JPS62150973A - Picture-quality adjusting device for television receiver - Google Patents

Abstract

PURPOSE:To automatically adjust to obtain a maximal quality of a picture by detecting the variation of a brightness signal in horizontal and vertical directions by storing a television video signal, deciding a variation in brightness- level for a time longer than a prescribed time and higher than a prescribed level, and controlling the detection signal to adjust the contour of the video signal. CONSTITUTION:By means of a picture memory 1, the video signals of points A, x1, x2, y1, and y2 on the screen of a television receiver. The monotonousness of the data of the points in horizontal direction A, x1, and x2 and that of the ones A, y1, and y2 are decided by an arithmetic unit 2. The levels of the respective data are decided by decision circuits 3 and 4 for horizontal and vertical directions. Only when there is, respectively, a variation higher than the prescribed level and longer than the prescribed time, contour correcting circuits 5 and 6 for horizontal and vertical directions are actuated to adjust the quality of a picture.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an image quality adjustment device for a television receiver.

Conventional Technology Television receivers are equipped with image quality adjustment circuits, but conventionally, the focus has been on contour correction in the horizontal direction. However, recently, 2H using digital method.

With the development of television signal processing circuits and the ability to store video signals in memory, vertical contour correction has also become possible.

Problems to be Solved by the Invention However, with conventional image quality adjustment devices, the user has to manually adjust the image quality, and when broadcast waves change, it becomes difficult to adjust the points. there were.

Additionally, contour correction does not emphasize high frequencies, but has the disadvantage of increasing noise.

The present invention aims to eliminate these drawbacks and provide an apparatus that can automatically adjust the image quality to the optimal point at all times and can suppress the generation of noise as much as possible.

Means for Solving the Problems In the present invention, a television video signal is stored using an image memory, changes in the brightness signal in the horizontal and vertical directions are detected, and the brightness level changes over a predetermined time and at a predetermined level. Determine when to do so.

This can easily be done by using a digital signal processing circuit. Next, the detection signal is controlled to perform contour correction on the video signal.

By doing this, it is possible to automatically adjust to obtain the optimum image quality without manual intervention.

Moreover, because the noise is of low level and occurs randomly in time, it is not detected by the circuit described above and does not emphasize the noise.

Embodiment FIG. 1 shows a block diagram of an image quality adjustment circuit according to an embodiment of the present invention, and FIG. 2 shows the principle of brightness level detection.

FIG. 2a shows the screen of a television receiver. A
Sample point "1) x 2 in the horizontal direction (X direction) centering on the point
Then, a sample point 31tV2 is taken in the vertical direction (y direction). In this case, data sampled at the sampling frequency of image processing is used in the X direction, and scanning lines are used as sample points in the y direction. Taking the X direction as an example, b shows four cases in which time is plotted on the horizontal axis and brightness level is plotted on the vertical axis.
Case A is a case where the brightness of the single house is high, the brightness of the mouth is single and low, and cases B and 2 are cases where the brightness changes slightly up and down. Therefore, in cases ``A'' and ``2'', it is determined that the level change of the luminance signal is longer than a predetermined time and at a predetermined level, and in ``C'' and 2, it is determined that the change is less than a predetermined time or a change less than a predetermined level, such as noise. .

FIG. 1 shows an embodiment of the image quality adjustment circuit, in which image memory 1, points A, xl, x2, . The video signals of yl and y2 are stored. Then, the arithmetic circuit 2 calculates A in the horizontal direction.
, X11 X2 data monotonicity and vertical A
, yl, y2 are determined, and their levels are determined by the horizontal and vertical determination circuits 3 and 4, and only when there is a change of more than a prescribed level for a predetermined time or more, respectively. The image quality is adjusted by operating the horizontal and vertical contour correction circuits 5 and 6.

FIG. 3a shows an example of a video signal, and b shows the signal after correction. Both C and C were determined to be noise, so no contour correction was performed and the original video signal was output. In both the A and mouth portions, it is determined that the brightness 5 page degree level changes for more than a predetermined time and at a predetermined level, and the contour is corrected and the slope is increased.

Effects of the invention As described above, according to the optical invention, the user can
Adjustment is made so that the optimum image quality is automatically obtained in a predetermined screen state, and furthermore, the adjustment is made so that the image quality becomes sharp without increasing noise.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of an image quality adjustment device for a television receiver according to an embodiment of the present invention, FIG. 2 is a diagram of its operating principle, and FIG. 3 is a waveform diagram showing its effect. 1... Image memory, 2... Arithmetic circuit,
3, 4... Determination circuit, 5... Horizontal direction contour correction circuit, 6... Vertical direction contour correction circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 5-6 Second cause ((L) (b) Figure 3

Claims (1)

[Claims] storing a television video signal, detecting changes in the brightness level in the horizontal and vertical directions on the screen, and operating a horizontal contour correction circuit when the brightness level changes in the horizontal direction for more than a predetermined time and at a predetermined level; An image quality adjustment device for a television receiver that operates a vertical contour correction circuit to correct the image quality of an original video signal when the image changes in the vertical direction for more than a predetermined time and at a predetermined level.