JPH04198711A - Distance detecting device - Google Patents

Abstract

PURPOSE:To detect inter-vehicle distances from multiple preceding vehicles by setting multiple windows on one of a pair of photographed images, and comparing the distances from objects captured by the windows with a pair of image signals. CONSTITUTION:The infrared light is radiated to preceding vehicles 5 at a fixed sampling period, images are formed by image sensors 3, 4 and stored in memories 8, 9. A microcomputer 10 displays the images of one memory 9 on a display unit 11 and displays multiple windows via the output signal from a window setting means 12 overlappingly on the images. The microcomputer 10 detects the drift quantity of the image of the corresponding image signal by using the image signals in the windows as reference signals and calculates the distances from the preceding vehicles 5 specified by the windows. Inter-vehicle distances can be detected even when multiple preceding vehicles are running.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical distance detection device using an image sensor, and particularly to a vehicle that measures the distance to an obstacle or a preceding vehicle in front of a running vehicle. The present invention relates to a distance detection device for use.

[Conventional technology]

Conventional distance detection devices include those disclosed in, for example, Japanese Patent Publication No. 63-3805 and Japanese Patent Publication No. 63-46363. They are lenses as a pair of optical systems and are installed separated by the base line length. 3.4 is an image sensor, which is installed at the focal length f of the lens 1.2.

30 is a signal processing device that inputs image signals from the image sensors 3 and 4 and calculates the distance MR to the object 31.

Next, the operation will be explained. The image of object 31 is captured by lens 1
．． 2 onto image sensors 3 and 4. Image signals corresponding to the optical images are output from the image sensors 3 and 4 and input to the signal processing device 30. The signal processing device 30 uses the image signals of one of the image sensors 3 and 4 as a reference and sequentially shifts and electrically superimposes the other image signal, and calculates the amount of shift when the pair of image signals match best! The distance R from to the target object -L 31 is calculated by R=-7 using the principle of triangulation.

In addition, Japanese Patent Publication No. 18122/1983 discloses that when the image contrast of the object image formed on the image sensor is unclear, multiple light emitting lights are used to illuminate the object in order to make the contrast clear. A device is disclosed that includes an element.

[Invention tries to solve! [Jllll] Conventional distance detection devices are configured as described above, so when there are multiple objects within the field of view of the image sensor, there is a problem that it is unclear which object the distance is being measured from. there were. In particular, when a distance detection device is installed in the own vehicle and the distance to the vehicle in front is measured by the distance detection device while driving, another vehicle in front traveling in the adjacent lane comes within the field of view of the image sensor. When approaching, the driver does not know which vehicle in front the distance detection device is detecting.

In addition, when the brightness of outside light is insufficient for distance measurement in a tunnel or at dusk, if the light emitting element is used to illuminate the vehicle in front, the occupants of the vehicle in front will be dazzled by the illumination light, making it particularly difficult for the driver of the vehicle in front to drive. There were issues such as the inability to ensure safety.

This invention was made to solve the above-mentioned problems, and it is possible to image the preceding vehicle and detect the distance H even in a tunnel or at twilight without dazzling the occupants of the preceding vehicle.
A distance detection device that allows you to know which object is being measured even when multiple objects are in the field of view of the image sensor, and can measure each distance to the multiple objects almost simultaneously. The purpose is to obtain.

[Means to solve the problem]

The distance detection device of the present invention is a distance detection device using the principle of triangulation, and includes an image sensor sensitive to infrared rays, a display means for displaying one of a pair of images taken by the image sensor, and a display means for displaying one of a pair of images taken by the image sensor. a window setting means for setting a plurality of windows; a distance calculation means for comparing and processing a reference signal within the window with an image signal of the other image; and calculating a distance of a target captured for each window; It is equipped with infrared irradiation means that irradiates objects with infrared rays.

[For production]

The distance detection device in the Kome invention uses an infrared VAN irradiation means to irradiate an object in front of the own vehicle with infrared rays without dazzling the occupants of a preceding vehicle or an oncoming vehicle when there is little outside light, and the object is surrounded by a window and designated. The principle of triangulation is realized by facilitating the imaging of a target object by an image sensor, and detecting the amount of image shift of the corresponding image signal using each image signal in a plurality of windows as a reference signal using a distance calculation means. Calculates the distance to the object specified in each window.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure shows an example of a case where a distance detection device according to an embodiment of the present invention is mounted on a running vehicle to measure the distance between the vehicle and a preceding vehicle. In FIG. 1, numerals 1 and 2 constitute a pair of optical systems installed vertically apart by a baseline length, and numerals 3 and 4 are lower lenses 1 and 2. An image sensor 5 which is also sensitive to infrared rays and is disposed apart from the focal length f of the lens 1.2 in correspondence with the upper lens 2, and 5 runs in front of the own vehicle in front of the lens 1.2. The object is the preceding vehicle. 6 and 7 are A/D (analog/digital) converters that digitize the image signal from the image sensor 3.4, and 8.9 is the digitized image signal output from the A/D converter 6.7. Memory for storing 1o
is a microcomputer (hereinafter referred to as microcomputer).

