JP3405302B2 - Image distortion correction device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image distortion correction device, and more particularly to an image signal processing device for correcting image distortion and the like due to lens distortion of a camera.

[0002]

2. Description of the Related Art When an image is captured using an imaging camera,
The image is distorted according to the distortion of the lens system of the camera. Therefore, in order to reduce such image distortion, the input signals picked up by the camera are sequentially stored in the memory for one screen, and each pixel on the screen is moved to reduce the effect of lens distortion. After the correction, the corrected signal for one screen was output. This makes it possible to eliminate the influence of the distortion of the lens system.

[0003]

However, since all the input signals for one screen are once written in the memory and then the pixels are moved, there is a problem that it takes a long time for correction. There is also a problem that a large-capacity memory for storing all input signals for one screen is required.
Furthermore, the lens center of the imaging camera is the reference position of the imaging surface,
For example, if it is deviated from the center, it is necessary to change the amount of movement of each pixel on the screen according to the deviation, and it is extremely difficult to correct the image distortion. The present invention has been made in order to solve such a problem, and uses a small-capacity memory in a short time, and even if the lens center of the imaging camera is deviated from the reference position of the imaging surface, the lens is easily It is an object of the present invention to provide an image distortion correction device capable of correcting image distortion and the like due to distortion.

[0004]

According to a first aspect of the present invention, there is provided an image distortion correction device, in which an image signal is captured by an image pickup camera having a large number of pixels, and the pixels are moved to distort the image due to lens distortion of the camera. In the device that corrects
A memory for storing the image signal taken in by the image pickup camera, a map ROM for storing the required movement amount of pixels for each address of the output image as a map, and an image signal for a screen consisting of a plurality of lines is sequentially taken in by the image pickup camera. And an arithmetic unit for reading out an image signal corresponding to each address of the output image from the memory and sequentially outputting the image signal in accordance with the required movement amount of the pixel stored in the map ROM. The map ROM is used by shifting each address of the output image according to the amount of displacement of the lens center with respect to the reference position of the image pickup surface.

According to a second aspect of the present invention, in the image distortion correcting apparatus according to the first aspect, the map ROM stores in advance the required movement amount of pixels in a region wider than the output image.

In the image distortion correction device according to the first aspect, the image signals of the screen consisting of a plurality of lines are sequentially taken into the memory via the image pickup camera, and the amount of positional deviation of the lens center from the reference position of the image pickup surface of the image pickup camera is obtained. Accordingly, by using the map ROM by shifting the respective addresses of the output image, the image signals corresponding to the respective addresses of the output image are read from the memory according to the required movement amount of each pixel and are sequentially output. Therefore, even if the position of the lens center with respect to the reference position of the image pickup surface of the image pickup camera is deviated due to individual difference of the image pickup camera, the map RO is rewritten without rewriting the map ROM.
By reading the required movement amount of each pixel from M, the image signal corresponding to each address of the output image can be read from the memory. In addition, instead of moving all pixels after writing one screen of the image signal in the memory, an image corresponding to each address of the output image according to the required movement amount of each pixel from the image signal written in the memory. Since the signal is read and output, the time required to correct the image distortion can be shortened and the memory capacity can be reduced.

In the image distortion correction device according to the second aspect, the required movement amount of the pixel in the area wider than the output image is previously set to the map R.
Stored in OM. Therefore, when the map ROM is used by shifting each address of the output image according to the amount of displacement of the lens center with respect to the reference position of the image pickup surface of the image pickup camera, the loss of the data in the map ROM due to the shift is prevented. be able to.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows the configuration of an image distortion correction device according to an embodiment of the present invention. The controller 2 is connected to the imaging camera 1, and the display 3 is connected to the controller 2. The controller 2 is the camera 1
An A / D converter 4 connected to the A / D converter, an arithmetic unit 5 connected to the A / D converter 4, and a D / A converter 6 connected between the arithmetic unit 5 and the display 3. is doing. Further, the controller 2 is provided with a memory 7 and a ROM 8 connected to the arithmetic unit 5. Memory 7 is camera 1
It is for storing the image signal taken in by. Further, the ROM 8 stores in advance, as a map, the necessary movement amount of the pixel for each address of the output image for correcting the image distortion due to the lens distortion of the camera 1. As shown in FIG. 2, the required movement amount of the pixels of the map area 10 wider than the use area 9 of the map data corresponding to the output image is stored in the ROM 8 in advance.

