JPH11328368A - Image recognizing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the constitution of a field memory and to speed recognizing processing. SOLUTION: The image recognizing device which recognizes an environmental image of a road where vehicles travel is equipped with a CCD(charge coupled device) camera 1 which picks up images of the road, a recognizing processing part 4B which performs processing for recognizing the environmental image of the road according to image data obtained from the CCD camera, an FIFO (first-in first-out) field memory 3 which is positioned between the CCD camera and the recognizing processing part and performs first-in first-out operation when writing image data equivalent to one field from the CCD camera and reading them out to the recognizing processing part so as to adjust the image pickup speed and recognizing processing speed, a synchronizing signal detection part 6 which detects a synchronizing signal from the output of the CCD camera, and a write control part 7 which writes the center part of a picture plane picked up by the CCD camera 1 except the circumferential part by controlling the writing of the image data to the FIFO field memory 3 according to the synchronizing signal of the synchronizing signal detection part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recognition apparatus for recognizing a preceding vehicle based on an image, and more particularly to an apparatus capable of simplifying the configuration of a field memory and accelerating a recognition process.

[0002]

2. Description of the Related Art In the above-mentioned image recognition apparatus, image data obtained by image pickup by a CCD (Charge Coupled Device) camera is processed by a central processing unit (CPU). Are recognized.
CPU rather than data rate output from CCD camera
Since the capturing speed on the side is usually much faster, a field memory is provided as a buffer between the CCD camera side and the CPU side.

An address circuit is provided in this field memory, through which data is written from the CCD camera side and data is read out to the CPU side.

[0004]

By the way, it is an object of the above-mentioned image recognition apparatus to simplify its structure and reduce the cost. However, there is a problem that the address circuit of the field memory complicates the structure of the image recognition device and increases the cost.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image recognizing apparatus which can be simplified in structure, performs a recognizing process quickly, and reduces the cost in view of the above problems.

[0006]

According to the present invention, there is provided an image recognition apparatus for recognizing an environmental image of a road on which a vehicle travels, wherein the CCD camera captures an image of the road, A recognition processing unit that performs processing for recognizing a road environment image based on image data obtained from the CCD camera; and a control unit that is located between the CCD camera and the recognition processing unit and adjusts an imaging speed and a recognition processing speed. A FIFO field memory for writing one field of image data from a CCD camera to perform the reading and a first-in first-out when reading data to a recognition processing unit, and a synchronization signal detection unit for detecting a synchronization signal from the output of the CCD camera And controlling the writing of image data to the FIFO field memory based on the synchronization signal of the synchronization signal detection unit, thereby controlling the CCD camera. To provide an image recognition apparatus characterized by comprising a write control unit for writing the central portion excluding the peripheral portion of the screen to be imaged La.

By this means, a FIFO field memory which performs first-in first-out is used as a field memory, so that an address circuit is not required as in the prior art. The central part from which the part has been removed is written, that is, the part that is not so important for image recognition is not written. For this reason, the processing in the recognition processing unit has been accelerated.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a schematic example of an image recognition device according to the present invention, which uses one CCD camera. As shown in the figure, one CCD camera 1 is mounted in front of the vehicle. An analog-to-digital converter (A / D) 2 connected to the output of the CCD camera 1 converts an image signal of each imaged pixel from analog to digital at the timing of a sampling signal, and converts, for example, an 8-bit density value. And output the pixel data.

The FIFO (first in first out) field memory 3 connected to the A / D converter 2 stores the A / D converter 2
Pixel data is written at the timing output from
The pixel data previously written at the timing of a capture signal of the CPU 4 described later is read first. The output of the capture signal starts at the timing of the vertical synchronizing signal of the CCD camera 1, and ends when the reading is completed. in this way,
Since the FIFO field memory 3 is used as the field memory, the address circuit conventionally used for writing and reading becomes unnecessary, so that the configuration is simplified and the cost can be reduced.

