing region) May be arranged so that the driver's field of view is sandwiched diagonally by two rain sensors. Further, as shown in FIG. 8 (b), the three sensors are arranged at the center of the upper side of the windshield 10 (upper left of the viewing area), the center of the lower side (lower left of the viewing area), and the lower right side (lower right of the viewing area). ) And may be disposed so as to sandwich the driver's field of view. Of course, four or more sensors may be used.

  Moreover, in the said embodiment, although the state of the water droplet was detected using the image which image | photographed the image of the water droplet, you may detect a light quantity with the photodiode (light quantity sensor) which is the conventional rain sensor. Even in this case, since at least the total area of the portion to which the water droplets are attached can be detected, the state of the water droplets can be compared.

  Further, in the above-described embodiment, the visibility determination unit 3 is configured to execute the processing of the visibility status determination device. However, for example, a part of the processing is distributed to the wiper control device 4 and is configured to be accessible on the network. It is also possible to distribute the processing to other electronic control units.

It is a block diagram which shows the whole structure of the rainfall determination system as this embodiment. It is explanatory drawing which shows the internal structure of a rain sensor. It is explanatory drawing which shows a driver | operator's visual field area | region in a windshield surface. It is explanatory drawing which shows the position where a rain sensor is arrange | positioned. It is a flowchart which shows the wiper control process which a visual field determination part performs. It is explanatory drawing which shows a mode that the state of a visual field area | region is estimated from the image obtained from a rain sensor. It is a flowchart which shows each system control which a visual field determination part performs. It is explanatory drawing which shows the position in the case of arrange | positioning a several rain sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 ... Rain sensor, 3 ... Visibility determination part, 4 ... Wiper control apparatus, 5 ... Wiper, 6 ... CMS-ECU, 7 ... Lane maintenance control ECU, 8 ... Inter-vehicle distance control ECU, 9 ... Data bus, 10 ... Windshield, 11 ... Infrared LED, 12 ... Condensing lens, 13 ... Imaging lens, 14 ... Camera

Claims (8)

A plurality of detection means for respectively detecting the state of water droplets attached to the windshield in a plurality of areas sandwiching the driver's field of view on the windshield surface of the host vehicle;
A visual field situation determination device comprising: an estimation unit that estimates that the visual field area of the driver is close to the state of the water droplet when the state of the water droplet detected by each of the plurality of detection units approximates .   The visual field condition determination apparatus according to claim 1, wherein the detection unit captures an image of water droplets attached to the windshield.   The wiper wiping operation for wiping off the water droplets on the windshield is provided with wiper control means for controlling the rain when the estimation means estimates that the driver's field of view is close to the state of the water drops. The visibility situation determining apparatus according to claim 1 or 2, wherein   When it is determined by the estimation means that the driver's field of view is close to the state of the water droplet, and it is determined that the driver's visual field is significantly hindered from the state of the water droplet detected by the detection means, A collision warning control means for changing the timing of the warning so as to be earlier than usual in a collision warning system that issues a warning by detecting the danger that the host vehicle collides with an object is provided. Item 4. The visual field situation determination device according to any one of Items3 to 4.   When it is determined by the estimation means that the driver's field of view is close to the state of the water droplet, and it is determined that the driver's visual field is significantly hindered from the state of the water droplet detected by the detection means, Change the alarm timing in the lane departure warning system that issues an alarm when the host vehicle departs from the lane or the driving timing in the lane maintenance support system that supports the host vehicle traveling in the lane so that it is earlier than usual. The visibility condition determination apparatus according to any one of claims 1 to 4, further comprising a lane warning control unit.   When it is determined by the estimation means that the driver's field of view is close to the state of the water droplet, and it is determined that the driver's visual field is significantly hindered from the state of the water droplet detected by the detection means, The field of view according to any one of claims 1 to 5, further comprising an inter-vehicle distance control means for making an inter-vehicle time or inter-vehicle distance longer than usual in an inter-vehicle control system that performs inter-vehicle control between the host vehicle and a preceding vehicle. Situation judgment device.   When the state of the water droplets respectively detected by a plurality of detection means that respectively detect the state of the water droplets attached to the windshield in a plurality of regions sandwiching the driver's field of view on the windshield surface of the host vehicle, A program for a visual field situation determination apparatus, which causes a computer to function as estimation means for estimating that a driver's visual field area is close to the water droplet state. A detection step of detecting the state of water droplets attached to the windshield in a plurality of areas sandwiching the driver's field of view on the windshield surface of the host vehicle;
A visibility state determination method comprising: an estimation step of estimating that the driver's visual field region is close to the water droplet state when the state of the water droplets detected in the detection step is approximate.