JPS6229297A - Enlarging method for television picture - Google Patents

Abstract

PURPOSE:To enlarge a part of a televison picture without separating a luminance signal and a chrominance component by setting an interpolation value of wave length unit of a color burst signal as the average value of picture signals existed as the preceding and succeeding signals to be interpolated, based upon the color burst signal in an enlarging and interpolating process. CONSTITUTION:A digital picture signal at each corresponded m-th and m+1-th sampling point in each of buffer memories 13 and 14 is subtracted by a subtractor 15, and the output is divided into two (is averaged) by a divider 16, and by an adder 17, they are added with the digital picture signals at the buffer memories 13 and 14, generating the average value of the preceding and the succeeding picture signals to be interpolated. Assuming that the difference between the m-th signal and the m+1-th one is multiplied by n-number of the wavelength of the color burst signal and the first sampling value is (m', x, 1), the x-th interpolation signal is represented as (m',x,1)=(m,1)+[(m+1,1)+(m,1)]Xx/n in an usual expression, and by solving the usual expression, a required average interpolating signal can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a television image enlarging method for enlarging and displaying a portion of a color television screen.

(Prior Art) Recently, a portion of a single television screen has been enlarged and displayed.

Figure 6 shows a conventional circuit for assembling an NTSC color television image signal (hereinafter simply referred to as an image signal) for this purpose.
FIG. 2 is a block diagram showing a circuit configuration that allows a portion of a television screen to be enlarged without separating the screen into two parts.

In FIG. 6, 1 is a synchronization separation circuit that separates a synchronization signal from an image signal V by S, 2 is an analog-to-digital converter (hereinafter referred to as an A/D converter), 3 is a memory for storing its digital output, and 4 is a digital-to-analog converter (hereinafter referred to as a D/A converter) that converts the digital output read from the memory 3 into analog again, 5 is an enlargement processing control circuit, and 6 is a synchronization signal S and a horizontal scanning color subjected to enlargement processing. This is a synchronous combining circuit for combining the image signal C and obtaining an NTSC image signal again.

The television image enlarging circuit configured as shown in FIG.
A synchronizing signal S is separated from the horizontal scanning color image signal C.
is directly quantized and converted into a digital signal by the A/D converter 2, and the signal is stored in the memory 3 according to the memory access of the enlargement processing control circuit 5. The stored digital signal is converted into an analog signal by the output/A converter 4, sent to the synchronization coupling circuit 6, and combined and synthesized with the synchronization signal S directly applied from the synchronization separation circuit 1. An image signal is created that enlarges and displays a portion of the television screen.

Figure 7 is a diagram showing the algorithm of the enlargement circuit in Figure 6.
(a) shows a portion of a continuous wave of a specific color signal of an NTSC image signal, and its color component is represented by a phase difference with the color burst signal. When enlarging such an image signal, conventionally, as shown in (b), one wavelength of the color burst signal is used as a unit, and the mth (m is any positive integer, the same applies hereinafter) signal and the mth Between the +1st signal, the signals before and after it, that is, the mth and m+th signals
The first signal is inserted and interpolated as it is, and the phase relationship between the color signal and color burst signal in the enlarged image signal is maintained unchanged from before enlargement, which is used to enlarge the TV image. I was doing it.

(Problems to be Solved by the Invention) However, in such a conventional television image enlarging method, the interpolation signal is an image signal in units of one wavelength of the color burst signal before or after interpolation.

When the magnification is large, the same interpolation signal is used repeatedly, which has the disadvantage of lowering the horizontal resolution and resulting in an unnatural image.

In view of the above-mentioned drawbacks of the conventional television image enlarging method, the present invention provides an NTSC method that allows a natural image to be obtained instead of an unnatural image as in the conventional method even when a color burst signal is enlarged at a high magnification in wavelength units. The object of the present invention is to provide a method for enlarging a television image.

(Means for Solving the Problems) The present invention aims to achieve the above-mentioned object by changing the interpolation value in units of wavelength to the average value of the image signal before and after the interpolation, based on the color burst signal in the enlarged interpolation process. This can be solved by doing this.

(Function) The present invention interpolates the interpolation value using the average value of the image signals before and after interpolation, without separating the image signal into a luminance signal and a color signal. Uniform continuity is maintained, so a natural image can be obtained on the television screen.

(Example) Hereinafter, the present invention will be explained in detail by way of an example using the drawings.

FIG. 1 is a block diagram showing the circuit configuration of an embodiment of the present invention.The configuration of the present invention is the same as the conventional circuit configuration in terms of block diagram, so the configuration of FIG. 1 is similar to that of FIG. Match. To explain this without worrying about the complexity, 7 is a synchronization separation circuit that separates the synchronization signal S from the image signal V;
is an A/D converter.

9 is a memory for storing the digital output, 10 is a D/A converter for converting the digital output read from the memory 9 into analog again, 11 is an enlargement processing control circuit, and 12 is a synchronization signal S and an enlarged image signal. and again NT
The television image enlarging circuit configured as shown above, which is a synchronization coupling circuit for producing an SC system image signal, first separates the synchronization signal S from the NTSC system image signal V using the synchronization separation circuit 7.

