CN100485745C - Method and device for eliminating interference noise contained in signal source - Google Patents

Abstract

The invention relates to a device and a method for eliminating interference noise in a signal source; the method comprises the following steps: generating a digital dithering signal; coding the offset signal and the digital color-transfer signal to generate a color-transfer offset signal; converting the dithering shift signal to an analog dithering shift signal; adding the analog dithering offset signal to the analog image signal to generate a dithering image signal; the dithering image signal is converted into a digital image signal.

Description

Method and device for eliminating interference noise contained in signal source

technical field

The invention relates to a signal processing technology, in particular to a device and method for eliminating interference noise contained in a signal source.

Background technique

At present, most personal computers use a graphics card to convert digital signals into RGB analog signals that are sent to a display (such as a liquid crystal display). Digital signals, however, RGB analog signals may be subject to noise, such as patterning or moving noise, which may be amplified during the analog-to-digital conversion process, resulting in fluctuating noise and possibly ripples on the display effect or other visual effects that are easily noticed by the user, thus greatly reducing the display quality.

Contents of the invention

The technical problem to be solved by the present invention is to provide a device and method for eliminating interference noise contained in a signal source, which uses a dithering method to eliminate interference noise contained in a signal source.

The invention discloses a method for converting an analog image signal into a digital image signal. The steps include: generating a digital dithering signal; encoding the offset signal and the digital dithering signal to generate a dithering offset signal; The color shift signal is converted into an analog dithering shift signal; the analog dithering shift signal is added to the analog image signal to generate a dithering image signal; the dithering image signal is converted into a digital image signal.

To achieve the above objectives, the present invention provides a device for converting an analog image signal into a digital image signal, including: a virtual random sequence generator, a digital-to-analog converter, an adder, and an analog-to-digital converter. The virtual random sequence generator is used to generate digital dither signals; the digital-to-analog converter is used to convert digital dither signals into analog dither signals; the adder is used to generate dither image signals based on analog dither signals and analog image signals ; The analog-to-digital converter is used to convert the dithering image signal into a digital image signal.

In addition, the present invention provides a device for converting an analog image signal into a digital image signal, including: a pseudo-random sequence generator, a scrambler, a digital-to-analog converter, an adder, and an analog-to-digital converter. The virtual random sequence generator is used to generate the digital dithering signal; the scrambler is used to receive the offset signal, and generates a dithering offset signal by encoding it with the digital dithering signal; the digital-to-analog converter is used to convert the dithering offset The signal is converted into an analog dithering offset signal; the adder is used to generate a dithering image signal according to the analog dithering offset signal and the analog image signal; the analog-to-digital converter is used to convert the dithering image signal into a digital image signal.

Moreover, the present invention provides a method for converting an analog image signal into a digital image signal, the steps of which include: generating a digital dithering signal; converting the digital dithering signal into an analog dithering signal; combining the analog dithering signal with the analog The image signals are added to generate a dithering image signal; the dithering image signal is converted into a digital image signal.

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments, but not as a limitation of the present invention.

Description of drawings

FIG. 1 is a flow chart of a method for eliminating interference noise contained in a signal source according to a preferred embodiment of the present invention;

Fig. 2 is the circuit block diagram of the preferred embodiment of the present invention;

Fig. 3 is the circuit block diagram of another preferred embodiment of the present invention;

FIG. 4 is a circuit block diagram of yet another preferred embodiment of the present invention.

Description of figure number:

205～virtual random sequence generator; 210～digital dithering signal;

220～digital-to-analog converter; 230～analog dithering signal;

240～adder; 250～image signal that has eliminated interference signal;

260 ~ analog-to-digital converter;

305～virtual random sequence generator; 310～digital dithering signal;

320～adder; 330～offset signal;

340～dither offset signal; 350～offset digital-to-analog converter;

360～analog dithering offset signal; 370～adder;

380～image signal with interference signal eliminated; 390～analog-to-digital converter;

405～virtual random sequence generator; 410～digital dithering signal;

420～scrambler; 430～dither code signal;

440～dither offset signal; 450～offset digital-to-analog converter;

460～analog dithering offset signal; 470～adder;

480～image signal that has eliminated interference signal; 490～analog-to-digital converter.

Detailed ways

FIG. 1 shows a flowchart of a method for eliminating interference noise contained in a signal source according to a preferred embodiment of the present invention. The process starts from step 100, enters step 110, first generates a digital dithering signal; in step 120, converts the digital dithering signal into an analog dithering signal; then in step 130, adds the analog image signal and the analog dithering signal , to generate a dithering image signal; at step 140, converting the dithering image signal into a digital image signal; finally, at step 150, the flow of the method ends.

Please refer to FIG. 2 which shows a block diagram of an apparatus for eliminating interference noise contained in a signal source according to a preferred embodiment of the present invention. The circuit 200 can be used in a digital display such as a liquid crystal display. Preferably, the circuit 200 can be integrated into a display controller of a digital display to receive an analog image signal Vin and convert it through analog-to-digital conversion. It should be noted that the "image signal" referred to in this manual refers to any image, video or video signal.

