JPH07322092A - Signal adaptive filter processor - Google Patents

Abstract

PURPOSE:To select a filter suitable for the input video signal by counting a horizontal synchronizing signal and comparing it at a judgement part. CONSTITUTION:The horizontal synchronizing signal of the video signal inputted to an input part 1 is inputted to a terminal 12. A vertical synchronizing signal is inputted to a terminal 13. A counter 14 counts the horizontal synchronizing signal by taking the rise edge of the vertical signal from the terminal 13 as a start point with the synchronizing signal from the terminal 12. A discrimination part 15 discriminates it, then the frequency band of the input video signal is discriminated and is inputted to the control part 16. The control part 16 reads out the type of the adaptive filter from a table 17 based on the discrimination result. A control part 18 outputs a switching signal to a switch control terminal 19, switching the changeover terminal 4 of the switch 3. Thus the connection with the adaptive filter to the inputted video signal is performed. Thus, the selecting of the adaptive filter can be automatically performed and an excellent screen without deterioration of picture quality due to the folding error can be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a video signal processing device that performs D / D conversion and signal processing.

[0002]

2. Description of the Related Art For example, in a plasma display device which requires a video signal processing unit for converting an input analog video signal into a digital signal, an A / D for converting the analog video signal into a digital signal. It is known that a converter is required, and in this case, the sampling frequency of the A / D converter must be sampled at a sampling frequency that is at least twice the maximum value of the frequency band that handles the analog input signal. There is. On the other hand, 1/2 of the sampling frequency in the input analog signal
A component of a frequency band that exceeds twice becomes a folding error, and such a folding error causes noise on the screen displayed by the D / A converted signal, which causes deterioration of image quality. Therefore, it is desirable to remove the components in the frequency band that exceeds 1/2 the sampling frequency by a filter or the like before performing the D / A conversion. However, in the case where the video signal processing unit can input, in addition to the NTSC signal, video signals having different frequency bands such as wide band, VGA, personal computer, etc. The signal would have the problem of having to provide selection means to select the filter that best matches the signal.

[0003]

When the video signals of a plurality of frequency bands are input and A / D converted, as in the case of a wide television, a VGA, a personal computer, etc., as in the above-mentioned conventional technique, the respective signals are converted. Since a filter suitable for the video signal frequency band has to be selected, an object of the present invention is to provide a signal adaptive filter processing device capable of automatically selecting a suitable filter according to the frequency band of the video signal. To provide.

[0004]

In order to solve the above-mentioned problems, the present invention provides a video signal processing circuit having an A / D converter for inputting an analog video signal and A / D converting it.
An input unit for inputting a video signal having at least two or more kinds of frequency bands, a filter provided for each of the frequency bands, a counter for counting the number of horizontal scanning lines of the input video signal, and the number of horizontal scanning lines. A table having identification data of the filter corresponding to the count value of, a switching unit that switches the filter, and a switching control unit that outputs a switching signal to the switching unit based on the count value of the counter. Characterize.

[0005]

With the above construction, according to the signal adaptive filter processing method of the present invention, a video signal having a predetermined frequency band, its horizontal synchronizing signal, and vertical synchronizing signal are input to the respective input portions. Input to the terminal, the counter counts the number of horizontal synchronization signals starting from the rising edge of the vertical synchronization signal, determines the frequency band of the input video signal from the counted value, the control unit, the determination result Based on this, the type of filter is selected, and the switching control unit outputs a switching signal and switches the switch to connect with a filter suitable for the input video signal.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a signal adaptive filter processing system according to the present invention will be described in detail below with reference to the drawings. In FIG. 1, reference numeral 1 is an input section having a plurality of input terminals, and 2 is a common output terminal of the input terminals, which is connected to a switching terminal 4 of a switch 3. Reference numeral 5 denotes a terminal portion of a switch 3 for connecting a filter, one end of each of the filters 6, 7, 8, 9 is connected, the other end of each of the filters is connected to a clamp 10, and an output of the clamp 10 is A / D converted. Connected to the container 11. 12 is
An input terminal for inputting a horizontal synchronizing signal of an input video signal, 13 is an input terminal for a vertical synchronizing signal, and an input terminal 12
Is connected to the input of the counter 14, and the output of the counter 14 is input to the determination unit 15. Reference numeral 16 is a control unit, which is the judgment unit 1
5, the table 17 is connected, the switching control unit 18 is further connected, and the output of the switching control unit 18 is connected to the switching control terminal 19 of the switch 3.

The operation of the signal adaptive filter processing system having the above configuration will be described below. A video signal having a predetermined frequency band is input to the input unit 1, the horizontal synchronizing signal is input to the terminal 12, and the vertical synchronizing signal is input to the terminal 13. The counter 4 counts the number of horizontal synchronizing signals by the horizontal synchronizing signal input from the terminal 12 from the rising edge of the vertical synchronizing signal input from the terminal 13, for example, and the determination unit 15 determines the counted value. Discriminate,
The frequency band of the input video signal is determined, and the result is input to the control unit 16. The control unit 16 reads out a suitable filter type from the table 17 based on the determination result and outputs it to the switching control unit 18, and the switching control unit 1
Reference numeral 8 outputs a switching signal to the switching control terminal 19 to switch the switching terminal 4 of the switch 3 to connect with a filter suitable for the input video signal.

[0008]

As described above, according to the signal adaptive filter processing method of the present invention, the horizontal synchronizing signal is counted by the counter 4, and the counted value is input by comparing with the judging section. Since the frequency band of the video signal is discriminated and the filter suitable for the input video signal is selected, it is possible to automatically select the suitable filter, and the image quality does not deteriorate due to folding error. Can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram of essential parts of a signal adaptive filter processing device according to the present invention.

[Explanation of symbols]

 1 input section 2 terminal 3 switch 4 terminal 5 terminal 6 filter 7 filter 8 filter 9 filter

Claims (1)

[Claims] 1. A video signal processing circuit having an A / D converter for inputting an analog video signal and performing A / D conversion, and an input section for inputting a video signal having at least two or more kinds of frequency bands; A plurality of filters corresponding to each frequency band, a counter for counting the number of horizontal scanning lines of the input video signal, a table having data for selecting the filter based on the count value of the number of horizontal scanning lines, A signal adaptive filter processing apparatus comprising: a switching unit that selects a filter based on the data, and a switching control unit based on a count value of the counter.