JP2970168B2 - Vehicle detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle detecting device for use in a road traffic system for measuring the position, number, speed, etc. of vehicles running on a road.

[0002]

2. Description of the Related Art In recent years, a vehicle detection device to which image processing technology is applied has been developed and operated. This device detects the vehicle body during the day and the headlights of the vehicle at night,
It was recognized as a vehicle. This detection is performed by performing frame difference processing on the captured image.

[0003]

However, the above-described vehicle detection device has a problem that the headlights of the vehicle are reflected on the road surface at night, especially in rainy weather, and it is difficult to distinguish the vehicle from the vehicle. FIGS. 7A and 7B show a vehicle detection algorithm in which headlight detection is performed without performing lens control. When the frame difference processing is performed on the video signal of the television camera device that images the traveling vehicle, not only the headlight portion of the vehicle with high brightness but also the road surface reflection portion of the headlight is detected, and the headlight light is detected. It is difficult to detect only the portion.

The present invention solves such a conventional problem, and provides a vehicle detection device that can obtain high vehicle detection accuracy without being affected by road surface reflection of headlights even in rainy weather at night. That is.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, the control unit controls the road surface luminance.
Adjust the iris of the TV lens to the desired level.
By recognizing the surrounding illuminance conditions,
In this case, the aperture of the television camera is further adjusted in accordance with the condition .

[0006]

[0007]

According to the first aspect of the present invention, the surrounding environment is set at night.
If it is recognized, the aperture of the TV camera lens
The vehicle head through the lens control voltage generator
The aperture has been narrowed down to the optimum aperture for shooting light.
Because, only it can be reliably extracted headlight.
It is possible to prevent erroneous detection due to road surface reflected light generated in rainy weather .

[0008]

[0009]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an image processing detection device according to the present invention.

In FIG. 1, reference numeral 11 denotes a television camera device for capturing an image of a vehicle;
A lens control voltage generation unit for generating a voltage for controlling one lens, an AD conversion unit for AD-converting a video signal, and a current-converted image data and the A / D converted one frame before and stored in a frame memory A frame difference circuit for executing a difference process with the stored image data, 16
Was made significant by frame differences (ie there was a difference)
A profile circuit that counts the number of pixels in the vertical and horizontal directions to execute a profile process, 17 is a profile memory that stores a profile value that is a calculation result of the profile circuit 16, and 18 stores image data from the AD converter 14. A frame memory 19 determines a vehicle based on the result of the profile memory 17 and calculates a measured amount, and also processes a data of the frame memory 18 to control a diaphragm of the lens 20 of the television camera device 11 (hereinafter, a “CPU”). ) Section.

FIG. 2 is a diagram illustrating an algorithm for detecting a vehicle, in which data in a profile memory is illustrated. The sum of the difference pixels in the horizontal direction is a frame difference horizontal profile 22, and the sum of the difference pixels in the vertical direction is a frame difference vertical profile 23. Since the frame difference process is a subtraction process between the currently captured image data and the image data captured one frame before, a portion of the moving object having a large change in luminance is extracted. That is, the horizontal line component of the vehicle is detected as a horizontal profile value, and the vertical line component is detected as a vertical profile value. Also, dark areas such as shadows and windshields are detected as black components, and bright areas such as bumpers are detected as white components.

Next, the operation of the above embodiment will be described.
The television camera device 11 operates in synchronization with the synchronization signal generated by the synchronization signal generation unit 12, and is a television camera that can operate with an arbitrary number of effective scanning lines. The captured image is converted into 8-bit data 25 by the AD conversion unit 14.
The data is converted into six-gradation digital data, stored in the frame memory 18, and sent to the frame difference circuit 15. The frame difference circuit performs a subtraction process from the previously stored frame data, and extracts a pixel having a significant difference in the current data. The current data is stored as frame data as needed. The extracted significant pixels are added by the profile circuit 16 in the horizontal and vertical directions of the screen, and the number of significant pixels is calculated. FIG. 2 schematically illustrates this state. When a vehicle is present, a characteristic signal of the vehicle is detected. The profile data is stored in the profile memory 17 and the CP
The U unit 19 processes this and measures necessary amounts such as the position and speed of the vehicle. The CPU unit 19 processes the frame memory 18 to measure the road surface luminance, performs a process of selecting a parameter suitable for the road surface luminance, and controls the lens of the television camera device 11. The signal for driving the lens 20 is generated by the lens control voltage generator 13.