11 is a display device for displaying an image captured by the upper image sensor 4 under the control of a microcomputer 10 which receives an image signal from a memory 9; 12 is for specifying the preceding vehicle 5 for distance measurement on the image; This is a window setting device as a window setting means for setting a window. A plurality of windows 13, 14, 15, 16, 17 set by this window setting device 12 are formed in advance on a predetermined portion of the display screen of the display 11, as shown in FIG. 24 is a halogen lamp, and the light emitted from the lamp passes through an infrared filter 25 that transmits only infrared rays, and irradiates the preceding vehicle 5 with infrared rays. and,
The vertical illumination angle (B) illuminated by the halogen lamp 24 is determined by the image sensors 3 and 4 by the lens 1.2.
is smaller than the viewing angle (A) of the plurality of windows 1
It is configured to mainly illuminate a viewing range surrounded by 3.14°15.16.17. The microcomputer 10 uses the image signal within the window set by the window setting device 12 as a reference signal from the memory 9.

a memory 8 corresponding to each of these reference signals;
A distance calculation means is configured to calculate the distance to the object for each window by performing comparison processing while shifting the image signals of each area within the window.

FIG. 3 is an explanatory diagram showing one display west side of the display 11, and FIG. 4 is an explanatory diagram showing images in the memories 8 and 9, windows, and comparison areas thereof.

Next, the operation of one embodiment will be described with reference to FIGS. 1 to 4. The preceding vehicle 5 turns on the halogen lamp 2 depending on the outside light condition.
4 through an infrared filter 25 or not. This image of the preceding vehicle 5 is formed on an image sensor 3.4 via each lens 1.2. The pair of optical images have the same relative positional relationship between the left and right sides, but differ in the relative positional relationship between the upper and lower sides. A pair of image signals output from the image sensor 3.4 are digitized by an A/D converter 6.7 and stored in a memory 8.9.

This operation is performed at a constant sampling period. The microcomputer 10 displays the image captured by the image sensor 4 on the display 11 based on the image signal from the memory 9, and also changes the vertically long windows 13, 14, 15, 16, 17 horizontally based on the output signal from the window setting device 12. Overlay the image in a line.

For example, an image 5a of a preceding vehicle 5 as shown in FIG.
Suppose that is displayed on the display 11.

Then, the microcomputer 10 reads out from the memory 9 an image signal corresponding to the image in the window 15 that captures the preceding vehicle image 5a, and uses it as a reference image signal for calculating the inter-vehicle distance. Then, the microcomputer 1O selects an area corresponding to the window 15 in the area of the memory 8 where the image signal from the lower image sensor 3 is stored.Next, the microcomputer 10 selects the reference image signal within the window 15. The image signals of the selected area in the memory 8 are sequentially shifted one pixel at a time, and the sum of the absolute values of the signal differences for each pixel of the upper and lower images is calculated. That is, the microcomputer 10 uses window 1
The position of the image that most matches the image in 5 is determined by sequentially shifting one pixel at a time from the selected area of the image in memory 8. At this time, as shown in FIG. 4, the areas involved in the calculation are the reference image in the window 15 in the image 9a in the image signal in the memory 9, and the area in the window 15 in the image 8a in the image signal in the memory 8, as shown in FIG. Area 20 corresponding to the position
It is. This area 20 includes the same area relatively as the window 15, has the same width as the window 15, and has a vertical direction of -
This is the part that has been extended into a cup. Therefore, each time the sum of the absolute values of the image signal differences is calculated, the pixel shift is performed in the column of the area 20 (
This is performed sequentially for each pixel, that is, for each row, in the vertical) direction.

As mentioned above, the microcomputer 1O compares the image signals of the upper and lower images, and determines that the image signal in the window 15 and the image signal in the area comparable to the area of the window 15 in the area 20 are in the same relative positional relationship. A pixel shift amount n is determined when the sum of absolute values of differences between certain image signals becomes the minimum. Then, if the pixel pitch of the image sensors 3 and 4 is p, and the distance to the preceding vehicle 5 corresponding to the preceding vehicle image 5a is R, the microcomputer 10 calculates the distance @R according to the following formula il1.

f−L R=□ ・・・
(11n'p In this way, the distance R to the preceding vehicle 5 displayed in the window 15 can be measured.

