JPH01126670U - - Google Patents

Description

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an NTSC system image correlation compatible luminance signal/chrominance signal separation filter according to an embodiment of the invention, FIG. 2 is a block diagram showing an embodiment of the image correlation determination circuit, and FIGS. Figure 4 shows the first determination part of the image correlation determination circuit described above.
FIG. 5 is a block diagram of a conventional luminance signal chrominance signal separation filter, and FIG. 6 shows synchronous sampling of an NTSC system composite color television signal at four times the color subcarrier. FIG. 2 is an explanatory diagram showing an arrangement of signal sequences on a screen. In the figure, 1...input terminal, 2, 3...output terminal, 4...A/D converter, 5a-5j...delay circuit, 6a-6k...digital filter, 7...
...Image correlation determination circuit, 8...Switch circuit, 9a
~9c...Subtraction circuit, 10a-10e...Absolute value circuit, 11a-11e...Comparison circuit, 12a-1
2e... Constant generation circuit, 13a... Vertical correlation detection circuit, 13b... Horizontal correlation detection circuit, 14... Judgment circuit, 15a to 15e... AND circuit, 16a
, 16b...OR circuit, 17a-17d...NO
T circuit. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims for Utility Model Registration] A composite video signal sampled at a predetermined frequency synchronized with the horizontal scanning frequency so that each sample point is arranged in a grid on the screen is input, and from this composite video signal, digital In a luminance signal/chrominance signal separation filter for image correlation that separates a luminance signal component and a chrominance signal component, a sample point of interest at which the luminance signal and chrominance signal should be separated by delaying the composite video signal and the sample point of interest on the screen; delay means for simultaneously obtaining sample values of a plurality of reference sample points arranged in a straight line in the vertical direction; a vertical color signal extraction filter that extracts and outputs a frequency component corresponding to a component of the color subcarrier in the horizontal direction; A horizontal color signal extraction filter that outputs a horizontal color signal extraction filter; and a horizontal color signal extracting filter that receives the sample point of interest and a predetermined reference sample point as input, and extracts and outputs frequency components corresponding to color subcarrier components in both the vertical and horizontal directions.
A vertical color signal extraction filter, which inputs the sample values of the sample point of interest and a predetermined reference sample point, and in the frequency component of the sample point of interest, a low frequency component in the vertical direction and a color sub-frequency component in the horizontal direction. horizontal high-frequency luminance signal energy detection means for extracting a frequency component corresponding to one-half of the carrier wave frequency and determining its absolute value to detect horizontal high-frequency luminance signal energy; The sample value of the reference sample point is input, and the frequency component at the sample point of interest is a low frequency component in the horizontal direction and a frequency component corresponding to one-half of the color subcarrier frequency in the vertical direction. , vertical high frequency luminance signal energy detection means for detecting vertical high frequency luminance signal energy by determining its absolute value; , the horizontal high-frequency luminance signal energy is smaller than the first setting value, and the vertical high-frequency luminance signal energy is compared with a second externally applied second setting value, and the horizontal correlation detection means for determining that there is a correlation in the horizontal direction when the vertical high frequency luminance signal energy is larger than the second set value; Compare the magnitude with a set value, and determine that the vertical high range luminance signal energy is smaller than the third set value, and the horizontal high range luminance signal energy is larger or smaller than the fourth set value given from the outside. vertical correlation detection means that compares the horizontal high-frequency luminance signal energy and determines that there is a correlation in the vertical direction if the energy of the high-frequency luminance signal is larger than the fourth set value; input the value, exclude frequency components corresponding to the DC component and the color subcarrier component in the diagonally upward right direction on the screen from the frequency components at the sample point of interest,
a diagonally upward-sloping direction uncorrelated energy detecting means for detecting the diagonally upward-sloping direction uncorrelated energy by determining the absolute value thereof; and a frequency component at the noted sample point that receives sample values of the sample point of interest and a predetermined reference sample point as input. diagonally downward-rightward uncorrelated energy detection means for detecting obliquely downward-rightward uncorrelated energy by excluding frequency components corresponding to the DC component and the color subcarrier component in the diagonally downward rightward direction on the screen and finding their absolute values; and bi-diagonal energy comparison detection for determining whether the absolute value of the difference between the diagonally upward-rightward uncorrelated energy detection result and the diagonally rightward-downward uncorrelated energy detection result is larger or smaller than a fifth set value given from the outside. means, inputting the determination result of the vertical correlation detection means, the determination result of the horizontal correlation detection means, and the determination result of the both diagonal energy comparison detection means, and determining the magnitude and smallness of the determination results of the two diagonal energy comparison detection means; Control for selecting the output of the horizontal color signal extraction filter, the vertical color signal extraction filter, or the horizontal/vertical color signal extraction filter according to the determination result of the presence or absence of correlation in the horizontal and vertical directions. A determination means for sending out a signal; a switch circuit for outputting a color signal component according to a control signal of the determination means; and a subtraction circuit for subtracting the output of the switch circuit from the composite video signal to output a luminance signal component. A luminance signal color signal separation filter that supports image correlation.