JPH027683A - Noise eliminating device - Google Patents

Abstract

PURPOSE:To eliminate noise of an edge part by providing the 2nd subtractor subtracting an output signal of a low pass filter from an output signal of a limiter circuit, slicing the output signal of a high pass filter and adding an output signal of the 2nd subtractor and an output signal of the slice circuit. CONSTITUTION:A limiter 3 outputs a signal below a limiter level (a), a low pass filter 9 eliminates a high frequency noise component from the output of the limiter 3, a subtractor 10 subtracts an output signal of the low pass filter 9 from the output signal of the limiter 3 to extract only the noise part at the flat portion. A slice circuit 7 slices an output signal of a high pass filter 2 at a level (b), a noise component of the edge part of a large amplitude is extracted and an adder 8 adds it to noise component of the flat portion, decides the noise band eliminated by the low pass filter 4 and the result is outputted to the subtractor 5. Thus, not only the flat portion of the reproduced luminance signal but also the noise component of the edge portion is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a noise removal method for removing noise from a reproduced luminance signal of a magnetic recording and reproducing device (hereinafter abbreviated as VTR) capable of recording and reproducing video signals. It is related to the device.

2. Description of the Related Art A conventional noise removal device will be described below with reference to the drawings.

FIG. 2 shows a block diagram of a conventional noise removal device. In Figure 2, 1 is an input terminal into which a reproduced luminance signal is input, 2 is a high-pass filter that extracts high frequency components from the reproduced luminance signal input from input terminal 1, 3 is a limiter circuit, and 4 is a noise band A limiting low-pass filter, 5 a subtracter, and 6 an output terminal.

First, a VTR reproduction signal containing noise n=2 is input from the input terminal 1 as shown in FIG. 3A. The high-pass filter 2 extracts high-frequency components from the signal shown in FIG. 3A, and outputs a signal as shown in FIG. The limiter 3 extracts minute noise components below the limiter level from the signal shown in FIG. The subtracter 6 subtracts the output signal of the low-pass filter 4 from the reproduced luminance signal shown in FIG. This output signal is shown in FIG. 3C.

Problems to be Solved by the Invention However, in the above configuration, for example, noise in the high-frequency, large-amplitude part of the luminance signal, especially the edge part where the S/N is poor and is visually noticeable, passes through the limiter 3. Therefore, it is not possible to remove the noise at the edge part, and since it is the signal component that passes through the noise extraction limiter at the edge part, the signal component at the edge part may be missing. had the following issues.

In view of the above-mentioned problems, the present invention is capable of removing not only the noise component of the flat part of the reproduced luminance signal, but also the noise component of the large amplitude edge part, and also eliminates noise that does not cause the waveform of the edge part to become large. O Means for Solving the Problems In order to resolve the above problems, the noise removal device of the present invention provides the following:
an input terminal into which a luminance signal is input; and a first terminal connected to this input terminal. a 202nd signal path; a first subtractor that subtracts the output signal of the 20th signal path from the output signal of the 1st signal path; and a high-pass filter and limiter circuit provided in the 20th signal path. , a low-pass filter to which the output signal of the limiter is supplied; a 20th subtracter that subtracts the output signal of the low-pass filter from the output signal of the limiter; a slicing circuit that slices the entire output signal of the high-pass filter; The apparatus includes an adder that adds the output signal of the 20th subtracter and the output signal of the slice circuit.

Effect of the Invention With the above-described configuration, the present invention is able to attenuate noise at the edge portions of a luminance signal, which is large in noise level and visually unsightly, and which cannot be removed with conventional devices. Since it does not affect the minute signal components in the area, the details of the playback screen are not damaged, and it also compensates for signal loss at the edges, so the waveform does not have sharp corners. No way.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a block diagram of a noise removal device according to the present invention. In FIG. 1, the same reference numerals as those in FIG. 2 are the same or equivalent parts, so the explanation will be omitted. 7 is a slice circuit, 8 is an adder, 9 is a low-pass filter, and 10 is a subtracter.

The operation of the noise removal device configured as described above will be described below.

A signal containing noise n as shown in FIG. 3A is input to the input terminal 1, and a high frequency component is extracted by the no-i pass filter 2 as shown in FIG.

The limiter 3 outputs all signals below the limiter level a from the signal shown at the beginning of FIG. 3, and supplies them to the low-pass filter 9 and the subtracter 1o. The low-pass filter 9 removes noise components in a higher frequency range than the output of the limiter 3, and extracts the signal components in the output signal of the limiter 3, as shown in the third l;. The subtracter 10 subtracts the output signal of the low-pass filter 9 from the output signal of the limiter 3, and extracts only the noise component in the flat part as shown in FIG. 3E. The slicing circuit 7 slices the output signal of the high-pass filter 2 as shown in the opening of FIG. 3 at a slice level b, and extracts the noise component of the large amplitude edge portion as shown in FIG.
is the noise component of the flat part shown in Figure 3 E and the noise component of the large amplitude edge part shown in Figure 3, and then the noise component of the flat part and the large amplitude edge part shown in Figure 3 G is added. All noise components are supplied to the low-pass filter 4. The low-pass filter 4 determines the noise band to be removed and outputs it to the subtracter 5. The subtracter 5 eliminates noise n as shown in FIG.
'lThe noise component in the flat part and the noise component in the edge part with large amplitude are subtracted from the reproduced luminance signal including the noise component in the flat part and the noise component in the large amplitude edge part, and the Outputs the entire signal with noise components at the edges of the amplitude removed.

Effects of the Invention As described above, the present invention provides an input terminal into which a luminance signal component is input, a 1st to 20th signal path connected to this input terminal, and an output signal from the first signal path to the first signal path. a first subtractor for subtracting the output signals of the 20 signal paths;
a high-pass filter and limiter circuit provided in a 0 signal path, a low-pass filter to which the output signal of the limiter circuit is supplied, and a 20th subtracter that subtracts the output signal of the low-pass filter from the output signal of the limiter circuit; It is equipped with a slicing circuit that slices the entire output signal of the high-pass filter, and an adder that adds the output signal of the 20th subtracter and the output signal of the slicing circuit. , it is possible to completely remove noise from large-amplitude edge portions of luminance signals that are large in terms of noise level and visually unsightly.Also, since the signal at edge portions is fully compensated, it is possible to eliminate the loss of signals at edges. It is possible to obtain a neat effect in which the waveform does not become dull.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the noise removing device of the present invention, FIG. 2 is a block diagram of a conventional noise removing device, and FIG. 3 is a waveform diagram of each part. 1...Input terminal, 2...High pass filter, 3...Limiter circuit, 4...Low pass filter, 5...Subtractor, 6...
・Output terminal, 7...Slice circuit, 8...
...Adder, 9...Low pass filter, 1゜・
...Subtractor. Name of agent: Patent attorney Toshio Nakao and one other person Figure 3? Figure (g) (+)

Claims (1)

[Claims] an input terminal into which a luminance signal component of a video signal is input; first and second signal paths connected to the input terminal; and an output signal of the 20th signal path based on the output signal of the first signal path. a first subtracter for subtraction; a high-pass filter and limiter circuit provided in the twentieth signal path; a low-pass filter to which the output signal of the limiter circuit is supplied; a second subtracter that subtracts the output signal; a slicing circuit that slices the output signal of the high-pass filter;
A noise removal device comprising: an adder that adds the output signal of the second subtracter and the output signal of the slice circuit.