JPH087067B2 - Rear monitoring device for parking - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle garage rearward monitoring device, and more particularly to a vehicle garage rearward monitoring device that is highly responsive and highly reliable.

[Conventional technology]

Conventionally, a distance measuring device using an image sensor is well known, and for example, there is one disclosed in Japanese Patent Publication No. 63-46363. FIG. 5 is a block diagram showing an example thereof. In the figure, the left and right optical systems are arranged with a base line length L apart, and each optical system is composed of lenses 1 and 2 and two-dimensional image sensors 3 and 4 arranged apart from the focal length f thereof. It constitutes a pair of left and right video cameras. An image of the distance measuring object M located at a distance R from the lens surface is formed on the image sensors 3 and 4 by the lenses 1 and 2. The image signals obtained from the image sensors 3 and 4 are A
After being converted into digital signals by the / D converters 5 and 6, they are stored in the memories 7 and 8. The image signals stored in memories 7 and 8 are
Image processing is performed by the CPU 9, and the distance from the own vehicle to the object M is calculated and displayed on the display device 10.

The CPU 9 starts with the image sensors from the memories 7 and 8, respectively.
The image signals a1 and b1 corresponding to the upper left ends of 3 and 4 are read out, and the absolute value of the difference c11 = | a1-b1 | is taken. Next, the pixel signals a2 and b2 located one right from the left end are read out, and the absolute value c12 = | a2-b2 | of the difference is calculated. This operation is sequentially performed for all pixels on the screen, and the calculation results are added together to obtain s1 =
Calculate Σc1i. Next, the pixel signal a1 corresponding to the upper left end of the image sensor 3 and 1 from the upper left end of the image sensor 4
The pixel signal b2 on the right of the two is read, c21 = | a1-b2 | is calculated, and the absolute value of the difference is integrated in the same manner as above.
We get s2 = Σc2i. Hereinafter, regarding the image signal corresponding to the image sensor 4, the integrated value si of the absolute values of the differences between the pixel signals when the pixels are sequentially shifted right by one pixel is obtained, and the minimum value is
If it is sj, it means that the left and right images are shifted by j pixels.
Now, if the pixel pitch is p, the amount of left / right deviation is j × p
Then, the distance to the object M is obtained by triangulation by the following equation (1).

R = (f × L) / (j × p) (1) [Problems to be solved by the invention] However, like the distance measuring device described above, comparison of image signals obtained from the image sensors 3 and 4 is performed. When the above is performed on the entire screen, there is a problem that the response time is poor because the calculation time is too long, and the distance cannot be detected when the rear side of the vehicle is a flat image such as a wall.

The present invention has been made in order to solve such a problem, and an object thereof is to obtain a garage rear monitoring device having a short image processing time and high reliability.

[Means for solving the problem]

The garage parking rear monitoring apparatus according to the present invention is configured by arranging an optical system including an image sensor and a lens for forming an image of a marker installed at a predetermined position in the garage on the image sensor at a predetermined distance. A pair of left and right video cameras, a pair of memories for storing the image signals output from each image sensor, a window setting device for setting a window on either the left or right side of the image signals stored in these memories, and a setting Vehicle position detecting means for calculating the distance and angle to the marker by comparing the left and right image signals with the image signal in the selected window as a reference, and either the left or right image signal and the calculated distance and angle And a display device for displaying.

[Work]

In the present invention, a marker as a target at the time of entering the garage is previously arranged in the garage by a method such as sticking or installing according to the shape of the garage, and the window is displayed so that the driver includes the image of the marker. When is set, since the distance calculation and the angle calculation are performed with the image signal in the window as a reference, the vehicle position information having good responsiveness and high reliability can be obtained.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.
In the drawings, the same numbers indicate the same parts.

FIG. 1 is a block diagram showing the configuration of the embodiment. In the figure, a marker MA as a distance measurement object is set at a predetermined position in a garage and has a predetermined pattern. The image of the marker MA is formed by the lenses 1 and 2 on the image sensors 3 and 4 which are installed with their optical axes aligned with the respective lenses. The image signals output from the image sensors 3 and 4 are converted into digital signals by the A / D converters 5 and 6 at a predetermined sampling period, and then stored in the memories 7 and 8. The image signals stored in the memories 7 and 8 are the CPU 9A and the display device.
10A, the CPU 9A performs image processing and then calculates the distance and angle to the marker MA by triangulation, and the display device 10A displays either the left or right image signal and the distance information and angle information. The driver operates a switch (not shown) of the window setting device 11 while observing the image displayed on the display device 10A to display a portion on the screen, that is, the marker MA.
A window, which will be described in detail later, is set in the area including the image of. In the CPU 9A, image processing is carried out based on the screen signal in the window. Although the window is set to the left image in this embodiment, it may be set to the right image.

