JP2002152718A - Image processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing apparatus that reduces a quantity of image data to be stored in a memory for image processing and obtains a required image. SOLUTION: The image processing apparatus stores pixel data from an image pickup element to a memory and processes the stored pixel data to obtain an image, and is provided with a changeover means that selects storage of pixel data with a high density within a prescribed range of a middle of the image in a vertical direction to the memory or storage of pixel data with a relatively low density in the entire range of the image. The changeover means selects the storage of the pixel data depending on a running speed of a vehicle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus for processing lane markings, vehicles, and the like by processing images of road conditions ahead of the vehicle, which are captured by a video camera mounted at a position of a rearview mirror of a vehicle.

[0002]

2. Description of the Related Art A video camera mounted on a vehicle captures an image of a running environment in front of or behind a vehicle, performs image processing based on the captured data, recognizes a preceding vehicle, a white line, or the like, and performs inter-vehicle distance control and the like. ing. FIG. 1 is an example of an image captured by a video camera. The number of pixels of this image is 480 in the vertical direction and 640 in the horizontal direction, and the number of pixels is 480 ×
640 = 307,200. Since the number of bits is 8 bits per pixel, the number of data is 307,200 × 8 = 2,457,600, which is slightly more than 2M bits.

In order to perform image processing, the data obtained from a video camera is temporarily stored in a memory, and image processing is performed by processing the stored data to obtain necessary information.

[0004]

However, storing such a large amount of data requires a large-capacity memory, which raises the cost of the image processing apparatus. In particular, in the case of a device mounted on a vehicle, it is necessary to have a compact and appropriate price, and for that purpose, it is necessary to reduce the amount of data stored in the memory.

[0005]

In order to solve the above-mentioned problems, an image processing apparatus according to the present invention stores pixel data from an image sensor in a memory and processes the stored pixel data to obtain an image. And storing the pixel data having a high density in a predetermined range in the center in the horizontal direction of the image and the pixel data having a relatively low density in the entire range of the image in the memory.
A switching means for selecting and switching is provided. On the other hand, in the vertical direction of the image, only the necessary part of the pixel data is stored in the memory.

The switching means switches according to the traveling speed of the vehicle. For example, when the vehicle is at or below a predetermined speed, relatively low-density pixel data of the entire range of the image is stored in a memory, and when the vehicle exceeds the predetermined speed, a predetermined value at a horizontal center portion of the image is stored. Switching is performed so that pixel data having a high range density is stored in the memory.

The predetermined range at the center in the horizontal direction of the image changes in the range of 0 to 100% of the horizontal length, and the predetermined range can be continuously changed. Then, the length in the horizontal direction can be linearly and continuously changed from 0 to 100% according to the traveling speed of the vehicle. Further, the image processing apparatus of the present invention includes means for extracting high-density pixel data from a predetermined range at the center in the horizontal direction of the image, extracting relatively low-density pixel data from the remaining range, and storing the pixel data in a memory. Have. Conversely, there is provided a means for extracting relatively low-density pixel data from a predetermined range at the center in the horizontal direction of the image, and extracting high-density pixel data from the remaining range and storing it in the memory. Then, by switching the above two means, images having different density distributions can be obtained.

The image processing apparatus of the present invention divides an image into left and right ranges in the horizontal direction, extracts pixel data having a high density only from one of the ranges, and stores it in a memory. At this time, the left and right ranges can be equally divided. In addition, storage of high-density pixel data from one range in the memory and storage of high-density pixel data from the other range in the memory can be arbitrarily switched.

The image processing apparatus of the present invention sets a predetermined range in the horizontal direction of an image, extracts high-density pixel data from the predetermined range, and extracts relatively low-density pixel data from the remaining range. And store it in memory. The predetermined range can be arbitrarily moved in the horizontal direction of the image.

[0010]

FIG. 2 is a block diagram showing an outline of the configuration of an image processing apparatus according to the present invention. In the figure, reference numeral 1 denotes, for example, a video camera of a room mirror size, and a lens 1
1 and an image sensor 12. An image processing apparatus 2 includes an amplifier 21, an A / D converter 22, a memory interface control circuit 23, a memory 24, and a CPU 25.

In the image processing apparatus 2, a signal from the image pickup device 12 is amplified by an amplifier 21, A / D converted, and stored in a memory 24 via a memory interface control circuit 23. The CPU 25 performs image processing based on the data stored in the memory 24, performs recognition of the preceding vehicle, and performs the following distance control according to the recognition result, or issues an alarm. On the other hand, the CPU 25 instructs the memory interface control circuit 23 which part of the image data sent from the image sensor 12 is to be stored in the memory 24, that is, which area of the screen is to be processed and how. . The memory interface circuit 23 controls which range of data on the screen is stored in the memory 24 based on a command from the CPU 25.

