JP5287155B2 - Water repellent effect determination device, program for water repellent effect determination device, and water repellent effect determination method - Google Patents

Description

  The present invention relates to a water repellent effect determination device that determines a water repellent effect of a windshield of a vehicle.

  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. Generally, if the rain is heavy, the number of wiping operations per unit time of the wiper is increased. If the rain is light, the number of wiping operations is decreased. However, if the water repellent effect by the windshield is large, the number of wiping operations by the wiper is reduced. be able to. As described above, it is important to accurately determine how much the water repellent effect is generated in controlling the wiping operation by the wiper.

Conventionally, for example, there has been an invention described in Patent Document 1 as an apparatus for determining a water repellent effect. In the present invention, the water repellent effect is determined by detecting a load applied to the wiper as an electric signal. That is, if the wind-repellent effect of the windshield is large, the load applied to the wiper is reduced. Conversely, if the water-repellent effect is small, the load applied to the wiper is increased, so that the water-repellent effect can be determined.
JP-A-8-282447

  However, such a conventional technique has a problem in that the water repellent effect cannot be accurately determined because the detected electrical signal is affected by other factors. That is, the load applied to the wiper is greatly influenced not only by the water repellent effect but also by the amount of rainfall. Therefore, if an attempt is made to accurately determine the water repellent effect on the premise of this conventional technique, the rainfall amount must be detected accurately. However, it is extremely difficult to grasp the load applied to the wiper by the change of the electric signal in consideration of the rainfall amount, and the error becomes large. Therefore, there is a high possibility that it is judged that there is actually no water repellency even though there is no water repellency, or that there is no water repellency even though there is water repellency. .

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a water repellent effect determination device capable of accurately determining the water repellent effect of a windshield.

The water repellent effect detection apparatus according to claim 1 of the present invention made to achieve the above object includes an acquisition means, a detection means, and a determination means. Then, the acquisition means irradiates infrared light from the vehicle interior side so as to be totally reflected on the surface of the windshield of the host vehicle, and takes an image of water droplets attached to the windshield irradiated with the infrared light . An image is acquired, and the detection unit detects the roundness of the image of the water droplet from the image acquired by the acquisition unit, and the determination unit determines that the image of the water droplet is a perfect circle based on the roundness detected by the detection unit. It is determined that the degree of water-repellent effect is greater as the value is closer to.

  Here, the image of the water droplet refers to the shape of the water droplet that can be obtained from the reflected light when the water droplet attached to the windshield is irradiated with light from the back side of the windshield, but what if the shape of the water droplet is obtained? For example, the shape of the water droplet may be obtained by directly photographing the water droplet through the windshield.

  Roundness refers to the magnitude of deviation from a geometrically correct circle of a circular feature. Generally, when a circular feature is sandwiched between two concentric geometric circles, the distance between the concentric circles is the smallest. It is expressed by the difference between the radii of two circles. Here, it is an index that objectively indicates how close the waterdrop image in the image is to a perfect circle. For example, in image processing, generally, (4π × area) / (contour length squared) can be used as the roundness for one water drop image, but the error of the contour length in image processing is minimized. Therefore, (area) / (contour length) can also be used as the roundness. In this case, it is assumed that the area is constant to some extent, but since the contour length is shorter as it is closer to a perfect circle, it means that the larger the calculated value is, the closer it is to a perfect circle.

  As for the degree of the water repellent effect, the roundness may be expressed as a numerical value, or may be divided into a plurality of levels. Further, it may be determined whether or not a water repellent effect is generated as compared with a predetermined value.

  The water droplets attached to the windshield have the property of becoming closer to a sphere as the water repellency effect by the windshield is larger.As a result, the closer the water drop image is to a perfect circle, the more water repellency effect becomes. It means that it is prominent.

  According to the first aspect of the present invention, it is determined from the image of the water droplets actually attached to the windshield that the degree of the water repellent effect is greater as it is closer to a perfect circle. It is possible to accurately determine whether this has occurred.

Further, in the first aspect of the invention, the detecting means converts the image acquired by the acquiring means into an image viewed from the front to detect roundness.