FIG. 2 is an explanatory diagram showing a region where left and right image signals are compared based on the reference image signal in the window. Window setting device 1 while the driver looks at display device 10A
An image at a predetermined position (i, j) of the memory 7 corresponding to the reference image [Fig. 2 (A)] in the window 13 set to include the image of the marker MA by operating the above-mentioned switch of 1. The signal (a _{i, j} ) and the window 13R at the same position and the same size as the window 13 in the right image [FIG. 2 (B)] are sequentially shifted pixel by pixel by shifting one pixel by one pixel in the horizontal direction. Window 13R at position (i + k, j)
The CPU 9A obtains the absolute value of the difference between the image signals of each pixel from the image signal (b _{i + k, i} ) of the memory 8 corresponding to the image in the window, and determines the absolute value of the difference between the windows (i = 0 to m, j).
= 0 to n) Ask for. The calculation range is the comparison area 14 shown by the shaded area in FIG. The sum Ck thus obtained
Let Cj be the minimum value of, p be the pixel pitch, L be the base length of the optical system, f be the lens focal length, and R be the inter-vehicle distance to the marker MA. Desired.

Further, if the deviation between the center line 15 of the left image and the center line 16 of the window 13 is the number of pixels n, the angle θ between the left video camera and the marker MA can be obtained by the following equation (2).

θ = tan ⁻¹ (f / (n × p)) (2) FIG. 3 is an explanatory view showing the window updating means. Updating the window means that once the window 13 is set, even if the position of the marker MA on the screen changes, as long as the marker MA is within the visual field displayed on the display device 10A,
This means a function of automatically moving the window 13 following the marker MA so that the vehicle position can be continuously measured. The CPU 9A, as shown in FIG. 3 (A), t = t ₀
At this time, after the distance and the angle are obtained by the above procedure, the image signal ai of the memory 7 corresponding to the reference image in the window 13 at that time is stored in the other memory 12. Next, as shown in FIG. 3 (B), among the image signals of the memory 7 sampled at t = t ₀ + Δt, the image signal aj corresponding to the neighborhood area 17 of the window 13 and other The reference image signal of the memory 12 and the neighboring area 17 are sequentially shifted by one pixel in the same manner as described above, and the total sum of the absolute values of the differences between the pixels is calculated. That is, the area 18 is set as a new window at time t ₀ + Δt. here,
When the minimum value of the calculation result is equal to or greater than the predetermined value, it is considered that the marker MA is not in the neighborhood area 17 and an error is displayed. When it is less than the predetermined value, the image signals are compared as in the case of FIG. . Thus, in this embodiment, the marker on the image is
Even if the position of MA changes, the window 13 can be automatically moved following the marker MA.

FIG. 4 is a diagram showing an example of the display screen. In the present embodiment, not only the above error display, but if the distance to the marker MA is less than or equal to a predetermined value, the color of the characters to be displayed blinks,
Alternatively, it is designed to warn the driver by displaying a danger, such as using color.

In this embodiment, the image sensors 3, 4 are shown in FIG.
Although separate sensors are used for the left and right sides, the area of one sensor may be divided and used.

Further, in the display device 10A of this embodiment, a function may be added to inform the driver of the danger by sounding an alarm buzzer during error display or danger display.

〔The invention's effect〕

As described above, the present invention is configured by arranging the optical system including the image sensor and the lens for forming the image of the marker installed at the predetermined position in the garage on the image sensor at a predetermined distance. A pair of left and right video cameras, a pair of memories for storing image signals output from each image sensor, a window setting device for setting a window on either the left or right side of the image signals stored in these memories, Vehicle position detecting means for calculating the distance and angle to the marker by comparing the left and right image signals with the image signal in the window as a reference, and displaying either the left or right image signal and the calculated distance and angle Since it is equipped with a display device that operates, the image signal in the window set by the driver while looking at the display device is displayed. Since the quasi-image signal, compares the process while confirming the reliability of the images for each sampling period,
The calculation time is shorter and the reliability is higher than that of comparing all screens. Further, since the window is automatically updated following the movement of the marker, the distance and angle to the marker can be measured as long as the marker is within the visual field of the display device.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.
FIG. 2 is an explanatory diagram shown in a region where left and right image signals are compared based on a reference image signal in a window, FIG. 3 is an explanatory diagram showing a window updating procedure, and FIG. 4 is an example of a display screen. FIG. 5 is a block diagram of an inter-vehicle distance detecting device using a conventional image sensor. In the figure, MA: marker, 1,2: lens, 3,4: image sensor, 7,8: memory, 9A: CPU, 10A: display device, 11: window setting device, 12: other memory, 13,18 : Window, 1
4: right image comparison area, 17: window 13 neighborhood area. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] 1. A pair of left and right videos configured by arranging an optical system including an image sensor and a lens for forming an image of a marker installed at a predetermined position in a garage on the image sensor at a predetermined distance. A camera, a pair of memories that store the image signals output from each image sensor, a window setting device that sets a window on either the left or right of the image signals stored in these memories, and the images in the set windows Vehicle position detection means for calculating the distance and angle to the marker by comparing the left and right image signals with the signal as a reference,
A display device for displaying either the left or right image signal and the calculated distance and angle is provided, and the driver operates the window setting device to set the window so as to include the image of the marker. A rear monitoring device for entering a garage, characterized in that distance information and angle information between the host vehicle and the marker can be obtained. 2. A window is updated by comparing another memory for storing an image signal in a set window with a reference image signal in the window and an image signal in the vicinity of the window obtained after a predetermined time. Window updating means, and image determination means for determining that the window image has suddenly changed and displaying an error on the display device when the calculation result compared by the window updating means exceeds a predetermined value. The rear monitoring device for garage insertion according to claim 1, characterized in that.