FIG. 3 shows the relationship between road surface luminance and lens aperture control. When the road surface luminance increases and becomes equal to or higher than the close threshold, that is, within the closed area, the CPU unit 19 sends a lens aperture close command to the lens control voltage generation unit 13 to generate a lens aperture close signal. On the other hand, when the road surface brightness decreases and falls below the open threshold, that is, within the open area, the CPU 19 sends a lens aperture open command to the lens control voltage generator 13 to generate a lens aperture open signal. Thus, the CPU 19 controls the lens 20 so that the road surface luminance is maintained in the road surface level holding area.

When the road surface brightness reaches a certain value, CP
The U unit 19 determines that it is nighttime, controls the aperture of the lens of the television camera device 11, and removes weak light due to road surface reflection of the headlight to an appropriate aperture value that can extract only the headlight of the vehicle. Set.

FIG. 4 is a diagram showing a headlight detection algorithm when the lens control according to the present invention is performed.
(A) is an original image taken by the television camera device 11,
(B) is a frame difference image when the frame difference processing is performed. Since the vehicle is imaged with the lens set to an appropriate aperture value, when the frame difference processing is executed, only the portion of the headlight light of the vehicle with high luminance is detected, and the road surface reflection of the headlight with relatively low luminance causes The weak light parts are removed. When the headlight section is detected based on the frame difference, the CPU section 19 determines the vehicle width based on the vertical profile value, confirms that the vehicle is a vehicle, and determines the position of the vehicle based on the horizontal profile value.

As described above, according to the above-described embodiment, a high vehicle detection accuracy can be obtained by image processing, particularly for night vehicles in rainy weather, and the frame difference and profile processing can be easily implemented in hardware. The screen processing can be realized at high speed by executing by a circuit, and there is an advantage that highly accurate vehicle physical information can be detected.

[0017]

[0018]

As described above, according to the above-described embodiment, especially for nighttime vehicles in rainy weather, high vehicle detection accuracy can be obtained by image processing, and the frame difference and profile processing can be easily implemented in hardware. The screen processing can be realized at high speed by executing by a circuit, and there is an advantage that highly accurate vehicle physical information can be detected.

[0020]

As is apparent from the above embodiment, according to the first aspect of the present invention , the control unit controls the lens aperture of the television camera, recognizes the surrounding illuminance condition, and reflects the road surface reflection of the headlight. Since only the headlight light of the vehicle is detected by removing the weak light caused by the vehicle, it is possible to detect the headlight even for a nighttime vehicle in rainy weather , and there is an effect that a high vehicle detection accuracy can be obtained.

According to the second aspect of the present invention, even in the case of rainy weather at night, by measuring the length of the headlight in the vertical direction, it is possible to determine whether the light emitted by the vehicle is reflected by the road surface of the headlight. Since the light is judged and recognized and only the headlight light of the vehicle is extracted, there is an effect that high vehicle detection accuracy can be obtained by image processing for night vehicles in rainy weather.

[Brief description of the drawings]

FIG. 1 is a block diagram of a vehicle detection device according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of a vehicle detection algorithm according to an embodiment of the present invention.

FIG. 3 is a conceptual diagram of a lens control algorithm in an embodiment of the present invention.

FIG. 4A is an original image diagram for explaining a vehicle detection algorithm using headlights according to an embodiment of the present invention. FIG. 4B is a frame difference image diagram of the original image.

FIG. 5A is an original image diagram for explaining a vehicle detection algorithm using a headlight according to another embodiment of the present invention. FIG. 5B is a frame difference image diagram of the original image.

FIG. 6 is a flowchart for implementing the algorithm of FIG. 5;

7A is an original image diagram for explaining a conventional vehicle detection algorithm. FIG. 7B is a frame difference image diagram of the original image.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Television camera apparatus 12 Synchronization signal generation part 13 Lens control voltage generation part 14 AD conversion part 15 Frame difference circuit 16 Profile circuit 17 Profile memory 18 Frame memory 19 CPU part 20 Lens 21 Vehicle 22 Frame difference horizontal profile 23 Frame difference vertical profile

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Claims (1)

(57) [Claims] 1. A capturing the traveling vehicle has a television camera for outputting a video signal, said A vehicle detecting apparatus for detecting a vehicle from a video signal, comprising a control unit, road
The TV lens is adjusted so that the surface luminance is at a predetermined level.
Recognizing the surrounding illumination conditions by adjusting the aperture,
According to the illuminance condition, the aperture of the TV camera is further increased.
A vehicle detection device for adjusting the vehicle speed.