According to the first aspect of the present invention, even if the image is taken from an oblique direction, it is converted into an image viewed from the front, so that the roundness can be accurately detected, and thus the water repellent effect is accurately determined. it can.

According to a second aspect of the invention, the water repellent effect judging apparatus according to claim 1 Symbol placement, the detection means, when the image of a plurality of water droplets present in the image acquired by the acquisition means, a plurality of water droplets The average roundness of the image is defined as the roundness detected by the detection means.

According to the second aspect of the present invention, the water repellent effect can be accurately determined even when a plurality of water droplets are present in the image.

According to a third aspect of the present invention, in the water repellent effect determination device according to the first or second aspect , the detection means detects the roundness of the image of the water droplet as a numerical value, and further includes a storage means. The storage means stores the roundness detected by the detection means in the internal storage device together with the date and time.

According to the invention described in claim 3 , since the roundness is stored together with the date and time, for example, verification of how long the water-repellent effect lasts from the relationship between the passage of date and time and the decrease in the water-repellent effect. Or predict when a new water-repellent finish is needed.

In the water repellent effect judging device according to claim 4, acquisition unit, an image of water drops attached to the windshield of the vehicle traveling obtains a plurality of images taken over time, determining means, the water droplets In the first determination that the degree of water repellent effect is greater as the image is closer to a perfect circle, and when the traveling speed of the host vehicle is greater than or equal to a predetermined value, the time elapses from a plurality of images acquired by the acquisition means. The accompanying movement of the water droplet is detected, and a second determination is made that determines that the degree of the water-repellent effect is greater as the movement of the water droplet is upward.

  Here, the upward direction means a case where the windshield surface moves upward from the horizontal direction, and it does not matter whether the glass surface is in the upper right direction or the upper left direction.

  Also, the water droplets attached to the windshield have a smaller contact surface with the windshield as the water repellency effect of the windshield increases. It becomes easy to move by the flow of air received. That is, the phenomenon that the water droplet moves upward due to the air flow against the gravity is that the contact surface between the water droplet and the windshield is small and the two repel each other, that is, the water repellent effect is more prominent. Means that.

  In addition, when it is determined that the degree of water repellent effect is greater as the movement of water drops is higher, the degree of water repellent effect can be expressed as a numerical value or multiple levels from the angle of water drop movement. In the upward direction, it is possible to determine only whether or not there is a water repellent effect, such as having a water repellent effect.

According to this invention of Claim 4, since it determines with the degree of water-repellent effect being so large that the motion of the actual water droplet adhering to a windshield becomes upwards, the water-repellent effect of a windshield is determined correctly. Can do.

According to a fifth aspect of the present invention, in the water repellent effect determining apparatus according to the fourth aspect , the determining means determines the presence or absence of the water repellent effect, and in the second determination, the image acquired by the acquiring means If there is an image of a plurality of water droplets, if any one of the plurality of water droplets moves upward, it is determined that there is a water repellent effect.

According to the fifth aspect of the present invention, the water repellent effect can be accurately determined even when a plurality of water droplets are present in the image.

The invention according to claim 4 determines the water repellent effect when the traveling speed of the host vehicle is equal to or higher than a predetermined value as described above .

According to the invention of claim 4 , it is possible to prevent erroneous determination that there is no water repellent effect in a low speed state by not performing determination at a low speed at which water droplets do not move regardless of the presence or absence of the water repellent effect. This eliminates the need for unnecessary processing in a low-speed state where the water repellent effect cannot be detected, and makes the determination more efficient.

A sixth aspect of the present invention is the water repellent effect determination device according to any one of the first to fifth aspects, further comprising a control means, the control means having a high degree of water repellent effect determined by the determination means. Accordingly, the number of wiping operations per unit time of the wiper for wiping the water droplets on the windshield is reduced.

According to the sixth aspect of the invention, it is possible to appropriately control the wiper wiping operation in accordance with the accurately determined water repellent effect.