Next, the operation of the image distortion correction device according to this embodiment will be described. Note that, as shown in FIG. 2, the influence of lens distortion of the camera 1 becomes more significant toward the peripheral portion of the screen, so that the amount of pixel movement necessary for lens distortion correction also increases. As shown in FIG. 3, when the lens center O1 of the camera 1 and the reference position (center) O2 of the image pickup surface 11 match, as shown in FIG.
The use area 9 is set at the center of the map area 10 of 8.
The coordinates of the point P0 at the upper left corner of the use area 9 in the map area 10 at this time are (x0, y0).

The image signal of the line at the upper end of the screen is sequentially taken in by the camera 1, A / D converted by the A / D converter 4, and then written in the memory 7 via the arithmetic unit 5. Next, the image signal of the second line from the upper end of the screen is captured, and similarly, the image signals of the lower line are sequentially captured and written in the memory 7.

The arithmetic unit 5 determines the required movement amount of each pixel in the up, down, left and right directions for correcting the distortion of the image due to the lens distortion of the camera 1 (the lower side is +, the upper side is −) within the use area 9 of the ROM 8. Read from the map data of. At this time, since the coordinates of the point P0 at the upper left corner of the usage area 9 in the map area 10 is (x0, y0), the output image 1 shown in FIG.
The ROM 8 is used by shifting each address of the output image 12 so that the origin O (0,0) of 2 becomes the point P0. R
An image signal corresponding to the upper line of the output image 12 is read from the memory 7 according to the movement amount read from the OM 8, is sequentially D / A converted by the D / A converter 6, and is output to the display 3. Similarly, the image signal corresponding to the second line from the upper end of the output image 12 is read from the memory 7 and output according to the movement amount of each pixel. In this way, the image signals corresponding to the lines below the output image 12 are sequentially read from the memory 7 and output.

In this way, the image signals are sequentially fetched from the upper line to the lower line of the screen and written in the memory 7, and the image signals corresponding to the respective lines of the output image 12 are generated in accordance with the moving amount of each pixel. The data is sequentially read from the memory 7 and output to the display 3. When the writing of the image signal of the line at the lower end of the screen is completed, the image signal of the line at the upper end of the screen is captured again in a cyclic manner. Similarly, when the output of the image signal of the lower end line of the output image 12 is completed,
The image signal corresponding to the upper line of the output image 12 is read again from the memory 7 and is output in a cyclic manner.

Here, as shown in FIG. 5, the camera 1
Of the lens center O1 is the reference position (center) O2 of the imaging surface 11.
In contrast, when there are deviations Δx and Δy, the influence of the lens distortion of the camera 1 appears around the lens center O1 of the camera 1, so that the use area 9 is formed at the center of the map area 10 as shown in FIG. If you set, you cannot correct the image distortion due to lens distortion. Therefore, as shown in FIG.
The use area 13 is set at a position displaced by -Δx and -Δy from the center of As a result, the coordinates of the point P1 at the upper left corner of the use area 13 becomes (x0-Δx, y0-Δy), so that the origin O (0, 0) of the output image 12 is output at this point P1. The ROM 8 is used by shifting each address of the image 12.

Since the output image 12 is output in order from the origin O, if the address of the point P1 on the ROM 8 corresponding to the origin O is recognized, the output start position is determined, and the rest of the ROM 8 is determined. It suffices to read the required movement amount of the pixels in order.

