JPH06350973A - Picture processing method - Google Patents

Abstract

PURPOSE:To improve the quality of camera pictures fetched by an interlace system by successively extracting the picture element trains of odd-numbered rows and reconstituting pictures by successively arraying the picture element trains by every two rows. CONSTITUTION:A CPU 11 executes processings by a program stored in a program memory 15. A row index is defined as (i)=1, the picture element train of a second (i)-1 row is fetched through a camera IF 12 and is stored in the address of a first row in the memory area #1 of a frame memory 13. Then, the row index is increased by one, the next picture element train is fetched and stored in the third row of the memory 13, repetition is performed until the row index is 256, and when fetching the picture element train of all the odd-numbered rows is completed, fetching the picture element train of even- numbered rows is started. When picture fetching is ended by the interlace system in such a manner, the picture element train of the odd-numbered rows are successively read and the pictures are reconstituted by successively arraying the respective read picture element train by every two rows. As a result, the quality of the fetched camera pictures can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing method for processing an image acquired by a camera means used for a visual sensor or the like, and more particularly to a method for processing an image captured by an interlace system.

[0002]

2. Description of the Related Art In recent years, image sensing technology using a camera means such as a CCD camera has been widely used for the purpose of automating work in a factory or observing, monitoring, displaying, image communication in various facilities. The method of capturing an image captured by such a camera means is roughly classified into an interlace method and a non-interlace method, and the former interlace method is predominant at present. The interlace method captures an image every other row in the first scanning cycle, and captures an image so that the spaces between the rows are sequentially filled in in the next scanning cycle.

When an image captured by this interlace system is displayed or subjected to image processing as it is, pixel information captured in different scanning periods exists in adjacent rows, which causes the following problems. .

(1) When an object that is moving or vibrating is photographed, a jagged disturbance occurs in the image.

(2) When a blinking illumination light source whose illuminance fluctuates in a short cycle such as a fluorescent lamp is used, a jagged unevenness in image density can occur.

(3) If any of these conditions is met, the local image processing frequently used in the visual sensor system or the like will be disturbed. For example, when edge enhancement processing or image smoothing processing is performed, it is usual to perform processing based on a predetermined algorithm on the grayscale information of several pixels above, below, left and right of one pixel. In this case, of the pixel information targeted for local processing, the information of the pixels belonging to the upper and lower adjacent rows (or one additional row) is different from that originally targeted for local processing. The probability of becoming is higher. Therefore, deterioration of image quality after local processing is unavoidable.

As means for avoiding these problems, conventionally, a method of synchronously controlling a strobe light source and a shutter camera and an image reduction method have been used. However, the method using the strobe light source and the shutter camera has a drawback that the cost burden is large. The image reduction method is, for example, 512 ×
Although 512 pixel information is compressed into 256 × 256 pixel information, there is a problem that the amount of information is reduced in both horizontal and vertical directions.

[0008]

SUMMARY OF THE INVENTION The present invention provides an image processing method which solves the above problems when the interlace method is adopted. Further, from another point of view, the present invention provides an image processing method capable of avoiding the problems that the method using the strobe light source and the shutter camera and the image reduction method in the related art have.

[0009]

According to the invention of the present application, a pixel column forming a distant row of each frame is sequentially extracted from an image of each frame captured in an image processing means by an interlace method, and each extracted. When the image of each frame is taken into the image processing means by the image processing method characterized by sequentially arranging one row of pixel columns as consecutive two rows of pixel columns, or by interlacing, According to the above-mentioned conventional technique, the image processing method is characterized by sequentially arranging one row of pixel rows captured immediately before as successive two rows of pixel rows between each phase of sequentially capturing pixel rows forming a separate row. It is a solution to the problem.

[0010]

The principle of the image processing of the present invention will be described with reference to FIG. 1, taking as an example the case where one frame image is composed of 512 × 512 pixels. In the figure, A is a pixel column that is captured in a first image capturing cycle (generally, an odd-row image capturing cycle; hereinafter simply referred to as a first cycle), and B is a second image capturing cycle (generally, even-row image). Capture cycle (hereinafter referred to simply as the second cycle)), and C is a pixel row for one frame obtained by combining the images captured in the first cycle and the second cycle. It is a representation. This is an image capturing method called the interlace method.

