JPH0652312A - Moving body detecting method - Google Patents

Abstract

PURPOSE:To provide the moving body detecting method for calculating informa tion concerning a moving body from the image of difference between the odd- number field image and even-number field image of one frame image. CONSTITUTION:Based on a synchronizing signal, a multiplexer 6 respectively separates an odd-number field image signal and an even-number field image signal from a frame image signal, and the odd-number field image signal and the even-number field image signal are respectively stored in odd-number-field and even-number-field image memories 7 and 8. Those image signals are operationally processed by an operation processing circuit 9, the differential image is provided, and the moving body or a moving amount is detected from this differential image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a moving body detecting method for obtaining information about a moving body by extracting a striped portion generated in the image of a frame by the movement of the moving body by difference processing between an odd field image and an even field image.

[0002]

2. Description of the Related Art Conventionally, when detecting a moving body such as a vehicle,
To detect a moving object by finding the difference between frame images obtained by shooting a predetermined area with one TV camera, or to find the difference between images taken by two high-speed shutter cameras Either method of detecting is adopted.

[0003]

Generally, a television camera samples 30 images per second and converts them into video signals. One frame image is shown in FIG.
As shown in (b), it is composed of an odd-numbered field image and an even-numbered field image taken at a cycle of 1/60 seconds, and corresponds to the interlacing operation of the receiver.

When a moving object moving at a high speed is photographed by a television camera, if an odd field image and an even field image are combined into one frame image, the front and rear of the moving object are
As shown in FIG. 3 (c), blurring (a striped portion A ₁ where the vehicle and the road surface appear alternately) occurs. Therefore, when the moving body is detected by obtaining the difference between the frame images, the moving body must be detected in the frame images in which blurring (hereinafter, referred to as a striped portion) occurs. There is a drawback that accurate detection cannot be performed.

In addition, the method of detecting a moving object using a high-speed shutter camera in order to eliminate this striped portion has a drawback that an underexposure is likely to occur and a strobe is required to prevent the underexposure, The disadvantage is that the body detection device is very expensive.

The present invention has been made in view of the above, and is a movement for detecting a moving body by extracting a striped portion caused by the moving body in one frame image by the difference between the odd field image and the even field image. The object is to provide a body detection method.

[0007]

According to the method of detecting a moving object of the present invention, an image signal of one frame is separated into an odd field image signal and an even field image signal, and a difference between the odd field image signal and the even field image signal is detected. The moving object or the moving amount is detected from the image signal.

[0008]

The moving body detecting method of the present invention eliminates the striped portion caused by the movement of the moving body generated in one frame image.
The moving object is detected by extracting the difference image signal from the odd field image signal and the even field image signal compressed in the moving direction of the moving object, and the moving object is detected by image processing of one frame image. It is a simple moving object detection method that can detect.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the moving body detecting method according to the present invention will be described below with reference to FIG. In Figure 1,
Reference numeral 1 is a television camera, 2 is a low-pass filter that removes noise of high frequency components and prevents aliasing noise during sampling, 3 is an AD converter that converts a video signal into a digital image signal, and 4 is a synchronization from the video signal A sync signal separation processing circuit for separating signals, 5 is an odd / even field detection circuit, 6 is a multiplexer for separating a digital image signal into an odd field image signal and an even field image signal, 7 is an odd field image memory, and 8 is An even field image memory, 9 is an arithmetic processing circuit for performing difference processing, 10 is an image memory in which an image signal subjected to difference processing is stored, and 11 is a moving body detection circuit for detecting a moving body such as a vehicle.

The video signal obtained from the television camera 1 is
It is supplied to the AD converter 3 via the low-pass filter 2, converted into a digital image signal according to the brightness level, and input to the sync signal separation processing circuit 4. The sync signal separation processing circuit 4 separates the horizontal sync signal and the vertical sync signal from the video signal and supplies them to the odd / even field detection circuit 5. In the odd / even field detection circuit 5, an odd / even field is detected based on the synchronization signal, an ON signal is supplied to the multiplexer 6 when the odd field is detected, and an OFF signal is supplied to the multiplexer 6 when the even field is detected. It

The multiplexer 6 is supplied with a digital image signal from the AD converter 3 and an on / off signal corresponding to the sync signal from the odd / even field detection circuit 5. The multiplexer 6 separates the digital image signal into an odd field image signal and an even field image signal. The odd field image signal and the even field image signal are sequentially read into the odd field image memory 7 and the even field image memory 8 without skipping. The respective image signals stored in the odd field image memory 7 and the even field image memory 8 are
When the input of the image signal to the even field image memory 8 is completed, it is read out by the arithmetic processing circuit 9 and the difference processing is performed. The differential image signal obtained from the arithmetic processing circuit 9 is stored in the image memory 10. The image signal read from the image memory 10 is input to the moving body detection circuit 11 to obtain information regarding the moving body.

