KR101746531B1 - Vehicle rain sensor and vehicle wiper driving device - Google Patents

Abstract

An image sensing unit sequentially acquiring images of a windshield of a vehicle in a predetermined cycle and sequentially outputting a difference image obtained by subtracting an image at a first viewpoint and a second viewpoint, And a controller for outputting a signal for operating a wiper of the vehicle, wherein the image sensing unit comprises: a light receiving element; a plurality of differential amplifiers connected to each pixel of the light receiving element, And a wiper drive device for a vehicle including the same.

Description

TECHNICAL FIELD [0001] The present invention relates to a vehicular rain sensor and a vehicle wiper drive apparatus having the same. [0002] VEHICLE RAIN SENSOR AND VEHICLE WIPER DRIVING DEVICE [

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a rain sensor for a vehicle that senses raindrops of a windshield of a vehicle and a wiper drive device for a vehicle that controls the operation of the wiper using the detection result.

In recent years, vehicle automation / intelligent technologies such as driver assistance systems, collision warning systems, and automatic temperature control systems have been rapidly developed. Techniques for controlling the operation of wipers by detecting rain or snowing when driving a vehicle have also been developed. It is one.

Since the amount of raindrops covering the windshield of the vehicle also changes depending on the weather condition or the speed of the vehicle, it is necessary to adjust the operation period or speed of the wipers accordingly. In order to automate such a technique, a rain sensor (Operation cycle, speed, etc.) of the wiper according to the amount of the raindrop sensed by using the wiper.

In general, a light sensor is used in which a signal from a LED or the like is obliquely incident on a windshield, and a light sensor installed on the opposite side detects the light sensor. This is a method using a change in the reflectance when there is a raindrop and a change in the amount of light sensed by the optical sensor. This method has a disadvantage in that a relatively large amount of noise is generated due to the influence of reflected light reflected from the windshield surface, which affects the accuracy and requires a complicated optical system.

 In order to overcome such disadvantages, a method using an image capturing means such as a camera has been proposed, which is a method of detecting the presence or absence of raindrops based on image information taken by a photographing means of a windshield. However, in order to cope with the amount of raindrops changing in real time, there is a problem that the amount of image data to be calculated increases and complicated calculation is required. Therefore, various attempts have been made to solve this problem.

Korean Patent Registration No. 10-0660561 (December 15, 2006) Published Japanese Patent Application No. 10-2012-0106776 (September 26, 2012)

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a rain sensor capable of reducing the amount of data required for calculation and capable of sensing raindrops through simple calculations based on existing technologies.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not intended to limit the invention to the precise forms disclosed. Other objects, which will be apparent to those skilled in the art, It will be possible.

In order to achieve the above object, the present invention provides an image sensing apparatus comprising: an image sensing unit for successively acquiring images of a windshield of a vehicle at a predetermined cycle and successively outputting a difference image obtained by subtracting an image at a first viewpoint and a second viewpoint, And a controller for outputting a signal for operating a wiper of the vehicle on the basis of the difference image output from the light receiving element, wherein the image sensing unit comprises: a light receiving element; And a plurality of differential amplifiers that output a plurality of differential amplifiers.

According to the vehicle rain sensor of the present invention, the light receiving element can be configured to focus the focus on the surface of the windshield.

According to the vehicle rain sensor of the present invention, a wide dynamic range image sensor can be used as the light receiving element.

According to the vehicular rain sensor of the present invention, the differential amplifier may be configured to output a difference value corresponding to a voltage difference between the second time point and the first time point, from an electric signal generated in each pixel.

According to the vehicle rain sensor of the present invention, the controller can generate an output signal based on the number of difference values output from the image sensing unit.

According to the vehicle rain sensor of the present invention, the controller calculates a value obtained by dividing the number of pixels for outputting the difference value by the total number of pixels and stores the value in a separate storage space. If the stored value stored in the storage space is equal to or greater than a predetermined threshold value An output signal can be generated. If the stored value is smaller than the threshold value, the controller may accumulate the accumulated value in the storage space so as to accumulate the calculated value in the next period.

According to another aspect of the present invention, there is provided a vehicle wiper drive apparatus including a vehicle rain sensor, a wiper driver for reciprocating a wiper of the vehicle, and a wiper controller for controlling an operation of the wiper driver in accordance with an output signal of the vehicle rain sensor .

According to the vehicle wiper drive apparatus of the present invention, the vehicle rain sensor may be installed in a dashboard or a room mirror of the vehicle so as to direct the vehicle upward.