FIG. 3 is a diagram for explaining an embodiment of the present invention. In FIG. 1A, reference numeral 11 denotes a lens of a video camera, and reference numeral 12 denotes an image sensor. In this case, FIG.
As shown in the figure, the image sensor 12 has 1024 elements in the vertical direction and 768 elements in the horizontal direction, and has about 800,000 elements in total. In FIG. 3A, ranges (1) and (2) indicate ranges of pixel data stored in a memory for image processing among pixels captured by the image sensor. For example, when a lens for forming an image in a range of 60 ° on the image sensor is used, the range (1)
Is the range captured with a wide viewing angle of 60 °, and the range (2)
Is the range captured at a narrow viewing angle of 30 °. In the present invention, the viewing angle is changed according to the traveling speed.

When traveling at a low speed, for example, 40 km
In the case of / h or less, a wide viewing angle indicated by the range (1) is set, and a short distance is mainly captured in the field of view, so that when there is an interrupting vehicle, it can be recognized. In this case, of the horizontal pixels 1024, 512 pixels are extracted every other pixel. Also, 240 rows are extracted by interlacing the lower 384 pixels of the vertical pixels from which a required image of a preceding vehicle or the like can be obtained. And 512 × 240 × 8
(Bits) = 983,040 bits of data are stored in the memory and subjected to image processing.

On the other hand, when the vehicle is traveling at a high speed, for example, when the vehicle speed exceeds 40 km / h, a long distance is mainly captured in the visual field as a narrow viewing angle shown in the range (2). In this case, of the pixels 1024 in the horizontal direction, 512 pixels within a 30 ° angle range at the center are extracted without thinning. Therefore, a required image in a predetermined range can be obtained at a high density. As for the pixels in the vertical direction, 240 rows are extracted by interlacing the lower 384 pixels as in the low-speed case. Then, as in the case of low speed, 51
2 × 240 × 8 (bits) = 983,040 bits of data are stored in the memory and subjected to image processing. In addition,
As for the pixels in the vertical direction, only the pixel data of the lower half where the vehicle or the like exists is extracted as described above, but the upper half may be included if necessary, or may be 2/3 from the bottom. . That is, it is only necessary to be able to arbitrarily take out necessary parts. The same applies to the embodiments described below.

The data stored in the memory as described above is
High-density pixel data for a predetermined range of images,
By selecting any of the pixel data for the entire range of the image, which is relatively low in density, only the necessary data can be stored in the memory, thereby reducing the amount of data stored in the memory. In addition, a single video camera can provide the function of a wide-angle lens and the function of a telephoto lens with the same data amount, and can obtain a required field of view at low speed or at high speed. Note that the density of pixel data is relative,
It suffices if the density of the pixel data in the necessary part of the image is increased and the other parts are relatively reduced, so that the pixel data can be used effectively within a limited range.

The wide viewing angle and the narrow viewing angle can be selected according to the traveling speed. However, the wide viewing angle and the narrow viewing angle are set at predetermined time intervals, for example, every one second or every one minute regardless of the traveling speed. By switching the narrow viewing angle, it is possible to capture the short distance and the long distance simultaneously in the field of view. In the above case, the wide viewing angle and the narrow viewing angle are selected and switched according to the traveling speed, but the viewing angle is in the range of 0 ° to 60 °, in other words, in the range of 0 to 100% in the horizontal direction of the image. Can be changed continuously. In addition, as shown in FIG. 4, the viewing angle can be changed linearly and continuously according to the traveling speed. FIG. 4 is a graph showing an example of a change in the viewing angle with respect to the vehicle speed. The horizontal axis is the hourly speed representing the vehicle speed, and the vertical axis represents the viewing angle. In this example, the viewing angle is set to 30 ° when the speed is 40 km / h, and the viewing angle becomes smaller when the speed is higher and the viewing angle becomes larger when the speed is lower.

FIG. 5 is a diagram for explaining another embodiment of the present invention. In the figure, the pixels taken out from the range (2) in the central portion are assumed to have a high density, and the density of the pixels taken out from the range (1) in the periphery is made relatively low. For example, the viewing angle of the range (2) is set to 15 °, and horizontal pixels 256 of this portion are extracted. On the other hand, the remaining range (1)
There are 768 pixels in the horizontal direction in the range of the viewing angle of 45 °. This is the number of remaining pixels obtained by subtracting the number of pixels (256) extracted in the range (2) from the total number of pixels in the horizontal direction (1024).

Of the 768 pixels, one out of three (2
56 pixels) and store them in the memory. On the other hand, as for the pixels in the vertical direction, as described in the above embodiment, the lower half 384 pixels are interlaced to 24 pixels.
Fetch row 0. By taking out the pixels stored in the memory in this manner, the image at the center can be a high-density image and the image at the peripheral portion can be a relatively low-density image.