Next, the difference image processing and the moving body detection will be described in detail with reference to the vehicle image of FIG. The digital image signal obtained from the AD converter 3 is separated into an odd field image signal and an even field image signal by the multiplexer 6, and sequentially distributed to the odd field image memory 7 and the even field image memory 8 and stored. The field images stored in the odd field image memory 7 and the even field image memory 8 are shown in FIG.
As shown in (a) and (b), they are stored in the image memories 7 and 8 in a non-interlaced state. Figure 2
(A) and (b) are field images compressed in the Y-axis direction corresponding to the traveling direction, and the difference image thereof is shown in FIG. 2 (c). In addition, FIG.
The density value on the line L in (c) is shown.

In the arithmetic processing circuit 9, as shown in FIGS.
The odd-numbered and even-numbered field image signals are subjected to difference processing. Matching of pixel signals corresponding to the same address of each field image is detected. By subtracting the pixel signals from each other, the overlapping portion of the vehicle is removed, and the portion D ₁ or D ₂ corresponding to the striped portions before and after the vehicle remains as a difference image. This difference image signal is read into the image memory 10.

In the moving body detection circuit 11, the image memory 10
The differential image signal stored in is read and input.
The difference in the Y-axis direction address value of the portion D ₁ or D ₂ corresponding to the moving amount (| Y ₁₁ -Y ₁₂ | or | Y ₂₁ -Y ₂₂ |) by determining the can detect mobile At the same time, the movement width can be detected. This difference image contains 1/6
Since only the portions D ₁ and D ₂ that have moved in 0 seconds remain, the widths of the portions D ₁ and D ₂ are detected and compared with the distance on the screen measured in advance to double the value. By doing so, the moving distance can be detected.
Also, the moving distance and the equivalent shutter speed (1/60 second)
The speed of the moving body can be detected by.

Of course, in the above embodiment, the odd and even field image memories are provided, but the image signal of one frame is temporarily stored in the frame memory, and the image signals of the odd and even lines are alternately read out and stored. It is obvious that difference processing between lines may be performed.

In the moving object detection method of the present invention, the difference processing between the odd-numbered field image and the even-numbered field image is performed by the arithmetic processing circuit 9 that performs signal processing such as subtraction processing. It can also be formed by a logic circuit or an arithmetic circuit. Further, it can be easily performed by a microcomputer or a processor dedicated to image processing.

Of course, it is obvious that the odd / even field image memories 7 and 8, the image memory 10, and the moving body detection circuit 11 can be easily formed by signal processing by a microcomputer or the like. Further, the moving body detection circuit 11 can obtain the moving body by various methods such as addition processing in the vehicle width direction of the difference image of FIG. 2C and processing with a predetermined threshold value.

[0018]

According to the moving object detecting method of the present invention, the difference between the odd field image signal and the even field image signal separated from one frame image of one television camera
It is possible to obtain information about a moving body such as a vehicle and to detect the amount of movement. The detection accuracy is higher than in the conventional difference processing between frames, and the vehicle speed is determined by using two TV cameras. It is a simple moving object detection method that does not need to be detected.

Further, according to the moving object detecting method of the present invention, since it is not necessary to detect a moving object using an expensive camera such as a high-speed shutter camera, it is not necessary to install a strobe, and one moving object is used. Since the moving object can be detected by the television camera, it is possible to provide an inexpensive moving object detecting device.

Furthermore, since the speed of a moving body such as a vehicle can be detected from only one frame image, image processing is performed at extremely high speed, which is an effective method for determining the vehicle and detecting the moving speed. .

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a moving body detection method according to the present invention.

FIG. 2 is a diagram for explaining the image processing of FIG.
(A) is an odd field image, (b) is an even field image, (c) is a difference image, and (d) is a diagram showing a density distribution.

3A and 3B are diagrams for explaining an image configuration of one frame by an interlaced scanning method. FIG. 3A is an odd field image, FIG. 3B is an even field image, and FIG. 3C is a frame image.

[Explanation of symbols]

 1 TV camera 2 Low pass filter 3 AD converter 4 Sync signal separation processing circuit 5 Odd / even field detection circuit 6 Multiplexer 7 Odd field image memory 8 Even field image memory 9 Arithmetic processing circuit 10 Image memory 11 Moving object detection circuit

Claims (1)

[Claims] 1. A method of separating an image signal of one frame into an odd field image signal and an even field image signal, and detecting a moving body or a moving amount from a difference image signal between the odd field image signal and the even field image signal. A characteristic moving object detection method.