In the present invention, the method (I) for correcting the image captured by the interlace method or (II) for executing the additional writing process in the process of capturing the image is shown in D. An image composed of such pixel rows is obtained.

That is, in the method (I), the odd-numbered row L
2n-1 (n = 1,2,3 ..... 256) pixel rows are sequentially extracted, and the image shown by D in FIG. It will be reconstructed.

In the method (II), when the pixel columns of the odd-numbered rows L2n-1 (n = 1,2,3 ... 256) are sequentially taken in, one row (n = i) The image shown by D in the figure is reconstructed by sequentially arranging two rows of the same pixel by utilizing the bright time of Pi at the time of transition from one to the next row (n = i + 1). It is a thing.

In the above description, the image D is acquired based on the pixel columns forming the odd-numbered rows L2n-1, but the image D is acquired based on the pixel columns forming the even-numbered rows L2n. Needless to say, it is possible to obtain

In the image D obtained by the method according to the present invention, the pixel columns captured in the first period and the pixel columns captured in the second period do not coexist in the upper and lower rows. In addition, the above-described jagged image irregularity or uneven density does not occur in the image. Further, local image processing such as edge enhancement can be performed without any trouble.

[0016]

FIG. 2 is a block diagram of the essential parts showing an example of an image processing system used when implementing the image correction processing method of the present invention. To explain this, 10 is an image processing device, which has a central processing unit (hereinafter referred to as CPU) 11, and to the CPU 11, a camera interface 12 connected to a camera 20 and a camera interface 12 are used. Frame memory 13, image processor 14, CP for storing the image signal captured by
A program memory 15 storing a program for controlling the operation of each part of the image processing system via U11, and a monitor 16 for displaying an image before or after image processing.
A data memory 17 that stores data such as a monitor interface 16 connected to (for example, a monitor CRT) and various setting values, and that is also used as a data temporary storage unit when the CPU 11 executes an operation, is provided with a bus 18 respectively.
Connected through.

The system used in this embodiment has an operation mode corresponding to the correction processing methods (I) and (II) described in the section of the above operation, in addition to the normal interlace operation mode. There is. The program for executing the processing corresponding to each operation mode is the program memory 1
Stored in 5. Hereinafter, an outline of processing by the CPU 11 for obtaining an image for one frame according to each operation mode will be described with reference to each flowchart shown in FIG. Here, it is assumed that one frame is made up of 512 × 512 pixels, and the process of acquiring the final image based on the pixel columns forming the odd-numbered rows L2n-1 (see FIG. 2) will be described.

<Mode I> First, in a state where the row index i is reset to 1 (step S1), the pixel column of the 2i-1th row is taken in through the camera interface 12, and the memory area # 1 of the frame memory 13 ( # 1, # 2 ...
Are stored in the address line of the 2i−1th row (the first row is the first row) in the memory area for one frame, respectively (the same applies hereinafter) (step S2). 1
Confirm that the first scanning cycle for the frame has not been completed (step S
3) After counting up the line index by 1 (step S
4) Returning to step S2, the pixel column for the next alternate row is fetched and stored in the address line of the 2i−1th row (the second row is the third row) of the area # 1 of the frame memory 13.

Hereinafter, in steps S2 to S4, i =
When the fetching of all the odd-numbered pixel columns is completed up to 256, the process proceeds to step S5, the row index i is reset to 1, and the fetching of the even-numbered pixel columns is started. In steps S6 to S8, the pixel columns of the 2i-th row (2nd, 4th, 6th, 510th, 512th rows) are sequentially fetched, and the 2ith row (the 2nd i-th row of the memory area # 1 of the frame memory 13). (2, 4, 6, ..., 510, 512 lines) are sequentially stored, and a pixel column for one frame is stored in the area # 1 of the frame memory 13.

When the image capturing by the interlace method is completed, the row index i is reset again (step S9), and the pixel column of the 2i-1th row in # 1 of the frame memory 13 is read (step S10). In the form of being copied using the image processor 14, the second i-th line (first line is the first line) and the second i-th line (the first line is the second line) of the area # 2 of the frame memory 13. It is stored in the address line of (eye) (step S11).

