JPH0270175A - Raster scanning signal and video sampling device - Google Patents

Abstract

PURPOSE:To efficiently take out large quantity of information included in a picture by providing a raster scanning signal with the synchronization start signal of a white level just before the start of an effective picture area, and subsequently, with a sampling synchronizing signal to alternate black and white levels. CONSTITUTION:In the sampling synchronizing signal 21 following a vertical synchronizing signal and a scanning signal with no picture signal, the synchronization start signal 22 of the white level enters one or more picture elements, at least, before it enters the effective picture area in the course of a back porch 6, and a sampling phase comparing signal 23 which starts from the black level in the effective picture area and repeats the black level and the white level alternately at every picture element enters by the number of effective picture elements, and a front porch 7 enters, and the signal 21 is finished. Then, the raster scanning signal 36 is received by a reception circuit 31 from an external part, and distributed to an image sampling circuit 32, a synchronizing separation circuit 33 and a sampling(SP) synchronization circuit 34. The circuit 32 samples and outputs the raster scanning signal 36 by using an SP clock 35. The start of the effective picture area is detected from the black level following the first white level.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a raster scanning signal and an image receiving device for the raster scanning signal.

[Background Art] A raster scan video is formed by repeating the following operations: starting scanning an image from the left end, turning the scan back to the left at the right end, and returning to the upper left end when the bottom right end of the image is reached.

Run 8. Wrapping of the line from the left end to the right end is performed using a horizontal synchronizing signal, and from the lower right end to the upper left end is performed using a vertical synchronizing signal.

FIG. 1(α)l(b) is a waveform diagram of the raster scanning signal starting from the vertical synchronizing signal 1 until the end of scanning for one image.

With vertical synchronization signal 1, scanning starts from the upper left edge of the image, scans to the right, and continues with scanning signal 6. When one scan is completed, water 7 synchronization signal 2 enters, turning the scan to the left and starting the next scan. Start scanning.

This is repeated until the lower right end of the image, and then the vertical synchronizing signal 1' returns the scanning to the upper left end, completing the scanning for one image.

In this scanning, all scanning signals do not contain image information, but scanning signals 3 and 5 without image information are placed before and after the vertical synchronization signal 10 for an appropriate period, and before and after the horizontal synchronization signal 2 for an appropriate period. There is a state where there is no signal (back porch 6, front porch 7).

This is because it was provided in consideration of the fact that it takes time to move the scanning line on the receiver side using the horizontal and vertical synchronization signals.

[Problem to be Solved by the Invention] When sampling such a video pixel by pixel, the horizontal synchronization signal 2 indicates the division of the pixels in the vertical direction, but the starting position of the effective image is uncertain; For pixels in the horizontal direction, the pixel division and the starting position of an effective image are undefined and depend on the signal transmission side.

Therefore, for image receivers where pixel position is important, if information for pixel alignment is not added on the receiver side,
Positioning requires time and skill because adjustments must be made on the receiver side for each received signal.

The present invention provides a raster scanning signal to which pixel position information is added from a transmitter side to a receiving system that needs to sample pixel by pixel, and receives the raster scanning signal and converts the pixel position information and the image. The present invention provides an image sampling device capable of separating pixels and sampling pixels based on pixel position information.

[Means for Solving the Problems] In order to solve the above problems, the raster scanning signal of the present invention is set to the white level from at least one pixel immediately before the start of the effective display area in the horizontal direction, and then set to the effective level starting from the black level. It is characterized in that a sampling synchronization signal that alternately repeats a black level and a white level for each pixel by the number of pixels is superimposed for one scanning line on the invalid video scanning signal immediately before the start of the effective display area in the vertical direction.

The video sampling device of the present invention includes a signal separation circuit that separates the sampling synchronization signal from the raster scanning signal, a display area detection circuit that detects the starting horizontal and vertical position of the effective display area from the sampling synchronization signal, and a sampling synchronization signal. A video signal separation circuit that separates a video signal from a video signal, a reference signal generation circuit that generates a sampling reference signal that generates a signal with a frequency twice the fundamental frequency of the video signal, and a phase of the sampling reference signal that is compared with the pixel position. It is characterized by an additional sampling phase comparison circuit of []1u.

[Operation] Since the raster scanning signal of the present invention has a sampling synchronization signal added immediately before the start of the effective image area, by detecting the sampling synchronization signal, it can be determined that the next and subsequent scanning signals are in the effective image area. .

Furthermore, when the self-level signal that first appears from the sampling synchronization signal is detected, the start of the effective image area in the horizontal direction can be recognized from the subsequent black level.

Starting from the black level immediately after the white level signal that first appears, the black level and white level alternately change for each pixel, so by adjusting the frequency and phase of the sampling clock to twice the frequency of this change, Pixel-by-pixel sampling becomes possible.

[Examples] Hereinafter, the present invention will be described in detail based on Examples.

FIGS. 2(α), (b), and Ct) are waveform diagrams of raster scanning signals of the present invention.

After the vertical synchronizing signal 1, a scanning signal 3 without image information continues for an appropriate period, and then a sampling synchronizing signal 21 is input until the next horizontal synchronizing signal 2'. After the horizontal synchronization signal 2', the scanning video signal 4 that forms an image continues for a suitable period, and finally the scanning video signal 5 with no image information is input, and the vertical synchronization signal 1' is input and the raster scanning signal for the next image is input. Continue.

In the sampling synchronization signal 21, the sampling synchronization start signal 22 of the white level is input from at least one pixel before entering the effective image area in the middle of the back porch 6 (from 4 pixels before in Figure C), and the black level is input within the effective image area. Starting from , a sampling phase comparison signal 25 that alternately repeats the black level and white level for each pixel is input for the number of effective pixels, and ends when the front porch 7 corresponding to the frame on the right side of the image is input.

