JPS5997272A - Storage and restoring method of high resolution picture signal - Google Patents

Abstract

PURPOSE:To prevent the deterioration in picture quality by dividing a high resolution picture signal into a video memories of standard resolution, and storing them. CONSTITUTION:The high resolution picture 10 is divided equally into four to form four screens 12, 14, 16 and 18, each is D/A-converted at a D/A converter to form a signal S1 for one screen's share, which is stored in memories 20, 22. The picture signal at the boundary with an adjacent sub-frame is stored in a memory 30 as a digital signal. The digital picture of each sub-frame is inputted to a histogram processor 26, the luminance distribution is obtained and stored in the memory 30. In the restorating method, the analog information is read out from the memories 20, 22, and converted into digital signals, the luminance distribution of this signal is obtained and the luminance is corrected so as to minimize the difference with the luminance distribution stored in the memory 30. The positioning is attained based on the picture signal of the boundary part read out from the memory 30.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for storing and restoring high resolution image signals in a standard resolution analog video memory such as an NTSC video disc.

Prior Art and Problems High-resolution image signals represent one screen with a larger number of pixels, such as 1024 x 1024 pixels, than the 512 x 512 pixels that can be stored as a digital image signal in a standard NTSC video signal. If you try to store it as is on a video disc using the same system, you will have to divide it into four screens and store one screen, which may result in misalignment at the joint, different brightness levels (because DA/AD conversion is performed), etc. A problem arises. In the conventional method, it is simply 10
D/A 24X 1024 high resolution digital image signals
I convert it, store it on a video disk, and play it back to get a high-resolution digital signal, but when I store it on the video disk, it becomes the standard resolution of 512X512, so I interpolate it to 1024X 1024.
Although this does not cause the problem of positional deviation, the image quality deteriorates and the level of the high resolution signal of the angle of inclination is lowered to a normal resolution signal.

Purpose of the Invention The present invention stores a high-resolution image signal as it is in a standard-definition video memory, but divides it and stores it, so that even when it is played back, the divided portions do not shift in position or shift in brightness level. The aim is to provide a method to do so.

Structure of the Invention The high-resolution image signal of the present invention is obtained by dividing one screen of a high-resolution image into multiple screens of standard-resolution images, and converting the digital image signal of each of the divided screens into an analog signal for the standard-resolution image. The digital signal group at the boundary between the divided screen and the adjacent divided screen, the brightness histogram of the divided screen, and management information are stored in the digital memory, and upon restoration, , based on the management information, reads the analog memory for each split screen, converts it digitally and writes it to the work area of the memory, creates a brightness histogram from the digital signal of the work area, and stores this in the digital memory. The output of the work area is corrected so that it is equal to the histogram of the divided screen, and the digital signal group corresponding to the boundary part is read out from the work area based on the management information to eliminate blurring. The present invention is characterized in that the work area readout address is corrected so that it overlaps with the digital signal group at the boundary part stored in the digital memory, and a high-resolution image signal is output from the work area by performing such correction. , which will now be described in detail with reference to the drawings.

Embodiment of the invention FIG. 1 shows an embodiment of the invention. 10 is 1024×10
It shows a high-resolution image consisting of 24 pixels, specifically a signal group of the image or a memory (screen memory) that stores it. Since one pixel signal includes luminance information, etc., it is represented by a plurality of binary bits, and therefore the screen memory has a depth corresponding to the plurality of hints. 20 is a video disk, 22 is a video tape recorder (VTR), and these are made according to the NTSC system, so one screen is 512 x 512
An image signal consisting of only five pixels is recorded in the form of an analog signal. In the present invention, a 1024 x 1024 pixel screen is divided into 4 equal parts and 41 512 x 512 screens (called subframes or split screens) 12, 14, 16, 18
Each of them is digital-to-analog converted by the D/A converter 24 to produce a signal S1 for one screen of the NTSC system, and this is recorded in the memory 20 and/or 22. The image signal at the boundary between adjacent subframes, which is indicated by diagonal lines, is also stored in digital form on the magnetic disk 30, or in other words, in the digital memory 30. 30a is its storage area. The digital image signal of each subframe is also input to the histogram processing device 26, which calculates the luminance distribution of each pixel (luminance B1 is Nri, B2 is N2 (brightness...
...) is determined, and the brightness distribution is stored in another area 30c of the magnetic disk 30. Management information is also recorded on the magnetic disk 30, and this management information is derived from the 1-rank position of the video memory 20.22 where each subframe is recorded, the position information on the disk 30 where the boundary image and histogram are stored, etc. Become.