In the same manner as above, another preceding vehicle traveling in the adjacent lane comes into the field of view of the image sensors 3 and 4 formed by the lens 1.2, and the image 23 of the preceding vehicle is displayed as shown in FIG. Captured by window 17. Then, the microcontroller
O uses the image signal within the window 17 as a reference signal,
By selecting the area 22 of the image in the memory 8 that corresponds to the window 17 of the image 9a in the memory 9, and finding the position of the image that most closely matches the image in the window 17 within this area 22, the amount of deviation between both images is determined. is determined by the number of pixels. Then, the microcomputer 10 calculates the inter-vehicle distance between the other preceding vehicle and the host vehicle using the above equation (11).

The microcomputer 10 displays the distance calculation result on the display 11, for example.
The driver can be notified by displaying the information on the screen corresponding to the window.

In this way, even when a plurality of preceding vehicles are running, the inter-vehicle distance to each preceding vehicle can be known almost simultaneously.

As described above, the object captured by the windows 13, 14, 15, 16, and 17 set within the screen of the display 11 is captured by the area 18 corresponding to each of these windows, as shown in FIG. Images are compared in windows 19, 20, 21, 22, and windows 13, 14, 15, 16 .
The distance to the object can be measured every 17 seconds.

Although the above example shows an example in which five windows are set, the number of windows can be set arbitrarily depending on the size of the object within the field of view of the image sensor using the lens, the number of objects that require distance measurement, etc. .

Furthermore, the size and shape of the window may be changed arbitrarily depending on the size and shape of the object. Of course, it goes without saying.

Furthermore, as an infrared irradiation means] \Rogen Lampf.

The wall showing the combination of 24 and infrared filter 25 may be of any type as long as it can emit visible light or infrared rays excluding most of the visible light, and is not limited to the above embodiments. do not have.

Furthermore, although a pair of lenses and an image sensor are installed on the upper and lower sides, the same effect as in the above embodiment can be obtained even if the lenses and image sensors are installed substantially on the left and right or diagonally.

〔Effect of the invention〕

As described above, according to the present invention, a plurality of windows are set in one of a pair of images captured by an image sensor, and the distance of the object captured by these windows is determined by a pair of windows corresponding to the images in each window. The system is configured to measure based on the principle of triangulation by comparing the image signals of
This has the effect of being able to detect the distance between each vehicle in front.

Furthermore, it is equipped with infrared illumination means to illuminate the vehicle in front captured by multiple windows, and the image sensor has infrared sensitivity, so it can be used in tunnels or at twilight without dazzling the occupants of the vehicle in front. This has the effect of capturing an image of the vehicle in front.

Further, by setting the range to which infrared rays are irradiated to a part of the field of view of the image sensor, there is an effect that the infrared ray irradiating means can be made inexpensive and compact.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a distance detection device according to an embodiment of the present invention, FIG. 2 is a diagram showing a plurality of windows set on the display screen of a display device, and FIG. 3 is a diagram showing an image of a preceding vehicle within the display screen. FIG. 4 is an explanatory diagram showing the images in both memories and the image area to be compared with the reference image in each window. FIG. 5 is an explanatory diagram showing the configuration of a conventional distance detection device. It is a diagram. In the figure, t, 2... Lens, 3.4... Image sensor, 5... Leading vehicle, 8.9... Memory, 10...
Microcomputer, 11...Display device, 12...Window setting device, 13.14, 15, 16.17...Window, 24...Halogen lamp, 25...Infrared filter. Note that the same reference numerals in the figures indicate the same or equivalent parts. Fig. 2 13-I7; Uinto Fig. 3 5 (+, 23: Predecay (-L-I-2) Fig. 4 +3 14 15 16 17 Fig. 5

Claims (1)

[Claims] A pair of optical systems forms a pair of images of the object on an image sensor, the image signals of both images obtained from the image sensor are compared, and the amount of deviation between both images is electrically detected to perform triangulation. A distance detecting device that measures the distance to an object based on the principle of the present invention includes a display means for displaying one of the two images captured by the image sensor, and a window for setting a plurality of windows in a predetermined portion of the one image. By using the setting means and the image signals in each of the set windows as reference signals, and performing comparison processing with the image signal of the other image corresponding to each of these reference signals,
distance calculation means for calculating the distance to the object captured for each window; and infrared irradiation for irradiating infrared rays within the field of view of the image sensor by the pair of optical systems corresponding to the area surrounded by the plurality of windows. and means;
A distance detection device characterized in that the image sensor described above has sensitivity to infrared rays.