JPH0443911A - Vehicle-to-vehicle distance detector - Google Patents

Abstract

PURPOSE:To stably detect the distance to a targeted precedent vehicle even when there are plural precedent vehicles by detecting the deviation of an upper and a lower corresponding image signal from an image signal in a window as a reference signal. CONSTITUTION:A microcomputer 10 reads a picture element signal in the window 14 where a precedent vehicle image 5a is tracked, out of a memory 9 and uses it the reference image signal for vehicle-to-vehicle distance arithmetic. Then the microcomputer 10 selects an area corresponding to the window 14 on a memory 8 stored with the image signal of a lower image sensor 3 and while the image signal of the memory 8 is shifted to the reference picture element signal by one picture element at each time, the absolute values of differences of signals of upper and lower picture elements are summed up. Consequently, the distance to the precedent vehicle 5 is found. Thus, even if the precedent vehicle 5 which is set once moves to the right or left, the vehicle distance can be obtained continuously.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical distance detection device using an image sensor, particularly an inter-vehicle distance detection device that continuously measures the inter-vehicle distance between a preceding vehicle and the host vehicle. It is related to.

[Prior Art] Conventionally, optical distance detection devices using an image sensor are disclosed in, for example, Japanese Patent Publication No. 38085/1985 and Japanese Patent Publication No. 63-38085.
It is disclosed in Publication No. 46363 and the like. Each of these devices has two optical system lenses 1 on the left and right as shown in Figure 7.
．． 2, and the left and right lenses 1 and 2 are spaced apart by the base line length. Focal path Hf of lens 1.2
Separate Inno-4 image sensors 3.4 are provided at the positions of , and the image signals of the image sensors 3.4 are sequentially shifted and electrically superimposed in the signal processing device 20 to find the best match between the two image signals. Shitatoru.

On the other hand, a method for tracking an image of a preceding vehicle captured by an image sensor or the like is disclosed in Japanese Patent Publication No. 33352/1983. According to this method, the operator sets a tracking gate (window) surrounding the target to be tracked on the display screen while looking at the display screen, so that the target is image-tracked.

(Problem B to be solved by the invention) Conventional distance detection devices are configured as described above, so they can only measure distances to objects that exist in the optical axis direction of the device. In order to measure the distance to a moving object, such as when measuring the distance between the vehicle and the vehicle in front while driving, it was necessary to move the optical axis of the device in that direction. In addition, since the distance to the object is determined by comparing images captured by a pair of left and right optical systems, when trying to measure the distance between the vehicle in front and the vehicle in front as described above, If another vehicle is driving on the left or right side, there are problems such as the driver not knowing which vehicle the distance between them is being measured.

This invention was made to solve the above-mentioned problems. - Once a target is determined, the distance to the target can be continuously measured even if it is moving as long as it is within the field of view. To provide an inter-vehicle distance detecting device capable of determining which preceding vehicle is the object of measuring the inter-vehicle distance even when a plurality of preceding vehicles are running.

[Means to solve the problem]

The inter-vehicle distance detection device according to the present invention compares the upper and lower image signals formed on the image sensor by a pair of upper and lower optical lenses, electrically detects the deviation between the two images, and uses the principle of triangulation to detect the distance ahead. An inter-vehicle distance detection device for measuring the distance to a preceding vehicle, comprising: a display means for displaying an image of the preceding vehicle captured by an image sensor; and a window surrounding the preceding vehicle image;
An image tracking device that tracks the image of the preceding vehicle using this window, and a calculation means that uses the image signal inside the window as a reference signal to detect the deviation between the upper and lower corresponding image signals and calculates the inter-vehicle distance between the own vehicle and the preceding vehicle. It is characterized by having the following.

[For production]

The inter-vehicle distance detection device according to the present invention is capable of calculating and measuring the inter-vehicle distance to the preceding vehicle using a calculation means by using an image signal within the gap as a reference signal and detecting a shift between upper and lower corresponding image signals. .

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a block diagram of the inter-vehicle distance detecting device according to the present invention. In the figure, I and 2 are lenses that constitute the upper and lower optical systems, and 3.4 is a pair of lenses arranged corresponding to lenses 1.2 and 1.2, respectively. dimensional image sensor, 5 indicates the preceding vehicle to be followed, 6.7 is an analog-to-digital converter, 8.9 is a memory, IO is a microcomputer, 11 displays an image captured by the upper image sensor 4 This display is controlled by a microcomputer 10. Reference numeral 12 denotes a device that forms a window for image tracking and also tracks an image of a preceding vehicle surrounded by the window. 13 is an image tracking instruction switch operated by the driver.