After that, if steps S10 to S13 are repeated until i = 256, the image for one frame indicated by the symbol D in FIG. 2 is secured in the area # 2 of the frame memory 13 ( Processing for one frame is completed).

<Mode II> First, in a state where the row index i is reset to 1 (step U1), the pixel column of the 2i−1th row is taken into the image processing apparatus through the camera interface 12 and stored in the frame memory 13. The data is stored in the address lines of the (2i−1) th row and the 2ith row (the first row is the first row and the second row) in memory area # 1 (step U2). Writing two lines to this frame memory 13
This is performed by using the image processor 14 for the bright time (returning time; see P1, P3, ... In FIG. 1) that occurs between the pixel capture phases for every other row and causing the CPU 11 to perform high-speed processing. To be done.

After the writing of two lines is completed, it is confirmed that the first scanning cycle has not been completed (step U3), the line index is incremented by 1 (step U4), and the process returns to step U2 and the pixels for the next alternate line are read. The columns are fetched and stored in the address lines of the 2i−1th row and the 2ith row (the second row is the third row and the fourth row) in the memory area # 1 of the frame memory 13 as in the previous case. To do.

After that, if these steps U2 to U4 are repeated up to i = 256, the image for one frame indicated by the symbol D in FIG. 2 is secured in the area # 1 of the frame memory 13. (End of processing for one frame).

As described above, mode I and mode I for obtaining a desired image based on the pixel columns forming the odd-numbered rows L2n-1
Although the processing of I has been described, as described in the section of the description of the operation, the desired image is obtained based on the pixel columns forming the even-numbered rows L2n without making essential changes to the above processing. There is no need to explain in detail what can be done.

That is, in mode I, L2, L4, L6.
.. Repeatedly copying and writing while sequentially extracting L510 and L512 to obtain L2, L2, L4, L4, L6 and L6.
The images arranged in the order of L512 and L512 may be reconstructed. In mode II, L2, L4, L6.
... Latching L510 and L512 at the same time, by repeating writing of two lines using the blanking time,
2, L2, L4, L4, L6, L6 ... L512, L5
You can get images arranged in 12 order.

[0027]

According to the present invention, the problem of the interlace system is solved by the system for correcting the image captured by the interlace system or the system for executing the additional writing process in the process of capturing the image. That is,
In the image acquired by the method according to the present invention, the pixel row captured in the first period and the pixel row captured in the second period do not coexist in the upper and lower rows, and therefore, the above-mentioned image is included in the image. No jagged image irregularity or uneven shading occurs. Further, local image processing such as edge enhancement can be performed without any trouble.

Therefore, it is possible to realize a high-quality image without using a system for synchronously controlling an expensive strobe light source and a shutter camera or an image reduction method involving a significant loss of information amount.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the principle of image processing of the present invention by taking an example of the case where an image of one frame is composed of 512 × 512 pixels.

FIG. 2 is a principal block diagram showing an example of an image processing system used when implementing the image correction processing method of the present invention.

FIG. 3 is a flowchart illustrating an outline of processing in two operation modes for implementing the image processing method according to the present invention.

[Explanation of symbols]

 10 Image Processor 11 Central Processing Unit (CPU) 12 Camera Interface 13 Frame Memory 14 Image Processor 15 Program Memory 16 Monitor Interface 17 Data Memory 18 Bus 20 Camera 30 Monitor L001 to L512 Each Pixel in the 1st to 512th Rows Row

Claims (2)

[Claims] 1. A pixel column forming an alternate row of each frame is sequentially extracted from an image of each frame captured in an image processing means by an interlace method, and each extracted pixel column of one row is compared. An image processing method characterized by arranging successively as pixel columns for two subsequent rows. 2. When the image of each frame is captured in the image processing means by the interlace method, the pixel column for one line captured immediately before is phased between the phases of sequentially capturing the pixel columns forming the alternate rows of each frame. An image processing method characterized by arranging successively as pixel columns for two subsequent rows.