In this way, the high-resolution image signal for one screen is converted into a standard resolution 4
The signals corresponding to the screen are recorded in the memories 20 or 22 and 30, and read out and restored to high-resolution image signals using the circuits shown in FIGS. 2 and 3.

In FIG. 2, 20 and 22 are the video discs and VTs mentioned above.
R130 is a magnetic disk. , the memory 20.22 is read out based on the management information of the area 30d of the magnetic disk 30, and this memory read analog output is converted into a digital output by the converter 28, and the 512 x 512 pixels of the memory 32 are temporarily converted for the next histogram processing. into the work area 32a, which has a capacity of This work area 32a corresponds to the aforementioned subframe. Next, this work area 3
2a and writes the readout output to a work area 32b of a similar capacity in the memory 32, but this readout output is also input to the histogram processing unit 36, which calculates the approximately 1 degree distribution of pixels. . This is compared with the luminance distribution read from the area 30c of the magnetic disk 30 by the comparison processing device 38, and the comparison processing device 38
The output of 8 modifies the brightness of the image signal transferred from memory 32 to memory 34. In this way, brightness is reproduced.

Next, as shown in FIG. 3, the boundary portion of the work area 32b is read based on the management information of the magnetic disk 30, and the comparison processing device 34 compares it with the boundary image signal stored in the areas 30a and 30b of the magnetic disk. Align so that they match. To explain the positioning procedure with reference to FIG. 4, the restored image 42 from the boundary part of the work area 32b and the magnetic disk 3
The boundary image 44 from 0 is compared based on the pixel address to determine the shift between the two images. If there is a shift, the iU original image is shifted in steps (in units of multiple pixels) in the x and y directions, and specifically, the readout shear address of the work area 32b is shifted relative to the readout address of the area 30a of the magnetic disk. ,
Both images 42 and 44 should be aligned. In reality, unless the difference is smaller than a certain value, it will be rejected as impossible to synthesize), and from that state further x
If the difference further decreases by shifting in the +y direction, the position after the shift is selected, and conversely, if the difference increases, the position before the shift is selected. After making this step-by-step selection, we perform pixel-by-pixel processing, that is, shift processing in the x+y direction, in the same way.
Perform final positioning.

In this way, the brightness and position of the image digital signal in the work area 32b are corrected (as correct) based on the histogram and boundary image signal of the disk 30, and the corrected data is stored in the 512 x 512 pixel subframe file in the memory 40. It's crowded. Perform the same process 4 times to obtain 1024X 10
24 high-resolution image signals are obtained, and the power arching process is repeated for each screen.

In the example, the high-resolution image consists of 1024 x 1024 pixels, and the split screen (sub frame) is 512 x 5 pixels.
Although it is made up of 12 pixels, this is of course only an example, and any pixel density may be used. Also, the long side of the boundary part naturally has the same number of pixels as the split screen, which is 512 pixels in the example, but
The short side has an appropriate number of pixels, for example, about 10 pixels.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, it is possible to store a high-resolution digital image signal in a standard-resolution analog image memory and reproduce it to obtain a high-resolution digital image signal without positional deviation or brightness deviation. can.

[Brief explanation of the drawing]

Figure 1 is a diagram explaining the storage method of the present invention, Figures 2 to 4
The figure is a diagram explaining the restoration method of the present invention. In the figure, 10 is a high-resolution image, 12, 14, 16° 18 are its divided screens, the shaded area is a boundary, 20° 22 is an analog memory, 30 is a digital memory, and 32a is a work area.

Claims (1)

[Claims] One screen of a high IW resolution image is divided into multiple screens of standard resolution images, and the digital image signal of each of the divided screens is converted into an analog signal and stored in an analog memory for standard resolution images. A group of digital signals at the boundary between a divided screen and an adjacent divided screen, a brightness histogram of the divided screen, and management information are stored in a digital memory, and restoration is performed based on the management information. The analog memory is read out for each split screen, converted into digital signals, and stored in the work area of the memory. A brightness histogram is created from the digital signal of the work area, and the blur is stored in the digital memory for the corresponding split screen. The readout output of the work area is corrected to be equal to the histogram of the management II! ? 913, read out a digital signal group corresponding to the boundary part from the work area, correct the work area read address so that it overlaps with the digital signal group of the boundary part stored in the digital memory, and make a correction. A method for accumulating and restoring high-resolution image signals, the method comprising: outputting high-resolution image signals from the work area.