A horizontal scanning color image signal C is generated, which is directly quantized and converted into a digital signal by an A/D converter 8, and is stored in a memory 9. The enlargement processing control circuit 11 controls the enlargement processing of the signal in the memory 9 through its memory access,
The output is converted into an analog signal by a D/A converter 10 and sent to a synchronous coupling circuit 12.

By combining and synthesizing it with the synchronization signal S directly applied from the synchronization separation circuit 7, an image signal for enlarging a part of the NTSC television screen is created.

FIG. 2 is an explanatory interpolation diagram of FIG. 1, and shows the positional relationship between the color burst signal and the image signal in the NTSC system. Based on the first wavelength of the color burst signal,
The image signal is ordered every four sampling points (indicated by black circles) in units of wavelength, and the m-th first sample value is (m, 1), the second sample value is (m, 2), and the m-th sample value is (m, 2). The third sample value is (m, 3), the fourth sample value is (m, 4)
It is shown as follows.

FIG. 3 is a waveform diagram of an image signal explaining the algorithm of the present invention. For example, if the magnification is set to twice the wavelength as shown in the figure, the interpolation signal m' between the m-th and m+1-th signals is It can be expanded by generating as follows. That is, the first sample value of the interpolation signal m' is the average value of the first sample values of the m-th and m+1-th image signals before and after interpolation (m' -1) = (me 1) +
((m+1,l)-(m,1))/2, and the average value of the second to fourth Sunburi values is also found in the same way.

FIG. 4 is a block diagram of a circuit that generates this interpolation signal. 13.14 is a buffer memory, 15 is a subtracter, 1
6 is a divider, 17 is an adder, and buffer memory 13.1
4, respectively, the m-th and m+1-th.

The digital image signal of each corresponding sampling point is subtracted by a subtracter 15, and the output value is divided into two (averaged) by a divider 16, and then added to the digital image signal of the buffer memory 13 (or 14) by an adder 17. The addition creates an average value of the image signals before and after the interpolation.

FIG. 5 is a diagram generally illustrating the algorithm of the present invention in which the expansion wavelength ratio is n times. mth signal and m+1th signal
The distance between the th signal is multiplied by n of the wavelength of the color burst signal,
The X-th interpolation signal converts the first sampling value to (m
' t X, 1), then in the general formula, (m
' t xt l) = (m, 1) + ((rn + 1
* 1 ) + (me 1 )) It is expressed as Xx/n. That is, by solving the above general equation using, for example, the circuit shown in FIG. 4, the necessary average value interpolation signal can be obtained.

NTSC in which the luminance signal and color signal are balancedly modulated in this way
Even in the case of a digital TV image signal, by paying attention to the wavelength of the color burst signal and performing average value interpolation, it is possible to create an interpolated signal for image enlargement without damaging the phase relationship with the color burst signal.

Although the present invention has been described in detail above, it goes without saying that the average value interpolation signal can be created by software using a microprocessor or the like, without relying on the circuit configuration shown in FIG.

(Effects of the Invention) As is clear from the above description, the present invention maintains the phase relationship with the color burst signal and creates an interpolation signal for image enlargement using the average value interpolation method. Even in the case of an NTSC television image in which the chrominance signal and the chrominance signal are balanced-modulated, it is possible to partially enlarge the television image with a simple configuration without separating the luminance signal and chrominance signal.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram showing a circuit according to an embodiment of the present invention, FIG. 2 is a diagram showing the relationship between color burst signals and image signals, FIG. 3 is a diagram showing a 2x enlargement algorithm, and FIG. 4 is a block circuit diagram for generating an average value interpolation signal, Figure 5 is a diagram generally showing generation of an average value interpolation signal, Figure 6 is a block configuration diagram showing a conventional circuit, and Figure 7 is an enlarged diagram of the conventional example. FIG. 3 illustrates the algorithm of the method. 1.7... Synchronization separation circuit, 2,8... Analog-digital (A/D) converter, 3,9... Memory. 4.10... Digital-analog (D/A) converter,
5.11... Enlargement processing control circuit, 6,12... Synchronous coupling circuit, 13.14... Buffer memory, 15.
...Subtractor, 16...Divider, 17...Adder. Patent applicant: Matsushita Electric Industrial Co., Ltd. Figure 1 Figure 2 Figure 3 (m; 41 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] A synchronization separation circuit that separates an NTSC color television image signal into a synchronization signal and a horizontal scanning image signal, an analog-to-digital converter that directly quantizes the horizontal scanning image signal, and a memory for storing the output digital signal. memory to
an enlargement processing control circuit that controls the enlargement processing of the digital signal by controlling the analog-digital converter and the memory; a digital-analog converter that converts the digital output of the memory into an image signal; A synchronous coupling circuit that combines the separated synchronous signal and the output of the digital-to-analog converter enlarges the image signal to an integer multiple of the length of one wavelength of the color burst signal. A method for enlarging a television image, characterized in that the portion is interpolated in units of one wavelength of a color burst signal using the average value of image signals before and after interpolation.