Next, the operation will be explained 9. For example, if an image 5a of a preceding vehicle to be followed appears on the image of the upper image sensor 4 and is displayed on the display 11 as shown in FIG. Then, the relative value 1 between the preceding vehicle 5 and the own vehicle is changed, and the preceding vehicle image 5a moves to a position within the image tracking window 14 previously displayed on the display. As shown in FIG. 3, when the image tracking instruction switch 13 is operated by the driver when the image 5a of the preceding vehicle enters the window 14, the image of the preceding vehicle 5a is then displayed on the screen of the display 11. Even if the vehicle moves, the window 14 moves accordingly, and the image tracking function of the preceding vehicle image 15a by the window 14 is automatically performed. This image tracking function is similar to the conventional device disclosed in Japanese Patent Publication No. 60-33352 or Japanese Patent Publication No. 1-35305.

Next, a method for detecting the inter-vehicle distance between the host vehicle and the preceding vehicle will be explained. First, the microcomputer 10 uses the preceding vehicle image 5.
The pixel signals within the window 14 tracking a are stored in the memory 9.
, and use it as a reference image signal for calculating the inter-vehicle distance. Then, the microcomputer 10 selects an area corresponding to the window 14 in the memory 8 in which the image signal of the lower image sensor 3 is stored, and the image signal of the memory 8 is adjusted to 1 for the reference image signal. The total sum of the absolute values of the signal differences between the upper and lower pixels is calculated while sequentially shifting pixels one by one. In other words, the position of the picture that most closely matches the picture within the window 14 is determined while sequentially shifting one IM pixel at a time. At this time, as shown in FIG. 4, the regions involved in the calculation correspond to the upper and lower regions 15 of the image of the preceding vehicle in the image in the memory 8 with respect to the reference image signal in the window 14. As mentioned above, the upper and lower pixels are compared, and the shift amount of the pixel when the sum of the absolute values of the difference signals is the minimum is n pixels, the pixel pitch is P, the baseline length of the optical system is If the focal length of .2 is f and the distance to the preceding vehicle 5 is R, then R can be found by the following formula.

In this way, even if the preceding vehicle 5 moves left or right with respect to the previously set preceding vehicle, it is possible to track it and continuously obtain the inter-vehicle distance from the own vehicle. and,
As shown in FIG. 5, even if another preceding vehicle image 16 enters the screen while tracking the target preceding vehicle image 5a, the pair of image sensors 3 and 4 are substantially moved up and down as in the present invention. Since the image of the preceding vehicle is not included in the lower image comparison area 15, which is compared with the reference image 14, the position of the image that most closely matches the reference image 14 is stably determined. be able to. On the other hand, as shown in Fig. 6, a pair of image sensors 3.4 are arranged on the left and right! In the conventional method, the image comparison area 17 that is thermally compared with the reference image 1' 4 is the area on the left and right of the target preceding vehicle image, so that the image of the preceding vehicle other than the target is also included. The above reference image 14
There may be two positions of the image that most closely match the two, which is not preferable because it becomes difficult to stably detect the inter-vehicle distance.

〔Effect of the invention〕

As explained above, according to the present invention, there is an image sensor that images a preceding vehicle using a pair of upper and lower lenses, a display unit that displays an image of the preceding vehicle captured by the image sensor, and an image tracking device that tracks the image of the preceding vehicle. Since it is equipped with a window and a calculation means that calculates the inter-vehicle distance between the own vehicle and the preceding vehicle by detecting the deviation between the upper and lower corresponding image signals using the image signal in the window as a reference signal, it is possible to detect the distance between the vehicle and the preceding vehicle. It is possible to stably detect the distance between the vehicle in front of the target and the target vehicle in front even when the vehicle is in front of the target vehicle. Furthermore, since the image of the vehicle in front of the target is displayed, the driver can accurately determine the distance between the vehicle and the vehicle in front of the target vehicle. You can find out which vehicles are in front of you.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of an inter-vehicle distance detection device according to an embodiment of the present invention, Fig. 2 is a display diagram with the image of the preceding vehicle within the window, and Fig. 3 is a diagram showing the image of the preceding vehicle completely within the window. 4 and 5.
The figures are diagrams of each image area to be compared with a reference image within a window, FIG. 6 is an explanatory diagram of a conventional image comparison method, and FIG. 7 is a configuration diagram of a conventional distance detection device. 1.2... Lens, 3.4... Image sensor, 5
... Leading vehicle, 6.7... Analog-to-digital converter, 8.9... Memory, 10... Computer, 11
... Display, 12... Image tracking device, 14.
...wind. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent Masuo Oiwa Figure 2 Figure 7

Claims (1)

[Claims] Inter-vehicle distance system that compares the upper and lower image signals formed on the image sensor by a pair of upper and lower optical lenses, electrically detects the deviation between the two images, and measures the distance to the preceding vehicle using the principle of triangulation. The detection device includes a display means for displaying an image of a preceding vehicle captured by an image sensor, a window surrounding the image of the preceding vehicle, an image tracking device for tracking the image of the preceding vehicle using the window, and an image signal within the window. 1. An inter-vehicle distance detection device, comprising: a calculation means for calculating an inter-vehicle distance between the own vehicle and a preceding vehicle by detecting a shift between upper and lower corresponding image signals using as a reference signal.