For example, in an image recognizing device 4 composed of an 8-bit CPU, pixel data fetched from the FIFO field memory 3 is stored in a volatile memory (RAM) 4A, and is recognized by a recognition processing unit 4B as described later. Next, the vehicle in front is recognized. The timing generator 5 supplies a sampling signal to the A / D converter 2. The synchronization signal detection unit 6
An output signal of the D camera 1 is branched and input, and a synchronization signal is detected. Note that the vertical signal from the synchronization signal detecting unit 6 is CP
It is output to U4 and used for the output timing of the capture signal.

The write controller 7 receives the synchronization signal from the synchronization signal detector 6 and the sampling signal from the timing generator 5 and outputs a write control signal to the FIFO field memory 3. FIG. 2 is a diagram illustrating an example of an edge image of the rear part of the preceding vehicle recognized by the image recognition device 4. As shown in the figure, the image recognition device 4 extracts edges from data of 640 pixels × 240 pixels (for one field), smoothes them temporally, and blurs an image portion of an object having a large change on a screen. Extract only the part with little change on the screen. In this way, an edge image is extracted for an object such as a vehicle ahead, a white line, a sign, and the like that moves little on the screen. Further, since the number of edges at the rear part of the front vehicle is large, the front vehicle can be recognized from the edge distribution within the white line.

FIG. 3 is a diagram showing a configuration example of the write control unit 7, and FIG. 4 is a diagram for explaining a timing example of the write control unit 7. As shown in FIG. 3, the counter 71 receives the sampling signal from the timing generator 5 and the horizontal synchronization signal from the synchronization signal detector 6, and counts the number of sampling signals at the timing of the horizontal synchronization signal as shown in FIG. Count.

The comparator 7 connected to the output of the counter 71
2 inverts the output when the number of input counts exceeds a. The counter 73 receives the sampling signal from the timing generator 5 and the output signal of the comparator 72, and counts the number of sampling signals at the timing of the output signal of the comparator 72.

The comparator 7 connected to the output of the counter 73
3 inverts the output when the input count number becomes b or more, and outputs the inverted signal to the FIFO field memory 3 as a write control signal. FIG. 5 is a view for explaining an example of image data stored in the FIFO field memory 3. This will be described using the same image data as the preceding vehicle in FIG. 2. As shown in FIG. 2, in the FIFO field memory 3, two left and right a pixels × 240 pixels are displayed on the surrounding screen by a write signal from the write control unit 7. No writing is performed on the portion, and writing is performed on the central portion of b pixels × 240 pixels. Here, 2a + b = 640 pixels.

While the vehicle is traveling straight, the recognition processing unit 4B normally locates the front vehicle at the center of the screen imaged by the CCD camera 1, and the surroundings do not contribute to the recognition of the front vehicle. No data is needed. For this reason, CP
Since the surrounding image data is not processed in U4, the processing speed is increased by adding a simple configuration. When the steering angle of the steering wheel of the vehicle is detected and the vehicle keeps traveling straight for a certain period of time, the CCD is operated as described above.
The left and right sides of the screen imaged by the camera 1 may be deleted to perform the processing of the center.

FIG. 6 is a diagram showing a modification of the configuration of the write control unit 7, and FIG. 7 is a diagram for explaining a timing example of the write control unit 7 in FIG. The circuit configuration in FIG. 6 and the timing in FIG. 7 are almost the same as those in FIGS. 3 and 4, and a horizontal synchronizing signal is used in FIG. 6 instead of the sampling signal in FIG. In No. 6, a vertical synchronizing signal is used.

FIG. 8 shows the write control unit 7 shown in FIG.
FIG. 3 is a diagram illustrating an example of image data stored in an FO field memory 3. As described above, the description will be made using the same image data as that of the preceding vehicle in FIG. 2, as shown in FIG.
In the IFO field memory 3, writing is not performed on the upper and lower two 640 pixels × c pixels by the writing signal of the writing control unit 7, but writing is performed on the central portion of 640 pixels × b pixels. Where 2c + d = 24
0 pixels.