According to the vehicle wiper driving apparatus of the present invention, the output signal of the vehicle rain sensor is outputted in the form of a pulsed wave, and the wiper controller operates the wiper driver to reciprocate the wiper a predetermined number of times per pulse .

In the present invention having the above-described configuration, a differential image between successively acquired images is used for raindrop detection, and since this differential image does not include an image other than a detection target (i.e., rain, snow, foreign matter, etc.) The amount of data required can be reduced.

In addition, the detection result of the amount of raindrops can be obtained by simple calculation using such small-sized data.

Further, since the differential amplifier is applied to the image sensing unit of the rain sensor, the difference image can be obtained only by the circuit configuration without the processing of the controller, thereby reducing the calculation load of the controller.

In addition, in the conventional method, a complicated process is required because images other than raindrops are included in the image acquisition. However, by focusing the light receiving sensor of the image sensing unit on the surface of the windshield, the shape of the raindrop can be accurately obtained , There is an advantage that the data on the out-of-focus background image can be easily excluded from the process data.

Further, by using the image sensing unit 100 to which the wide dynamic range correction function is applied, there is an advantage that no separate exposure adjustment is required.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a wiper drive apparatus for a vehicle according to an embodiment of the present invention. FIG.
2 is a sectional view showing an example of the internal structure of a rain sensor for a vehicle according to the present invention.
3 is a view showing an installation position and a form of a rain sensor for a vehicle according to the present invention.
4 is a diagram showing the concept of a differential image related to the present invention;
5 is a photographed image illustrating a differential image related to the present invention.
Fig. 6 is a schematic view schematically showing the configuration of the image sensing unit shown in Fig. 1; Fig.
Fig. 7 is a schematic diagram showing the construction and operation of one of the differential amplifiers of Fig. 5; Fig.
8 is a flowchart showing a vehicle wiper driving method according to an embodiment of the present invention.
FIG. 9 is a view showing one example of an output signal of FIG. 8 and a method of controlling the wiper drive according to the output signal.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a vehicle rain sensor and a wiper driving apparatus for a vehicle having the same according to the present invention will be described in detail with reference to the drawings.

1 is a block diagram showing a wiper driving apparatus for a vehicle according to an embodiment of the present invention.

As shown in FIG. 1, a vehicle wiper driving apparatus according to an embodiment of the present invention includes a vehicle rain sensor 100, a wiper driver 300, and a wiper controller 200.

The vehicle rain sensor 100 senses raindrops of the windshield 10 of the vehicle and outputs a signal for driving the wiper. The wiper 30 (see FIG. 9) is installed in the frame of the vehicle and wipes off raindrops, snow, foreign matter, and the like on the surface of the windshield 10.

The vehicle rain sensor 100 includes an image sensing unit 110 and a controller 120. [

The image sensing unit 110 sequentially acquires the image of the windshield 10 of the vehicle at a predetermined cycle and sequentially outputs a difference image (differential image, differential image) obtained by subtracting the image at the first and second points of time . The configuration of the image sensing unit 110 will be described later in detail.

The controller 120 outputs a signal for operating the wiper 30 of the vehicle based on the differential image output from the image sensing unit.

The wiper driver 300 is a driver for reciprocating the wiper 30, and can be configured by a motor and a power transmission means. The wiper 30 and the wiper driver 300 are well known in the art and their detailed description is omitted.

The wiper controller 200 controls the operation of the wiper driver 300 according to the output signal of the rain sensor 100 for the vehicle, specifically, the output signal of the controller 120. The wiper driver 300 operates to change an operation cycle, a speed, and the like of the wiper 30 according to a control signal of the wiper controller 200. The wiper controller 200 may have a configuration separate from the vehicle main controller for controlling the operation of the electronic components of the vehicle, and the function may be included in the vehicle main controller.

 FIG. 2 is a sectional view showing an internal structure of a rain sensor for a vehicle according to the present invention, and FIG. 3 is a view showing an installation position and a shape of a rain sensor for a vehicle according to the present invention.

2, a vehicle rain sensor 100 includes a housing 101 for receiving an image sensing unit 110, a controller 120, and the like. A circuit board 102 on which electronic elements such as an image sensing unit 110 and a controller 120 are mounted is installed in the housing 101 and a condenser lens 103 is mounted on an opening of the housing 101, And the light receiving portion of the light source 100 may be installed.

3 (a), the vehicle rain sensor 100 can be installed on the dashboard 10 of the vehicle so that the light receiving portion thereof is oriented in the upper direction of the vehicle. This is to obtain a more accurate differential image by reducing the influence of the headlight light of the opposite vehicle or the image change due to the driving of the vehicle. The influence of sunlight, road illumination, etc. can be compensated by applying a wide dynamic range function to the image sensing unit 100. Further, since the focus is on the windshield 10, the background image is not clear and it is easy to distinguish it from a sensing material such as a raindrop.