The invention according to claim 7 is a program for a water repellent effect determination device, which irradiates infrared light from the vehicle interior side so as to be totally reflected on the surface of the windshield of the host vehicle, and is irradiated with the infrared light. acquisition means for acquiring an image obtained by photographing the image of the water droplets attached to the windshield, the image acquired by the acquisition means, converted into an image viewed from the front, the roundness of the water droplets image from the converted image detection was Based on the roundness detected by the detection means and the roundness detected by the detection means, the computer is caused to function as a judgment means for judging that the degree of the water repellent effect is greater as the image of the water droplet is closer to a perfect circle.

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

The invention according to claim 8 is a water repellent effect determination method, in which infrared light is irradiated from the vehicle interior side so as to be totally reflected on the surface of the windshield of the host vehicle, and the front irradiated with the infrared light. An acquisition step of acquiring an image obtained by photographing an image of a water droplet attached to glass, and a detection step of converting the image acquired in the acquisition step into an image viewed from the front and detecting the roundness of the image of the water droplet from the converted image And a perfect circle determination step for determining that the degree of the water repellent effect is greater as the image of the water droplet is closer to the perfect circle based on the roundness detected in the detection step.

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

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

<Configuration>
FIG. 1 is a block diagram showing an overall configuration of a wiper control system mounted on a vehicle as a first embodiment.

  The wiper control system includes a rain sensor 1, a wiper control device 2, a wiper 3, a diagnosis ECU 4, a data storage unit 5, a navigation ECU 6, a vehicle speed sensor 7, and a data bus 8.

  The rain sensor 1 is a sensor that detects water droplets, and is installed on the indoor side surface of the windshield near the room mirror of a vehicle (hereinafter referred to as “own vehicle”) equipped with a wiper control system. . The rain sensor 1 includes a data control unit 9 therein. The data control unit 9 acquires an image obtained by capturing an image of a water droplet attached to the windshield, and determines how much the water repellent effect is generated on the windshield based on the shape of the water droplet and the movement of the water droplet.

  FIG. 2A is an explanatory diagram showing the internal structure of the rain sensor 1. The rain sensor 1 is installed on the windshield 11, and includes an infrared LED 12, a condensing lens 13, an imaging lens 14, and a camera 15 in addition to the data control unit 9.

  The infrared LED 12 is a light emitting diode that emits infrared light, and the condenser lens 13 and the imaging lens 14 are convex lenses for collecting light. The camera 15 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 12 is collimated by the condenser lens 13 and irradiated from the indoor side of the windshield 11. Since the portion where no water droplets are attached to the windshield 11 is totally reflected with the same incident angle and reflection angle, the imaging lens 14 installed on the opposite side so as to have the same angle as the incident angle receives the reflected light. Then, a two-dimensional image is formed by the camera 15 by the action of the lens. At this time, since the infrared light applied to the portion where the water droplet is attached to the windshield 11 passes through and escapes to the opposite side and does not become reflected light, 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 photographed by the camera 15. 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 15 captures reflected light obliquely from above, the camera 15 has a shape contracted in the vertical direction as compared with the case of photographing from the front.

  The camera 15 continuously captures images at a constant time interval, for example, 33 ms, while the data control unit 9 of the rain sensor 1 executes the process of determining the water repellent effect.

  The wiper control device 2 is a control device that sends a control signal to the wiper 3 in order to wipe off water droplets and the like adhering to the windshield 11 with the wiper 3. When it rains, the wiper 3 is wiped by a driver's operation or a signal from the rain sensor 1. In wiping control of the wiper 3, it is important how much the water repellent effect is generated by the windshield 11, and therefore information on the water repellent effect is sent from the rain sensor 1.

  The wiper 3 is a device for wiping off water droplets adhering to the windshield 11.

  The diagnostic ECU 4 is an electronic control unit that receives signals from various sensors (not shown) and diagnoses the current state of the host vehicle. In this wiper control system, a decrease in the water repellent effect by the windshield 11 is detected and notified to the driver.

  The data storage unit 5 is a storage device that stores detection values and the like sent to the diagnosis ECU 4. Here, a numerical value representing how much the water-repellent effect is generated and the date and time of detection are stored as data. The stored data is read out by the diagnostic ECU 4 as necessary, for example, to verify how long the water repellent effect lasts from the relationship between the passage of time and the water repellent effect. Or predict when new water repellent treatment will be needed.