FIG. 9 shows a modification of the configuration of the write control unit 9, which is a combination of the configuration examples of FIG. 3 and FIG. 6, and FIG.
FIG. 3 is a diagram illustrating an example of image data stored in an FO field memory 3. As shown in FIG. 9, an OR circuit 79 is newly provided to combine the configurations of FIGS. As shown in FIG. 10, writing is not performed on the left and right two a pixels × 240 pixel portions and the upper and lower two 640 pixels × c pixel portions by the writing signal of the writing control unit 7, and the b pixel × Writing is performed on the central portion of the d pixel.

FIG. 11 is a diagram showing another example of the outline of the image recognition apparatus of FIG. As shown in the figure, if the CPU constituting the image recognition device 4 is 16 bits instead of 8 bits in FIG. 1, the FIFO field memory 3 is replaced by the odd field FIFO odd field memory 3A and the even field FIFO An even field memory 3B may be provided. A switch 8 is provided on the output side of the A / D converter 2, and a vertical synchronizing signal from the synchronizing signal detecting unit 6
The O odd field memory 3A and the FIFO even field memory 3B are alternately selected.

In this configuration, the same operation and effect as described above can be obtained. Next, an application to an image recognition device that recognizes a preceding vehicle by triangulation using two CCD cameras will be described. The two CCD cameras are arranged at regular intervals and at a constant height in front of the vehicle.
FIG. 12 shows an image recognition device according to the present invention, in which two C
It is a figure showing the example of the outline using the CD camera. As shown in the figure, A / D converters 2-1 and 2-2 connected to respective outputs of CCD cameras 1-1 and 1-2 convert captured image signals from analog to digital at the timing of sampling signals. And outputs, for example, pixel data having an 8-bit density value.

In each of the FIFO field memories 3-1 and 3-2 connected to each of the A / D converters 2-1 and 2-2, the output from each of the A / D converters 2-1 and 2-2 is provided. Pixel data is written at the timing
The pixel data previously written at the timing of the capture signal of No. 4 is read first. Each output of the capture signal starts at the timing of the vertical synchronizing signal of each of the CCD cameras 1-1 and 1-2, and ends when the reading is completed.

For example, in the image recognition device 4 composed of a 16-bit CPU, the FIFO field memories 3-1 and 3 are used.
The pixel data fetched from each of -2 is stored in each of the volatile memories (RAM) 4A-1 and 4A-2, and the recognition processing unit 4B recognizes the preceding vehicle as described later. Each of the synchronization signal detectors 6-1 and 6-2 branches and inputs the output signal of each of the CCD cameras 1-1 and 1-2.
Detect the synchronization signal. Note that the synchronization signal detection units 6-1 and 6
-2 are output to the CPU 4 and used for the output timing of the capture signal.

Each of the write control units 7-1 and 7-2 receives a synchronization signal from each of the synchronization signal detection units 6-1 and 6-2,
A sampling signal is input from the timing generator 5 that supplies a sampling signal to each of the A / D converters 2-1 and 2-2, and a write control signal is output to each of the FIFO field memories 3-1 and 3-2. The configuration is the same as described above.

FIG. 13 is a view for explaining the recognition processing of the preceding vehicle by the recognition processing section 4B of FIG. As shown in the figure, the CCD cameras 1-1 and 1-2 mounted on the vehicle
For convex lenses a and b having a focal length f,
The lenses a and b are each located at a certain height H from the road surface, are separated from each other by a certain distance d, their axes are parallel, the line passing through the lenses a and b is the x-axis, Axis as the y-axis, the position of the lens a as the origin of the xy plane,
Further, an axis perpendicular to the xy plane is defined as a z-axis. The coordinates of the lens a are (0, 0, 0), and the coordinates of the lens b are (0, 0, 0).
d, 0), and the coordinates of the reference point P of the vehicle are (x, y, −
(Hh)). h means the height of the reference point from the road surface. Observation points A and B with respect to the reference point P are located on the observation surface of the lenses a and b on the opposite side of the reference point P with respect to the x-axis and away from the x-axis by the focal length f. The coordinates of the observation point A are (−x _a , −f, z _a ), and the coordinates of the observation point B are (−
x _b, -f, it is a z _b). According to the principle of triangulation, the coordinates of the reference point P (x, y, h) are obtained from the coordinates of the observation point as follows.

