JPS63304790A - Picture processing method - Google Patents

Abstract

PURPOSE:To obtain a residual effect by dividing a screen into plural areas and writing picture data of respective points into respective corresponding storage positions by means of a memory only in a period which has been selected at every plural areas among plural periods existing in four field periods. CONSTITUTION:The memory 25 writes picture data into respective storage positions only when high level signals are outputted from an AND gate 24. Consequently, the memory 25 writes pictures. data of respective points of light areas A and B into corresponding storage positions in one field among continuous four field periods. Since the area A shifts, new picture data is not written in the storage position to which picture data of respective points of the area A before the area A shifts. As a result, the picture with the residual image can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing method, and particularly to a method of processing an image using a memory.

1. Image processing such as reduction, enlargement, and movement of the image is performed by digitizing the composite video signal and writing it into memory, and reading the digitized composite video signal from the memory by specifying an address different from that used when occupying the image. can be done. Also,
An afterimage effect can be obtained by writing only a part of the composite video signal into the memory and combining that part with other parts that have already been written and outputting the result.

However, for example, the frequency fsc of the color sub-channel of an NTSC video signal is set to a frequency as shown in the following equation, where fH is the horizontal synchronization frequency and t'v is the vertical synchronization frequency.

f sc = -one bone f H = □ □
f v455x525 = □・t'v (1) Therefore, if you try to synthesize and output composite video signals written in an arbitrary period, the continuity of the color subcarriers of the output video signal will be lost. As a result, a normal color image cannot be obtained.

Therefore, an image processing apparatus as shown in FIG. 7 was devised which allows normal color images to be obtained.

In the figure, a composite video signal is supplied to a Y-C separation circuit 1 and separated into a luminance signal Y and a color signal C. The luminance signal Y is supplied to the memory 3 after being converted into a digital signal by the A/D conversion 2I2. The color signal C is supplied to the color demodulator 4, and the color difference signals RY and [3-Y are demodulated. These color difference signals R-Y and B-Y are converted into digital signals by A/D converters 5 and 6, respectively, and then supplied to the memory 3.

The memory 3 is subjected to address control and the like by a memory controller 7, and is loaded with a digitized luminance signal Y and color difference signals RY and BY. When the luminance signal Y and the color difference signals R-Y and B-Y are read out from the memory 3, they are supplied to D/A converters 8.9 and 10 and converted into analog signals. The color difference signals R-Y and B-Y converted into analog signals are supplied to a modulator 11$:', where the color subcarriers are modulated to form a color signal C. This color signal C is supplied to an adder circuit 12 and then D/A
The luminance signal Y output from the converter 8 is processed and filtered to synthesize a composite video signal.

The circuit described above has the disadvantage that the configuration is complicated and the image quality deteriorates because the color signal passes through the demodulator and modulator.

Therefore, an object of the present invention is to provide an image processing method that can obtain an afterimage effect without deteriorating image quality using a circuit with a simple configuration.

The image processing method according to the present invention divides a screen on which an image is formed by a composite video signal into a plurality of regions, and writes image data of each point of the plurality of regions to each corresponding storage location of a memory. It is characterized in that it is carried out only in periods selected for each of a plurality of regions from the back of a plurality of periods existing in a four-field period.

Branch-1 Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 6.

In FIG. 1, a composite video signal is supplied to an A/D (analog-to-digital) converter 21, a field period processing circuit 22, and a signal comparison circuit 23 via an input terminal IN. The A/D converter 21 samples the composite video signal at a predetermined sampling frequency, and generates image data according to the obtained sample values. Image data output from this A/D converter 21 is supplied to a memory 25. The memory 25 has a storage capacity sufficient to store, for example, all the image data generated during one field period, and has a plurality of storage locations corresponding to each point on the screen where an image is formed by the composite video signal. have.

The field period processing circuit 22 is configured to generate positive polarity pulses as shown in FIG. 2, which are generated at four field periods and have a pulse width corresponding to one field period, according to the vertical synchronization signal in the composite video signal. ing. The output pulse of the field period processing circuit 22 is supplied to one input terminal of a two-manual AND (logical product) gate 24.

The output of the level comparison circuit 23 is supplied to the other input terminal of the AND gate 24. The level comparison circuit 23 is
The composite video signal is compared with a reference level vr, and when the instantaneous level of the composite video signal exceeds the reference level vr, a high level signal is output.

The output of AND gate 24 is provided to memory controller 526. The memory controller 26 controls the memory 25 so that image data sequentially supplied to the memory 25 is sequentially written to corresponding storage locations, and data stored in each storage location of the memory 25 is sequentially read out in a predetermined order. . In this memory controller 26, AN
The high level signal output from the D gate 24 is designed to act as a write command signal, and image data is written to each storage location in the memory 25 only when the high level signal is output from the AND gate 24. Writing is performed.