  The navigation ECU 6 is an electronic control unit that includes a GPS receiving unit 10 and provides services such as road guidance to the driver. The navigation ECU 6 acquires the absolute time sent from the GPS satellite via the GPS receiver 10, and the acquired absolute time is stored in the data storage unit 5 together with the degree of the water repellent effect.

  The vehicle speed sensor 7 is a sensor for detecting the traveling speed of the host vehicle, and the traveling speed detected by the vehicle speed sensor 7 is sent to the rain sensor 1 or the like via the data bus 8.

  The data bus 8 is a bus for transmitting and receiving data among the rain sensor 1, the wiper control device 2, the diagnosis ECU 4, the navigation ECU 6, and the vehicle speed sensor 7.

<Processing>
Next, processing executed by the wiper control system as the first embodiment will be described using a flowchart.

  FIG. 3 is a flowchart showing processing executed by the data control unit 9 of the rain sensor 1. This process is started when the ignition switch of the host vehicle is turned on and power is supplied to the wiper control system including the rain sensor 1. Specifically, the data control unit 9 executes a predetermined program. This process is repeatedly executed at regular time intervals, for example, 33 ms.

  First, in S101, the data control unit 9 acquires the image of the windshield 11 from the camera 15, calculates the roundness from the black portion corresponding to the image of the water droplet in the image, and calculates the roundness and the predetermined predetermined value. By comparing the value, it is determined whether or not it is close to a perfect circle. If it is not close to a perfect circle (S101: NO), the process proceeds to S103. If it is close to a perfect circle (S101: YES), the process proceeds to S102.

  FIG. 4 is an explanatory view showing the internal structure of the rain sensor 1. As shown in the figure, since the infrared light emitted from the infrared LED 12 is irradiated on the windshield 11 from obliquely below, The obtained image is reduced in the vertical direction. Therefore, it is necessary to correct in the vertical direction and convert it to an image when viewed from the front. That is, FIG. 5A shows an image taken by the camera 15, but by correcting the image in the vertical direction, an image when viewed from the front shown in FIG. 5B can be obtained. Specifically, when the angle between the shooting direction of the camera 15 and the windshield 11 is α, the entire image may be enlarged in the vertical direction by (1 / sin α).

  Further, as shown in FIG. 5B, when there is a water repellent effect, the shape is close to a perfect circle and a black portion appears in the image. However, when the water repellent effect is not recognized, for example, FIG. As shown in c), the shape appears far from a perfect circle.

  FIG. 6 is an explanatory diagram illustrating an image obtained by capturing an image of a water droplet. The process for calculating the roundness is performed in pixel units in the image processing.

  In FIG. 6, the gray portion is the contour portion of the water drop image, and the black portion is the inside of the water drop image. First, the area of the black part including the gray part is calculated in units of pixels. The number of pixels in the gray portion is set as the actual contour length. As the roundness, (4π × area) / (contour length squared) is an accurate value. However, in order to minimize the error of the contour length in image processing, the roundness is expressed as (area) / ( (Contour length) is used. In this case, it is assumed that the area is constant to some extent, but since the contour length is shorter as it is closer to a perfect circle, it means that the larger the calculated value is, the closer it is to a perfect circle. When the areas are greatly different, the roundness can be calculated under the same standard by correcting the area.

  By comparing this roundness with a predetermined value determined in advance, it is determined how close the image of the water droplets adhering to the windshield 11 is, and if it is close to a perfect circle, there is a water repellent effect. Judge.

  In addition, as shown in FIGS. 5A and 5B, there may be a plurality of water droplets in the image. In such a case, an average value of roundness is taken for a plurality of water droplet images, and the presence or absence of a water repellent effect is determined by the average value.

  Next, in S102, when it is determined in S101 that the shape of the water droplet is close to a perfect circle, it is determined that there is a water repellent effect, and data for notifying the wiper control device 2 via the data bus 8 is provided. Send. After S102, the process is terminated.