X = x _a · d / (x _a− x _b ) y = x _a · f / (x _a− x _b ) h = H−linear aP · sin α = H−Ｈx ² + y ² + (H -h) ^2} therefore ^{1/2 · sinα, h = H -} {(x 2 + y 2) / (1-sin 2 α)} 1/2 sinα = z a / (z a 2 + f 2) 1/2 It is.

In this way, when the reference point P is at a certain height h from the road surface, it is recognized as a vehicle ahead. Various indications are drawn on the road on which the vehicle travels, and further, there are patterns of road distortion and the like. This is because if the display, the pattern, and the like are determined as an image of the vehicle by the image ranging device and the observation point corresponding to the reference point is set, the recognition of the preceding vehicle cannot be obtained.

FIG. 14 shows observation points in the image recognition unit of FIG.
FIG. 4 is a diagram illustrating an example of obtaining A and B. As shown in this figure
Stored in the memories 4A-1 and 4A-2 of the CPU 4.
For example, check the correlation in the area of 4 pixels x 4 pixels.
You. That is, 4 pixels × 4 pixels in the memory 4A-1
Density value A of the pixel in the area₁₁, A₁₂, A₁₃, A₁₄, A_{twenty one},
... A ₄₄Area of 4 × 4 pixels in the memory 4B-1
Pixel density value B₁₁, B₁₂, B₁₃, B₁₄, B_{twenty one}… B₄₄
Then, Δ is obtained as follows.

Δ = | A ₁₁ −B ₁₁ | + | A ₁₂ −B ₁₂ | + | A ₁₃ −B ₁₃ |
_{+ | A 14 -B 14 | +} | A 21 -B 21 | + ... + | A 44 -B 44
| A region of two 4 pixels × 4 pixels where Δ is minimized is an observation point for the reference point. For the observation points obtained in this way, the height of the gauge point is obtained. When the vehicle is traveling straight, the writing control units 7-1 and 7-2 use the observation points with respect to the reference point P at the central portion excluding the periphery of the screen imaged by the CCD cameras 1-1 and 1-2. Is required, so that the processing speeds up.

FIG. 15 is a diagram showing another example of the outline of the image recognition apparatus of FIG. As shown in FIG.
Is 16 bits in FIG.
If it is 2 bits, the FIF
Instead of the O field memory 3-1, an odd field FIFO odd field memory 3A-1 and an even field FIFO even field memory 3A-2 are provided. Also, for the CCD camera 1-2, instead of the FIFO field memory 3-2, an odd field FIFO is used.
O Odd field memory 3B-1 and F of even field
IFO even field memory 3B-2 is provided. A /
A switch 8 is connected to each output side of the D converters 2-1 and 2-2.
1 and 8-2, and the FIFO odd field memories 3A-1 or 3A-2 are alternately selected by the respective vertical synchronization signals of the synchronization signal detectors 6-1 and 6-2.
Odd field memories 3B-1 or 3B-2 are alternately selected. Even in such a configuration, the same operation and effect as described above can be obtained.

[0030]

As described above, according to the present invention, the FIFO memory is provided as the field memory, and the write control is performed so as to prevent the writing of the surrounding unimportant portions. However, the cost can be reduced quickly.

[Brief description of the drawings]

FIG. 1 is an image recognition device according to the present invention, wherein one C
It is a figure showing the example of the outline using the CD camera.