Although not shown in the drawings, it is also possible to install the rain sensor 100 for a vehicle in the dummy board 10 as well as the room mirror. In such a case, the light sensor may be oriented in the upward direction.

On the other hand, it is also possible to dispose the rain sensor 100 such that the light receiving portion of the rain sensor 100 for a vehicle is oriented in a direction inclined at an angle with respect to the horizontal direction (or vertical direction) .

4 is a diagram showing the concept of a difference image related to the present invention.

One rectangle in Fig. 4 represents a pixel, which illustrates an image frame having nine (3 x 3) pixels.

The image sensing unit 110 sequentially acquires images in a predetermined cycle, and this cycle is arbitrarily settable. For example, it is possible to set to sequentially acquire one image frame per second.

4 illustrates an image F1 at a first time point and an image F2 at a second time point after one cycle, respectively. According to this, it is exemplified that a change occurs in one pixel when compared with the image F2 at the second time point and the image F1 at the first time point.

The image sensing unit 110 outputs a difference image F2-F1 obtained by subtracting the image F1 at the first time point and the image F2 at the second time point. According to Fig. 4, only the pixel in which the pixel data has changed remains in the difference image F2-F1, and the pixel in which the change has not occurred is not displayed in the difference image F2-F1. That is, the data related to the pixels that have not changed are removed in the differential processing, and the amount of data transferred from the image sensing unit 110 to the controller 120 can be reduced accordingly.

5 is a photograph image illustrating a difference image related to the present invention.

FIG. 5 is a diagram showing an example in which the image sensing unit 110 calculates the difference between the image F1 actually photographed at the first time point, the image F2 actually photographed at the second time point of the next cycle and the image of the first and second time points, Image F2-F1. The photographed image indicates that the foreign object has been added at the second time point, and it can be confirmed that the remaining portion (background building) excluding the portion where the change has occurred in the difference image F2-F1 is removed as described above.

The image sensing unit 110 sequentially outputs the differential image as described above. That is, the image sensing unit 110 includes first, second, third, fourth, ... Sequentially obtain differential images F2-F1, F3-F2, F4-F3, ... between the respective viewpoints by successively acquiring images F1, F2, F3, F4,

Fig. 6 is a schematic diagram schematically showing the configuration of the image sensing unit shown in Fig. 1, and Fig. 7 is a schematic diagram showing the configuration and operation of one of the differential amplifiers of Fig.

6, the image sensing unit 110 includes a light receiving element 111 and a plurality of differential amplifiers 112 connected thereto.

The light receiving element 111 is an electric element that receives light and converts the image of the windshield 30 into an electric signal and is used as an element such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal-Oxide Semiconductor) . As the light receiving element 111, an image sensor having a wide dynamic range function may be used. This makes it possible to improve the robustness against environmental changes such as nighttime or strong light incidence.

The light receiving element 111 is configured to focus the focus on the surface of the windshield 10. Accordingly, the shape of the raindrop on the surface of the windshield 10 can be accurately obtained, and the data on the background image deviated from the focus can be easily excluded from the processed data.

The differential amplifier 112 is connected to each pixel of the light receiving element 110, specifically, the photodiode PD of each pixel, and each differential amplifier 112 outputs an output value of the electric signal (for example, Value). For reference, FIG. 6 illustrates a light receiving device 111 having nine (3 × 3) pixels, and illustrates a configuration including nine differential amplifiers 112 of the same number.

Referring to FIG. 7, an electric signal at a first time point of the pixel is input to one input terminal of the differential amplifier 112, and an electric signal at a second time point of the pixel is input to the other input terminal. The difference value between the output values of the electric signals at the second time point and the first time point, for example, the difference value corresponding to the voltage difference, is outputted at the output terminal of the differential amplifier 112. [ The signals output from the output terminals of the differential amplifiers 112 are combined to obtain a differential image.

8 is a flowchart illustrating a vehicle wiper driving method according to an embodiment of the present invention.

Referring to FIG. 8, the image sensing unit 110 sequentially acquires the image F1 of the first viewpoint and the image F2 of the second viewpoint S11 and S12. The difference image (F2-F1) obtained by subtracting the image at the first and second points is outputted (S20).

The controller 120 may generate an output signal based on the number of differential values output from the image sensing unit 110. [

Specifically, the controller 120 calculates a value obtained by dividing the number of pixels for which the difference value is output by the total number of pixels (S30). The calculated values are stored in a separate storage space (for example, storage means such as a memory) (S40).