  In S103, it is determined from the traveling speed obtained from the vehicle speed sensor 7 whether the host vehicle is at a predetermined speed, for example, 60 km / h or more. If the hourly speed is 60 km or more (S103: YES), the process proceeds to S104. If the hourly speed is not 60 km or more (S103: NO), the process proceeds to S106.

  In S104, it is determined whether or not there is a movement in the upward direction with the passage of time for the water droplets of the plurality of images. If there is an upward movement of the water droplet (S104: YES), the process proceeds to S105, and if there is no upward movement of the water drop (S104: NO), the process proceeds to S106.

  FIG. 7 is an explanatory diagram showing the processing performed in S104. As shown in FIG. 7 (a), with the passage of time, the image of the water droplet in the image is moving upward from the horizontal. In such a case, it is determined that the water droplet has an upward movement. (S104: YES).

  FIG. 7B is an explanatory diagram when there are a plurality of water droplets. When there are a plurality of water droplet images in the image, if any one of the water droplets moves upward, it is determined in S104 that the water droplet has an upward movement. become.

  Next, in S105, it is determined that there is a water repellent effect as in S102, and data to that effect is transmitted to the wiper control device 2 and the process is terminated.

  In S106, it is determined that there is no water repellent effect, data to that effect is transmitted to the wiper control device 2, and the process ends.

  Next, processing executed by the wiper control device 2 will be described.

  FIG. 8 is a flowchart showing processing executed by the wiper control device 2 in response to S102, S105, S106, etc. in FIG. This processing is performed in a mode (auto wiper mode) in which the wiping operation by the wiper 3 is turned on and the intermittent time is automatically changed while power is supplied to the wiper control system including the wiper control device 2. To begin. Specifically, the wiper control device 2 executes a predetermined program. This process is also repeatedly executed at a constant time interval, for example, 33 ms.

  First, in S201, data representing the presence or absence of a water repellent effect is received from the rain sensor 1, and it is determined whether or not there is a water repellent effect. When there is no water repellent effect (S201: NO), the process proceeds to S202, and when there is a water repellent effect (S201: YES), the process proceeds to S203.

  In S202, the auto wiper mode is set to the normal mode, and the process proceeds to S204. That is, if the wiping operation has been performed in the normal mode until then, the operation is continued as it is, and if the wiping operation has been performed in the water repellent mode until then, the mode is changed to the normal mode.

  FIG. 9A shows the intermittent time in the normal mode. If the water repellent effect by the windshield 11 is not generated, the number of wipes of the wiper 3 per unit time increases as the traveling speed of the host vehicle increases, and the intermittent time also decreases.

  On the other hand, in S203, the auto wiper mode is set to the water repellent mode, and the process proceeds to S204. That is, if the wiping operation has been performed in the normal mode until then, the mode is changed to the water repellent mode, and if the wiping operation has been performed in the water repellent mode, the operation is continued as it is.

  FIG. 9B shows an intermittent time in the water repellent mode. When the water repellent effect by the windshield 11 is generated, the number of wipes of the wiper 3 per unit time can be reduced, so that the intermittent time becomes longer as a whole compared to the normal mode. In this case, the intermittent time is lengthened as the traveling speed of the host vehicle increases. That is, when the water repellent effect is generated, the effect of water droplets scattering due to the flow of air increases as the traveling speed of the host vehicle increases, so that the intermittent time can be controlled. A configuration in which the wiping operation of the wiper 3 itself is not necessary when the speed of the host vehicle is high or the water repellent effect is prominent is also conceivable.

  In S204, it is determined whether or not the wiping operation by the wiper 3 or the auto wiper mode is turned off. If the wiping operation or the auto wiper mode is turned off (S204: YES), the process is terminated as it is. If not turned off (S204: NO), the process returns to S201.

<Effect>
As described above, according to the wiper control system of the first embodiment, it is determined from the image of water droplets actually attached to the windshield 11 that there is a water repellent effect when it is close to a perfect circle (S101). The water repellent effect of the windshield can be accurately determined. As a result, appropriate wiper control can be realized.

  In addition, even if the image is taken obliquely with respect to the windshield 11, it is converted to a front view image and it is determined whether or not it is close to a perfect circle. Can be determined.