The image data read from the memory 25 is supplied to the D/A converter 27 and converted into an analog signal, and then supplied to the output terminal OUT and sent to a video reproduction device such as a color monitor.

In the above configuration, the third
The operation of each section when a composite video signal corresponding to a 1ifl image as shown in FIG. 1A is supplied will be described. now,
ff114 where the reference level Vr applied to the level comparison circuit 23 is lower than the instantaneous level of the part corresponding to bright areas and B of the composite video signal and other than areas A and B.
It is assumed that the instantaneous level is set to be higher than the instantaneous level of the part corresponding to . Then, when the bright area of the composite video signal and the part corresponding to B are supplied to the level comparison circuit 23, a high level signal is output from the level comparison circuit 23, and the AND gate 24 outputs a high level signal for one field period with a four field cycle. A high level signal is output throughout the period. Furthermore, when the portion corresponding to areas other than areas A and B is supplied to the level comparison circuit 23, the level comparison circuit 23
Since the output of the AND gate 24 is at a low level, the output of the AND gate 24 is also at a low level.

Since image data is written to each storage location of the memory 25 only when a high level signal is output from the AND gate 24, the image data of each point of the bright area Δ and B is stored in each memory 25 corresponding to each point. Continuous writing to the position 4
This is performed only in one field period after the other field period.

Furthermore, since area A has moved, new image data will not be written to the storage locations where image data for each point in area A was written before the movement of area tiAA. This beam formation results in an image with an afterimage as shown in FIG. 3 (8). At the same time, the image data for the part where the afterimage is formed is written in a four-field cycle, so the phase continuity of the color subcarriers in the part where the afterimage is formed and the other parts is maintained. Good color reproduction is possible.

Note that although images for three fields out of the four-field period are thinned out, reproduced images for 15 fields are output per second, so the normal image can be perceived as a moving image.

FIG. 4 is a block diagram showing another embodiment of the present invention, including an A/D converter 21, a field period processing circuit 22, a level comparison circuit 23, an ANE gate 24, a memory 25,
The memory controller 0-26 and the D/A converter 27
Connected in the same way as the device shown in the figure. However, in this example, the reference level supplied to the level comparison circuit 23 is output from the integration circuit 28. Integrating circuit 28 is supplied with an input composite video signal.

In the above configuration, since the reference level supplied to the level comparison circuit 23 changes according to the average brightness level of the input composite video signal, a moderate afterimage can be produced even when the overall brightness level is high or low. It has the advantage of being able to benefit from the Song Dynasty.

In the above embodiment, image data of each point in the area where the instantaneous level of the composite video signal is high is written.
Image data may be written at each point in an area where the instantaneous level of the composite video signal is low. In addition, in the above embodiment, the screen was divided according to the instantaneous level of the composite video signal, but the screen is divided into nine parts as shown in FIG. It is also conceivable to perform writing in area B with a period of 16 fields as shown in FIG. It may be changed.

As described in detail above, the image processing method according to the present invention divides a screen on which an image is formed by a composite video signal into a plurality of regions, and stores image data of each point in the plurality of regions in each corresponding memory. Since writing to the storage location is performed only in a period selected for each region from among a plurality of periods existing in a 4-field period, the continuity of the color subcarrier is maintained and the modulator modulates and demodulates the color signal. In addition, color reproduction can be performed satisfactorily without the need for a demodulator, and an afterimage effect can be obtained without deteriorating image quality due to the round circuit configuration.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is a field periodic processing circuit 22 in the device shown in FIG.
3 is a diagram showing the operation of the device shown in FIG. 1, FIG. 4 is a block diagram showing another embodiment of the present invention, and FIG. 5 is a diagram showing a method of dividing the screen. 6 is a diagram showing the write timing of each storage location of the memory corresponding to each point of each area when divided as shown in FIG. 5, and FIG. FIG. Explanation of symbols of main parts 22...Field cycle processing circuit 23...
...Level comparison circuit 25...Memory

Claims (2)

[Claims] (1) A composite video signal of each point on the screen obtained by sampling the composite video signal in a memory having a plurality of storage locations corresponding to each point on the screen where an image is formed by the composite video signal. Image processing is performed by sequentially supplying a plurality of image data according to the level of the data and writing it into each of the plurality of corresponding storage locations, and then sequentially reading out the storage data in the plurality of storage locations in a predetermined order. A processing method that divides the screen into a plurality of regions, and writes image data of each point of the plurality of regions to each corresponding storage location of the memory in a period of four field periods. An image processing method characterized in that the image processing is performed only in a period selected for each of the plurality of regions from among the periods. (2) The image according to claim 1, wherein the instantaneous level of the composite video signal is compared with a predetermined reference level, and the screen is divided into a plurality of regions based on the comparison result obtained. Processing method.