Next, the controller 120 compares the stored value stored in the storage space with a predetermined threshold (S50). As a result, if the storage value stored in the storage space is equal to or greater than a preset threshold value (for example, 30%), an output signal is generated (S60). That is, when the changed area of the entire light receiving area is equal to or larger than a predetermined ratio, it is determined that the raindrop covers the entire area of the windshield 10 at a predetermined ratio or more, thereby generating a signal for operating the wiper 30.

The controller 120 accumulates the stored value in the storage space so that the stored value is cumulatively added to the calculated value in the next cycle if the stored value of the comparison result of the stored value and the threshold is smaller than the threshold value (S70). In this case, the accumulated values accumulated in the storage space are cumulatively added and updated until the value exceeds the threshold value. The controller 120 generates an output signal when the cumulatively accumulated value becomes equal to or greater than a threshold value.

FIG. 9 is a diagram illustrating an example of a form of the output signal of FIG. 8 and a wiper drive control method according to the present invention.

As shown in Fig. 9, the output signal of the rain sensor 100 for a vehicle may be output in a pulsed wave form. FIG. 9A shows the case where the rain is low, and FIG. 9B shows the case where the rain is heavy.

9 (a), the controller 120 of the rain sensor 100 for a vehicle generates a pulse signal only when the cumulative accumulated value becomes equal to or greater than the threshold value, and when the ratio is low, And the cycle is relatively long.

The wiper controller 200 may operate the wiper driver 300 to reciprocate the wiper 30 a predetermined number of times per pulse. 9 shows that the wiper 30 is reciprocated once per pulse. The wiper 30 reciprocates once every accumulated cumulative stored value exceeds the threshold value.

In the case of a large amount of rain as shown in FIG. 9 (b), there may occur a case where the computed value of each obtained differential image becomes equal to or larger than a threshold value. In this case, an output signal is generated every acquisition period of the differential image. This case is the minimum operation period of the wiper 30, and the wiper 30 most frequently reciprocates.

By applying the method of controlling the number of operations or the cycle of the wiper 30 according to the number of the output pulse signals, it is possible to automatically control the wiper operation according to the amount of rain through simple control logic.

The above-described vehicle rain sensor and the wiper drive apparatus for a vehicle having the same are not limited to the configuration and the method of the embodiments described above, but various modifications can be made by those skilled in the art within the scope of the technical idea of the present invention.

10: Windshield 20: Dashboard
30: Wiper 100: Rain sensor for vehicle
110: Image sensing unit 111: Light receiving element
112: differential amplifier 120: controller
200: Wiper controller 300: Wiper driver

Claims (10)

An image sensing unit sequentially acquiring images of a windshield of a vehicle at predetermined periods and sequentially outputting a difference image obtained by subtracting the images at the first and second points of time; And
And a controller for outputting a signal for operating a wiper of the vehicle based on the differential image output from the image sensing unit,
The image sensing unit includes:
Receiving element; And
And a plurality of differential amplifiers connected to each pixel of the light receiving element and outputting a difference value of an output value for each pixel,
Wherein the differential amplifier outputs a difference value corresponding to a voltage difference between the second point and the first point, from the electric signal generated in each pixel,
Wherein the controller generates an output signal based on the number of difference values output from the image sensing unit. The method according to claim 1,
Wherein the light receiving element is configured to focus the focus on the surface of the windshield. The method according to claim 1,
Wherein the light receiving element is a wide dynamic range image sensor. delete delete 2. The apparatus of claim 1,
Wherein a value obtained by dividing the number of pixels in which the difference value is output by the total number of pixels is calculated and stored in a separate storage space and an output signal is generated when the stored value stored in the storage space is equal to or greater than a preset threshold value. . 7. The apparatus of claim 6,
If the stored value is smaller than the threshold value, accumulates the accumulated value in the storage space so as to be cumulatively added to the calculated value of the next period. A vehicular rain sensor according to claim 1;
A wiper driver for reciprocating the wiper of the vehicle; And
And a wiper controller for controlling an operation of the wiper driver in accordance with an output signal of the vehicle rain sensor. 9. The method of claim 8,
Wherein the vehicle rain sensor is installed on a dashboard or a room mirror of the vehicle so as to be directed in an upper direction of the vehicle. 9. The method of claim 8,
The output signal of the vehicle rain sensor is output in the form of a pulse wave,
Wherein the wiper controller operates the wiper driver to reciprocate the wiper a predetermined number of times per pulse.

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