  Further, when there are a plurality of water droplet images, the water repellent effect is determined by the average value for the roundness, and therefore accurate determination is possible.

  Further, when it is determined that the image of water droplets adhering to the windshield 11 moves upward as time passes (S104), the wiper 3 is controlled, so that the water repellent effect is also accurately obtained. After the determination, it is possible to appropriately control the operation of the wiper 3.

  Further, when a plurality of water droplets adhere to the windshield 11, it is determined that there is a water repellent effect if there is even one water droplet that moves upward, so that it is accurately grasped that there is a water repellent effect. Can do.

<Correspondence with Claims>
In the first embodiment, S101 executed by the data control unit 9 corresponds to an acquisition unit and a detection unit, and S102, S105, and S106 executed by the data control unit 9 correspond to a determination unit, and the wiper control device S203 executed by 2 corresponds to the control means.
[Second Embodiment]
Next, the wiper control system of the second embodiment will be described.

  The wiper control system of the second embodiment is different from the first embodiment only in the process executed by the data control unit 9. Therefore, this difference will be described, and the description of the common points with the first embodiment will be omitted.

  FIG. 10 is a flowchart showing processing executed by the data control unit 9 as the second embodiment. Here, in addition to determining the water repellent effect of the windshield 11, the deterioration of the water repellent effect due to the passage of time is recorded. As in the first embodiment, this process is started when the ignition switch of the host vehicle is turned on and power is supplied to the wiper control system including the wiper control device 2. Specifically, the data control unit 9 executes a predetermined program. This process is also repeatedly executed at a constant time interval, for example, 33 ms.

  First, in S301, the image of the windshield 11 is acquired from the camera 15, and the area of the black portion corresponding to the water droplet image in the image is calculated in units of pixels. Here, the description will be made on the assumption that there is one water droplet.

  Next, in S302, it is determined whether or not the number of pixels in the area of the black portion is larger than the reference area. If it is larger than the reference area (S302: YES), the process proceeds to S303, and if it is not larger than the reference area (S302: NO), the process proceeds to S304. The reason for determining only the image of the water droplet larger than the reference area in this way is that when the image of the water droplet is small, an error becomes large when calculating the roundness in pixel units.

  When there are a plurality of water drop images in the image in the determination of S302, it is determined whether or not the area of the black portion of each water drop image is larger than the reference area, and only the water drop image that satisfies the reference is determined. The process from S304 is executed.

  In S303, it is determined that there was no water repellent effect. The process of S303 is the same as S106 of the first embodiment. After S303, the process ends.

  Next, in S304, the contour length of the black portion is calculated, and the process proceeds to S305.

  Subsequently, in S305, (area) / (contour length) is calculated as the roundness, and the process proceeds to S306. Since the contour length is shorter as it is closer to a perfect circle, the roundness becomes larger as it is closer to a perfect circle. If the areas are different, correction is performed.

  In addition, when there are a plurality of water droplet images in the image, the roundness is calculated for each water droplet, and an average value of S306 or less may be determined.

  In S306, it is determined whether or not the roundness of the black portion is greater than or equal to the threshold value A. If it is greater than or equal to the threshold A (S306: YES), the process proceeds to S307, and if not greater than or equal to the threshold A (S306: NO), the process proceeds to S308. Here, the thresholds A to C are predetermined values for determining the roundness according to the area, and the thresholds A to C are stored in the form of a table. The magnitude relationship between the thresholds A to C is threshold A> threshold B> threshold C.

  In S307, it is determined that the current water repellent effect level is A, and the process proceeds to S309. There are three levels of the water repellent effect, A to C, and the level A is in a state closest to a perfect circle, and the level of the water repellent effect is high. Level A, level B, and level C are in descending order of the water repellent effect.

  Next, in S309, the current absolute time is acquired from the navigation ECU 6, and the area, roundness, and water repellency level are transmitted to the diagnosis ECU 4, stored in the data storage unit 5, and the process proceeds to S310.