FIG. 2 is a diagram illustrating an example of a rear edge image of a front vehicle recognized by an image recognition device 4;

FIG. 3 is a diagram illustrating a configuration example of a write control unit 7;

FIG. 4 is a diagram illustrating a timing example of a write control unit 7;

FIG. 5 is a diagram illustrating an example of image data stored in a FIFO field memory 3;

FIG. 6 is a diagram showing a modification of the configuration of the write control unit 7;

FIG. 7 is a diagram illustrating a timing example of a write control unit 7 in FIG. 6;

8 is a diagram illustrating an example of image data stored in a FIFO field memory 3 by a write control unit 7 in FIG.

FIG. 9 is a diagram showing a modification of the configuration of the write control unit 9, which is a combination of the configuration examples of FIGS. 3 and 6;

10 is a diagram illustrating an example of image data stored in a FIFO field memory 3 by a write control unit 7 in FIG.

FIG. 11 is a diagram showing another example of the outline of the image recognition device of FIG. 1;

FIG. 12 is a diagram showing a schematic example of an image recognition device according to the present invention, which uses two CCD cameras.

13 is a diagram illustrating a recognition process of a preceding vehicle in a recognition processing unit 4B in FIG.

14 is a diagram illustrating an example of obtaining observation points A and B in the image recognition unit in FIG.

FIG. 15 is a diagram showing another example of the outline of the image recognition device of FIG. 12;

[Explanation of symbols]

1, 1-1, 1-2: CCD camera 2, 2-1, 2-2: A / D converter 3, 3A, 3B, 3, 1, 3-2, 3A-1, 3A-
2, 3B-1, 3B-2 ... FIFO field memory 4 ... image recognition device 4A, 4A-1, 4A-2 ... memory 4B ... recognition processing unit 5 ... timing generation unit 6, 6-1 and 6-2 ... synchronization Signal detection unit 7, 7-1, 7-2 ... write control unit 8, 8-1, 8-2 ... switch

Claims (8)

[Claims] 1. An image recognition device for recognizing an environment image of a road on which a vehicle travels, comprising: a CCD camera for capturing an image of the road; and an environment image of the road based on image data obtained from the CCD camera. And a recognition processing unit for performing processing for writing and recognizing one field of image data from the CCD camera positioned between the CCD camera and the recognition processing unit to adjust the imaging speed and the recognition processing speed. A FIFO field memory for performing first-in first-out when reading out to a processing unit; a synchronization signal detection unit for detecting a synchronization signal from the output of the CCD camera; and a FIFO based on the synchronization signal of the synchronization signal detection unit.
An image recognition apparatus, comprising: a write control unit that controls writing of image data to a field memory to write a central portion excluding a peripheral portion of a screen captured by the CCD camera. 2. The image recognition apparatus according to claim 1, wherein the writing control unit performs writing of a central portion excluding left and right peripheral portions of a screen captured by the CCD camera. 3. The image recognition apparatus according to claim 1, wherein the writing control unit performs writing of a central portion of the screen imaged by the CCD camera excluding upper and lower peripheral portions. 4. The image recognition apparatus according to claim 1, wherein the writing control unit performs writing of a central part of a screen imaged by the CCD camera, excluding left, right, upper, and lower peripheral parts. 5. The image recognition apparatus according to claim 1, wherein said CCD camera comprises one CCD camera, and said recognition processing unit performs a process of obtaining a road environment image from an edge image. 6. The image recognition apparatus according to claim 1, wherein the CCD camera is composed of two CCD cameras, and the recognition processing unit performs a process of obtaining an environmental image of a road based on the principle of triangulation. . 7. The FIFO field memory provided in the CCD camera and the recognition unit includes an odd field memory for storing an odd field, an even field, and an even field output from the CCD. The image recognition device according to claim 5. 8. The writing control unit writes a central portion of a screen captured by the CCD camera excluding a peripheral portion of the screen when the vehicle keeps traveling straight, in the FIFO field memory. The image recognition device according to claim 1, which performs the operation.