Also in this case, the number of pixels extracted from the horizontal direction is 512, and the number of pixels extracted from the vertical direction is 24.
0, and the amount of pixel data stored in the memory is the same as in the previous embodiment: 512 × 240 × 8 (bits) = 98
3,040 bits. As described above, by changing the range and density of selecting pixels without increasing the data amount, it is possible to obtain the most necessary image.

FIG. 6 is a view for explaining a modification of the present invention described with reference to FIG. In this modification, the density of the pixels extracted from the central range (2) is low, and the density of the pixels extracted from the peripheral range (1) is high.
The total angle of the viewing angles x1 and x2 in the peripheral range (1) is 15 °, and the viewing angle in the central range (2) is 45 °. Then, 256 horizontal pixels are extracted from the peripheral range (1), and one out of three 768 horizontal pixels in the remaining central portion range (2) are extracted (256 pixels).
Pixel). As for the pixels in the vertical direction, as described in the above description, 240 rows are extracted by interlacing the lower 384 pixels. By taking out the pixels in this way, it is possible to make the peripheral portion a high density image and the central portion a relatively low density image.

Then, it is possible to select and switch between an image having a higher density in the central portion and an image having a higher density in the peripheral portion in accordance with the traveling speed. Further, it is possible to select and switch between an image having a higher density at the center and an image having a higher density at the periphery at predetermined time intervals. Further, it is possible to select and switch between an image with a higher density at the center and an image with a higher density at the periphery according to the inter-vehicle distance to the preceding vehicle. For example, when the inter-vehicle distance is within 30 m, the image is selected so as to obtain an image with a high density at the peripheral portion, and when the inter-vehicle distance exceeds 30 m, the image is selected and switched so as to obtain an image with a high density at the center. Can be. The opposite is also true.

In the above embodiment, the image is divided into two ranges of 45 ° and 15 °. However, the image is not fixed to this angle but can be changed arbitrarily. FIG. 7 is a diagram for explaining another embodiment of the present invention. As shown in (a) of the figure, the viewing angle is 30 ° on each of the right and left sides.
Range (1) and range (2) are provided. And
At a certain point in time, half of the pixels 1024 in the horizontal direction of the image are extracted as high-density pixel data from the right side range (1), and at another point in time, they are extracted from the left side range (2). On the other hand, as for the pixels in the vertical direction, the lower half 384
Interlace the pixels and extract 240 rows. Then, extraction of pixels from the range (1) and extraction of pixels from the range (2) can be arbitrarily switched. For example, one of them can be selected and switched at every preset time, and when the image on the right side of the own vehicle is particularly required, the time for extracting pixels from the range (1) on the right side can be lengthened. In this case, the range (1) is set to 80% and the range (2) is set to 2% as shown in FIG.
0%. In the opposite case, for example, the range (1) is set to 20%
And the range (2) is set to 80%.

In the above-described embodiment, the screen is divided equally into the left and right sides. FIG.
FIG. 4 is a view showing another embodiment of the present invention. In the figure,
The viewing angle is divided into a predetermined range (1) and another range (2) in the horizontal direction of the image, and the density of the pixel data extracted from the range (1) is increased to increase the density of the pixel data extracted from the range (2). Make the density relatively low. Then, the range (1) located on the middle side of the figure is configured to be arbitrarily movable without changing the viewing angle. That is, it is possible to arbitrarily move the screen in the horizontal direction. For example, if an interrupting vehicle enters from the right side, the range (1) is moved to the right, and if there is a vehicle entering from the left side, the range (1) is moved to the left. Explaining the configuration specifically, the number of pixels captured in the range (1) is
For example, 384 pixels 640 (1024) in the range (2)
-384 = 640), four pixels are thinned out, and one of five pixels, that is, data of a total of 128 pixels is captured and stored in the memory. Therefore, also in this case, the number of pixels taken into the memory among the pixels in the horizontal direction is 512. On the other hand, as for the pixels in the vertical direction, as described in the above description, if 240 rows are taken out by interlacing the lower 384 pixels, the amount of data stored in the memory is the same as in the previous embodiment. Becomes

[0024]

According to the present invention, high-density pixel data is extracted from a certain range in an image and stored in a memory, and relatively low-density pixel data is extracted from another range and stored in a memory. Since these can be switched and an image can be obtained, only necessary data can be stored in the memory with emphasis. Therefore, the amount of data stored in the memory can be reduced without deteriorating the quality of the image from the needs. As a result, the amount of memory of the image processing apparatus can be reduced, so that downsizing and cost reduction of the apparatus can be achieved.

[Brief description of the drawings]

FIG. 1 shows an example of an image captured by a video camera.