  The processing of S310 is the same as S102 and S105 of the first embodiment, and it is determined that there is a water repellent effect, and data that notifies the wiper control device 2 via the data bus 8 is transmitted. After S310, the process ends.

  On the other hand, in S308, it is determined whether or not the roundness of the black portion is greater than or equal to the threshold value B. If it is equal to or greater than the threshold B (S308: YES), the process proceeds to S311. If it is not equal to or greater than the threshold B (S308: NO), the process proceeds to S312.

  In S311, it is determined that the current water repellent effect level is B, and the process proceeds to S313.

  The next processing of S313 is the same as S309. It progresses to S310 after S313.

  In S312, it is determined whether or not the roundness of the black portion is greater than or equal to the threshold value C. If it is greater than or equal to the threshold C (S312: YES), the process proceeds to S314, and if not greater than or equal to the threshold C (S312: NO), the process proceeds to S315.

  In S314, it is determined that the current water repellent effect level is C, and the process proceeds to S316.

  The process of S316 is the same as S309. It progresses to S310 after S316.

  In S315, the current absolute time is acquired from the navigation ECU 6, and zero is transmitted to the diagnosis ECU 4 as the area and roundness values, stored in the data storage unit 5, and the process proceeds to S303. In this case, it is determined that there was no water repellent effect.

  According to the second embodiment, since the roundness is stored together with the date and time, for example, it is verified how long the water repellent effect lasts from the relationship between the passage of date and time and the decrease in the water repellent effect. Or predicting when new water-repellent processing is required.

Here, S309, S313, S315, and S316 executed by the data control unit 9 correspond to storage means.
[Third Embodiment]
Next, a wiper control system according to a third embodiment will be described.

  The wiper control system of the third embodiment is different from the first embodiment only in the process executed by the data control unit 9. Therefore, this difference will be described, and the description of the common points with the first embodiment will be omitted.

  FIG. 11 is a flowchart showing processing executed by the data control unit 9 as the third embodiment. This process differs from the flowchart of FIG. 3 shown as the first embodiment only in the process of S401, and the other processes are the same.

  In S401, the image of the windshield 11 is acquired from the camera 15, and it is the same as S101 in that it is determined whether or not the black portion corresponding to the water droplet image in the image is close to a perfect circle. (S401: NO), the process proceeds to S406, and if close to a perfect circle (S401: YES), the process proceeds to S403. The processes of S403 to S406 correspond to S103 to S106 of the first embodiment, respectively, and are the same process.

  According to the third embodiment, when the image of the water droplet is close to a circle, the movement of the water droplet is further determined, and only when both conditions are satisfied, it is determined that there is water repellent processing. become.

Therefore, according to the third embodiment, it can be determined more reliably that the water repellent effect has occurred.
[Other forms]
As mentioned above, although embodiment of this invention was described, it cannot be overemphasized that this invention can take a various form.

  In each of the above-described embodiments, the data control unit 9 and the wiper control device 2 correspond to the water repellent effect determination device of the present invention. This may be executed by one electronic control unit, or may be distributed to other ECUs.

  In the above embodiment, the wiper control is executed only by determining whether or not the water repellent effect is generated from the roundness and the movement of the water droplets. However, this may be expressed as a numerical value of the degree of the water repellent effect. Alternatively, as exemplified in the third embodiment, the determination may be made at three or more levels.

  At this time, as a method of determining the degree of the water repellent effect from the movement of the water droplet, for example, it is detected how much it has moved upward with respect to the horizontal axis, and the detected angle is close to 90 degrees. In other words, it can be determined that the water repellent effect is more prominent as it moves right up.

  As for roundness, for example, the ratio of the lengths of the major axis and the minor axis may be used assuming that the black portion has an elliptical shape. It may be determined how much there is an error from the perfect circle by matching with the true circle. The roundness may be expressed numerically, but can be replaced with a binary or higher symbol.