Except for the setting of the use area 13 of the ROM 8, the corrected image signals are sequentially processed in the same manner as in the case where the lens center O1 of the camera 1 coincides with the reference position (center) O2 of the image pickup surface 11. It is output to the display 3. By doing so, even if the lens center O1 of the camera 1 is displaced from the reference position O2 of the imaging surface 11, the image distortion can be corrected using the same ROM 8 without rewriting the ROM 8. It will be possible.

The deviation of the lens center O1 of the camera 1 from the reference position of the image pickup surface 11 can be easily measured. Further, the adjustment of this deviation is performed at the time of assembling the camera assembly, that is, at the time of manufacturing. Also, ROM8
The map area 10 therein is set to be wider in advance in consideration of the shift of the lens center O1 of the camera 1 with respect to the reference position of the image pickup surface 11, so that when the ROM 8 is used by shifting each address of the output image. Moreover, the loss of the data in the ROM 8 is prevented.

The image distortion correction device according to the present invention can be applied not only to the non-interlace display method generally used in computers and the like but also to the interlace display method used in televisions and the like. .

[0018]

As described above, according to the first aspect of the present invention, the image signal of the screen consisting of a plurality of lines is sequentially fetched by the image pickup camera and written in the memory, and the lens center with respect to the reference position of the image pickup surface of the image pickup camera. By using the map ROM by shifting each address of the output image according to the amount of positional deviation of the image, the image signal corresponding to each address of the output image is read from the memory according to the required movement amount of each pixel and sequentially output. Since it was done, it is not necessary to write all the input signals for one screen to the memory unlike the conventional case,
It is possible to correct the image distortion and the like due to the lens distortion in a short time and reduce the memory capacity. Even if the lens center of the image pickup camera is deviated from the reference position of the image pickup surface, the necessary movement amount of each pixel is read from the map ROM without rewriting the map ROM, and an image corresponding to each address of the output image is read. The signal can be read from memory. Therefore, it is possible to easily apply the image distortion correction device commonly to various cameras having different characteristics.

According to the second aspect of the present invention, since the necessary movement amount of the pixels in the area wider than the output image is stored in the map ROM in advance, the amount of positional deviation between the lens center and the reference position of the image pickup surface is determined. Even if the map ROM is used by shifting each address of the output image by using the map ROM, it is possible to prevent the data loss of the map ROM.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an image distortion correction device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a map area and a use area of a ROM when a center of a lens of a camera and a reference position of an image pickup surface match each other.

FIG. 3 is a diagram showing a state in which a lens center of a camera and a reference position of an image pickup surface match each other.

FIG. 4 is a diagram showing an output image.

FIG. 5 is a diagram showing a state where a lens center of the camera is displaced from a reference position of an image pickup surface.

FIG. 6 is a diagram showing a map area and a usage area of a ROM when the lens center of the camera is deviated from the reference position of the imaging surface.

[Explanation of symbols] 1 camera, 2 controller, 3 display, 4
A / D converter, 5 arithmetic unit, 6 D / A converter, 7 memory, 8 ROM, 9,13 use area, 10 map area, 11 imaging plane, 12 output images.

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Claims (2)

(57) [Claims] 1. An apparatus for storing an image signal captured by an imaging camera in a device for capturing an image signal with the imaging camera having a large number of pixels and moving the pixels to correct image distortion due to lens distortion of the camera. Memory, a map ROM that stores the required movement amount of pixels for each address of the output image as a map, and an image capturing camera sequentially captures image signals of a screen made up of a plurality of lines, writes the image signals in the memory, and stores them in the map ROM. An arithmetic unit for reading out an image signal corresponding to each address of the output image from the memory and sequentially outputting the image signal in accordance with the required movement amount of the pixel, and the arithmetic unit.
An image distortion correction device characterized in that the map ROM is used by shifting each address of an output image in accordance with a displacement amount of a lens center with respect to a reference position of an image pickup surface of an image pickup camera. 2. The image distortion correction device according to claim 1, wherein the map ROM stores in advance a necessary movement amount of pixels in a region wider than the output image.