FIG. 2 is a block diagram illustrating an outline of a configuration of an image processing apparatus according to the present invention.

FIG. 3 is a diagram illustrating an embodiment of the present invention.

FIG. 4 is a diagram illustrating an embodiment of the present invention.

FIG. 5 is a diagram illustrating an embodiment of the present invention.

FIG. 6 is a diagram illustrating an embodiment of the present invention.

FIG. 7 is a diagram illustrating an embodiment of the present invention.

FIG. 8 is a diagram illustrating an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Video camera 11 ... Lens 12 ... Image sensor 2 ... Image recognition device 21 ... Amplifier 22 ... A / D converter 23 ... Memory interface control circuit 24 ... Memory 25 ... CPU

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G06T 1/00 330 G06T 1/00 330B 1/60 450 1/60 450E H04N 5/907 H04N 5/907 B F term (reference) 5B047 AA19 BB04 CB30 EA01 EB06 5B057 AA06 AA16 BA02 CA08 CA12 CA16 CB08 CB12 CB16 CD07 CH11 CH14 CH18 5C052 GA01 GA03 GA07 GB01 GC03 GC05 GD09 GE04 5C054 AA01 EA07 FD07 FE07 GB02

Claims (14)

[Claims] 1. An image processing apparatus for storing pixel data from an image sensor in a memory and processing the stored pixel data to obtain an image, comprising: An image processing apparatus comprising: a switching unit that selectively switches between storing pixel data and pixel data having a relatively low density of an entire range of an image in a memory. 2. The switching means stores relatively low-density pixel data of the entire range of the image in a memory when the vehicle is at or below a predetermined speed, and stores the pixel data when the vehicle exceeds the predetermined speed. 2. The image processing apparatus according to claim 1, wherein switching is performed so that pixel data having a high density in a predetermined range in a central portion in the horizontal direction of the image is stored in the memory. 3. A predetermined range of a central portion in the horizontal direction of the image changes in a range of 0 to 100% of a horizontal length, and the predetermined range is continuously changed. The image processing device according to claim 1, wherein 4. A predetermined range of the center of the image in the horizontal direction is 0 to 1 in the horizontal length according to the traveling speed of the vehicle.
2. The image processing apparatus according to claim 1, wherein the image processing apparatus changes linearly and continuously within a range of 00%. 5. An image processing apparatus for storing pixel data from an image sensor in a memory and processing the stored pixel data to obtain an image, wherein a density of the image is determined from a predetermined range in the center in the horizontal direction of the image. An image processing apparatus comprising: means for extracting high pixel data, extracting pixel data having a relatively low density from the remaining range, and storing the pixel data in a memory. 6. An image processing apparatus which stores pixel data from an image sensor in a memory and processes the stored pixel data to obtain an image, wherein the image processing apparatus is relatively located within a predetermined range of a central portion in the horizontal direction of the image. An image processing apparatus comprising: means for extracting low-density pixel data from the memory, extracting high-density pixel data from the remaining area, and storing the extracted data in a memory. 7. An image processing apparatus for storing pixel data from an image sensor in a memory and processing the stored pixel data to obtain an image, wherein a density of the image is determined from a predetermined range in the center in the horizontal direction of the image. First means for extracting high pixel data and capturing relatively low density pixel data from the remaining range; and extracting relatively low density pixel data from a predetermined range in the horizontal center of the image. And second means for capturing high-density pixel data from the remaining range, and storing the pixel data extracted by the first means and the pixel data extracted by the second means in a memory. An image processing apparatus comprising a switching unit for switching. 8. The image processing apparatus according to claim 1, wherein the switching unit switches according to a traveling speed of the vehicle. 9. An image processing apparatus for storing pixel data from an image sensor in a memory and processing the stored pixel data to obtain an image, wherein the image is divided into left and right ranges in the horizontal direction. An image processing apparatus comprising means for extracting pixel data having a high density only and storing the pixel data in a memory. 10. The image processing apparatus according to claim 9, wherein the right and left ranges are equally divided. 11. A switching means for arbitrarily switching between storage of high-density pixel data from the one range in the memory and storage of high-density pixel data from the other range in the memory. The image processing apparatus according to claim 9, wherein 12. An image processing apparatus which stores pixel data from an image sensor in a memory and processes the stored pixel data to obtain an image, wherein a predetermined range is set in a horizontal direction of the image, and An image processing apparatus comprising: means for extracting high-density pixel data from the range, and extracting relatively low-density pixel data from the remaining area, and storing the pixel data in a memory. 13. The image processing apparatus according to claim 12, wherein the predetermined range is arbitrarily moved in a horizontal direction of the image. 14. The image processing apparatus according to claim 1, wherein only pixel data of a necessary part in a vertical direction of the image is stored in a memory. Image processing device.