1 is a block diagram illustrating an overall configuration of a wiper control system as a first embodiment. It is explanatory drawing which shows the internal structure etc. of a rain sensor. It is a flowchart which the data control part of the rain sensor as 1st Embodiment performs. It is explanatory drawing which shows the internal structure of a rain sensor. It is explanatory drawing which shows the procedure which processes the image which image | photographed the image of the water droplet. It is explanatory drawing which shows the image which image | photographed the image of the water droplet. It is explanatory drawing which shows the process of detecting the motion of the water droplet with progress of time. It is a flowchart which shows the process performed by the wiper control apparatus. It is explanatory drawing which shows an intermittent time about control of the wiping operation | movement of a wiper. It is a flowchart which the data control part of the rain sensor as 2nd Embodiment performs. It is a flowchart which the data control part of the rain sensor as 3rd Embodiment performs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rain sensor, 2 ... Wiper control apparatus, 3 ... Wiper, 4 ... Diag ECU, 5 ... Data storage part, 6 ... Navi ECU, 7 ... Vehicle speed sensor, 8 ... Data bus, 9 ... Data control part, 10 ... GPS Receiving unit, 11 ... windshield, 12 ... infrared LED, 13 ... condensing lens, 14 ... imaging lens, 15 ... camera

Claims (8)

Obtaining an image obtained by irradiating infrared light from the vehicle interior side so as to be totally reflected on the surface of the windshield of the host vehicle, and capturing an image of water droplets attached to the windshield irradiated with the infrared light Means,
Detecting means for converting the image acquired by the acquisition means into an image viewed from the front, and detecting the roundness of the image of the water droplet from the converted image;
A water repellent effect judging device comprising: a judging means for judging that the degree of water repellent effect is larger as the image of the water droplet is closer to a perfect circle based on the roundness detected by the detecting means. The detection means, when there are a plurality of water drop images in the image acquired by the acquisition means, sets the roundness average of the plurality of water drop images to be detected by the detection means. water repellency determination apparatus according to claim 1 Symbol mounting, characterized in that. The detection means detects the roundness of the image of the water droplet as a numerical value,
Water repellency determination apparatus according to claim 1 or claim 2, wherein further comprising a storage means for storing in an internal storage device together with the date the roundness detected by said detecting means. The acquisition means acquires a plurality of images obtained by taking an image of a water droplet attached to a windshield of a traveling vehicle with time.
The determination means is acquired by the acquisition means when the first determination that the degree of water repellent effect is greater as the water drop image is closer to a perfect circle and the traveling speed of the host vehicle is equal to or greater than a predetermined value. claim for detecting the movement of water droplets over time from a plurality of images, the motion of the water droplets and performing a second determination determines that the degree of water repellency as the upward direction is large and The water repellent effect determination device according to any one of claims 1 to 3 . The determination unit is configured to determine the presence or absence of a water repellent effect . In the second determination, when there are a plurality of water droplet images in the image acquired by the acquisition unit, the plurality of water droplets are detected. 5. The water repellent effect determination apparatus according to claim 4, wherein if any one of them moves upward, it is determined that there is a water repellent effect. The control means for reducing the number of wiping operations per unit time of the wiper for wiping off the water droplets on the windshield as the degree of the water repellent effect determined by the determining means increases. The water repellent effect determination device according to any one of claims 5 to 5 . Obtaining an image obtained by irradiating infrared light from the vehicle interior side so as to be totally reflected on the surface of the windshield of the host vehicle, and capturing an image of water droplets attached to the windshield irradiated with the infrared light Means,
Detecting means for converting the image acquired by the acquisition means into an image viewed from the front, and detecting the roundness of the image of the water droplet from the converted image;
A water repellent effect determination apparatus, characterized in that, based on the roundness detected by the detection means, the computer functions as a determination means for determining that the degree of the water repellent effect is greater as the image of the water drop is closer to a perfect circle. Program. Obtaining an image obtained by irradiating infrared light from the vehicle interior side so as to be totally reflected on the surface of the windshield of the host vehicle, and capturing an image of water droplets attached to the windshield irradiated with the infrared light Steps,
Converting the image acquired in the acquisition step into an image viewed from the front, and detecting the roundness of the image of the water droplet from the converted image; and
A water repellent effect determination method comprising: a perfect circle determination step for determining that the degree of water repellent effect is greater as the water droplet image is closer to a perfect circle based on the roundness detected in the detection step .