In the scanning video signal 4, after the horizontal synchronization signal 2 is input and the back porch 6 is input, a signal whose amplitude corresponds to the brightness of the pixel continues, and when the front porch 7 is input, one scanning line ends.

The sampling phase comparison signal 23 is matched in phase with the pixel position of the scanning video signal 4. FIG. In the example, Cb) is an embodiment of a receiver for receiving the raster scanning signal of the present invention in the form of a composite synchronization signal.

A receiving circuit 31 receives a raster scanning signal 36 from the outside,
It is distributed to the video sampling circuit 52, the synchronization separation circuit 33, and the sampling synchronization circuit 34.

The video sampling circuit 52 samples the raster scanning signal 56 using the sampling clock 55 and outputs it.

The synchronization separation circuit 53 separates a vertical synchronization signal 57 and a horizontal synchronization signal 58 from the raster scanning signal 56.

FIG. 4 shows an embodiment of the sampling synchronization circuit.

The sampling synchronization circuit '54 includes a sampling synchronization start signal detection circuit 41, a variable frequency sampling clock generation circuit 42, a sampling frequency phase tuning circuit 44, and a sampling start position measurement circuit 45.

The operation of the sampling synchronization circuit 54 is divided into an initial setting mode and a normal synchronization mode.

When the synchronization circuit 34 is reset, it enters the initial setting mode, and then when the sampling synchronization signal 4 is input, it shifts to the normal synchronization mode.

In the initial setting mode, the sampling start position measurement circuit 4
3 is activated by the input of the vertical synchronization signal 370, and counts the number of horizontal synchronization signals 38 input from this point until the sampling synchronization start signal 7 is detected by the detection circuit 41.

This allows the vertical distance from the input of the vertical synchronization signal to the start of the effective image to be determined.

Further, the number of clocks from the input of the horizontal synchronization signal 68 to the end of the sampling synchronization start signal is measured using the horizontal sampling start position measurement clock.

This makes it possible to determine the distance in the horizontal direction from the input of the horizontal synchronization signal to the start of the effective image.

The vertical and horizontal distances to the start of these valid images are:
It is measured and recorded only in the initial setting mode, and the value does not change in the normal synchronous mode.

In normal synchronization mode, when vertical synchronization signal 37 is input,
After skipping the scanning line by a distance in the vertical direction, when the sampling synchronization start signal 7 is detected by the detection circuit 41, the sampling frequency phase tuning circuit 44 is activated and compared with the sampling phase comparison signal 8 to determine the frequency variable sampling clock. The phases of the sampling clock 65 output from the generation circuit 42 are matched.

Within the effective image, after waiting for sampling by a distance in the horizontal direction from the input of the horizontal synchronization signal, the sampling clock 35 is output and the video sampling circuit 52 starts sampling.

The sampling clock 3 is set by inputting the horizontal synchronization signal 58.
The transmission of 5 is stopped.

The frequency of the sampling clock 35 is SAMP.

It is twice the ring phase comparison signal.

[Effects of the Invention] According to the present invention, the image information of transmitted images of raster video, which could only be handled in units of images, can be easily handled in units of pixels, so that information equipment can efficiently extract a large amount of information contained in images. This has become possible and will have an effect on closer collaboration between images and information devices.

[Brief explanation of the drawing]

FIGS. 1(α) and 1(h) are waveform diagrams of conventional raster scanning signals. Figure 2 ((L), Cb)? (C) is a waveform diagram of the present invention and a raster scanning signal. FIGS. 3(α) and 3(b) are block diagrams of an embodiment of a video sampling device according to the present invention. FIG. 4 is a block diagram of an embodiment of the sampling synchronization circuit of the present invention. 21... Sampling synchronization signal 22...
- Sampling synchronization start signal 25...Sampling phase comparison signal 34...Sampling synchronization circuit 41...Sampling synchronization start signal detection circuit 42...Sampling clock generation circuit 43・
...Sampling start position measurement circuit 44...
...Sampling frequency phase tuning circuit and above Applicant Seiko Epson Co., Ltd. Agent Patent attorney Kizobe Suzuki (and 1 other person) (a) Figure 1

Claims (4)

[Claims] (1) At least one of the RGB video signals of raster scan video
In the type of video signal, the white level is set at least one pixel before the start of the effective display area in the horizontal direction, and then starting from the black level, the black level is set for each pixel by the number of effective pixels.
A raster scanning signal characterized in that a sampling synchronization signal that alternately repeats a white level is superimposed for one scanning line on an invalid video scanning signal immediately before the vertical start of an effective display area. (2) A raster scanning composite synchronous video signal characterized in that the sampling synchronization signal described above is superimposed by one scanning line on the invalid video scanning signal immediately before the start of the effective display area in the vertical direction. (3) A signal separation circuit that separates the sampling synchronization signal from the raster scanning signal according to claim 1; a display area detection circuit that detects the starting horizontal and vertical position of the effective display area from the sampling synchronization signal; and a video signal from the sampling synchronization signal. A video signal separation circuit that separates the video signal, a variable frequency sampling clock generation circuit that generates a signal with a frequency twice the fundamental frequency of the video signal, and a sampling frequency phase tuning that matches the frequency and phase of the sampling clock by comparing it with the sampling synchronization signal. A video sampling device characterized by being equipped with a circuit. (4) The video sampling device according to claim 3, further comprising a synchronization separation circuit that separates vertical and horizontal synchronization signals from the raster scanning signal according to claim 2.