As shown in FIG. 2 , the circuit 200 includes: a virtual random sequence generator 205 , a digital-to-analog converter 220 , an adder 240 and an analog-to-digital converter 260 . The circuit 200 receives and processes an analog image signal Vin to generate a digital image signal Dout. The analog image signal Vin may be provided by a host computer, a video tape player, a VCD player, a DVD player, or similar devices, but is transmitted by different signal sources. The analog image signal Vin may be subject to noise interference, such as: patterned or mobile noise, this interference noise may be amplified during the analog-to-digital conversion process due to the effect of quantization gain. Therefore, the converted analog image signal The digital image signal Dout of the digital image signal will have interference noise, and fluctuate noise will be generated on the digital display.

According to the present invention, the virtual random sequence generator 205 is used to generate the digital dithering signal 210, so the digital dithering signal 210 is generated by the virtual random sequence generator 205 in the form of a virtual random sequence, and this virtual random sequence is semi-random (semi-random) random) sequence, that is, the length of the sequence is arbitrary, which meets the requirement of randomness, but the whole set of sequences will repeat irregularly. For the detailed circuit of the virtual random sequence generator, please refer to the article "Pseudo Noise Sequence for Engineers" published by R.N. Mutagi in April 1996 in "Journal of Electronic Communication Engineering" on pages 79-87. & Communication Engineering Journal, April 1996, pp.79-87). In the application of the controller of the liquid crystal display, the length of the pseudo-random sequence will be greater than the total number of pixels of the image display frame.

The digital-to-analog converter 220 is connected to the virtual random sequence generator 205 and the adder 240 respectively, and the digital-to-analog converter 220 is used to convert the digital dithering signal 210 into a nearly random analog dithering signal 230, and the analog dithering signal 230 Received by the adder 240, therefore, the adder 240 introduces the analog dithering signal 230 into the analog image signal Vin, since the digital dithering signal 210 is a semi-random sequence, the analog image can be eliminated by adding the analog dithering signal 230 The interference signal contained in the signal Vin makes the adder 240 generate the image signal 250 from which the interference signal has been eliminated, and the image signal 250 from which the interference signal has been eliminated is sent to the analog-to-digital converter 260 for further signal processing.

The analog-to-digital converter 260 receives the image signal 250 from which the interference signal has been eliminated, and converts it into a corresponding digital image signal Dout, because the interference noise is eliminated by adding the analog image signal Vin to the analog dithering signal 230 , the interference noise is reduced by converting the digital image signal Dout obtained from the image signal 250 from which the interference signal has been eliminated.

Please refer to FIG. 3 , which is a block diagram of a circuit 300 according to another preferred embodiment of the present invention. As shown in FIG. 3 , the circuit 300 includes: a pseudo random sequence generator 305 , an adder 320 , an offset digital-to-analog converter 350 , an adder 370 and an analog-to-digital converter 390 . An offset DAC 350 exists in the display controller to process the offset signal 330; in this embodiment, the DAC 350 is used to process the offset and dithering signals in a low-cost manner.

The microprocessor generates the offset signal 330 according to the brightness adjustment made by the user. For example, the offset signal 330 is an eight-bit signal OFFSET[7:0], and the adder is used to combine the offset signal 330 with the pseudo random sequence The digital dithering signals 310 generated by the generator 305 are summed to generate a dithering offset signal 340 .

The offset digital-to-analog converter 350 is used to convert the dithering offset signal 340 into a nearly random analog dithering offset signal 360, and the analog dithering offset signal 360 is received by the adder 370. Therefore, the adder 370 introduces the analog dithering offset signal 360 into the analog image signal Vin. Since the digital dithering signal 340 is a semi-random sequence, the interference signal contained in the analog image signal Vin can be eliminated by adding the analog dithering offset signal 360, so that The adder 370 generates the image signal 380 from which the interference signal has been eliminated, and the image signal 380 from which the interference signal has been eliminated is sent to the analog-to-digital converter 390 for further signal processing.

The analog-to-digital converter 390 receives the image signal 380 from which the interference signal has been eliminated, and converts it into a corresponding digital image signal Dout, since the interference has been eliminated by adding the analog image signal Vin to the analog dithering offset signal 360 Noise elimination, the digital image signal Dout obtained by converting the image signal 380 from which the interference signal has been eliminated has reduced interference noise.

Please refer to FIG. 4 , which is a block diagram of a circuit 400 according to another preferred embodiment of the present invention. As shown in FIG. 4 , the circuit 400 includes: a pseudo-random sequence generator 405 , a code scrambler 420 , an offset digital-to-analog converter 450 , an adder 470 and an analog-to-digital converter 490 . An offset DAC 450 exists in the display controller to process the offset signal OFFSET; in this embodiment, the DAC 450 is used to process the offset and dithering signals in a low-cost manner.

The microprocessor generates an offset signal OFFSET according to the brightness adjustment made by the user. For example, the offset signal OFFSET is an eight-bit signal OFFSET[7:0], and one or two least significant bits ( least significant bit, LSB) to the scrambler 420, and the scrambler 420 encodes it with the digital dithering signal 410 generated by the virtual random sequence generator 405, as shown in FIG. 4 , the scrambler 420 encodes the two The least significant bits OFFSET[1:0] are coded with the digital dithering signal 410 to generate a dithering coded signal 430, represented by DO[1:0]. The dithering coded signal DO[1:0] 430 and the offset The signals OFFSET[7:2] are combined into a dithering offset signal 440, represented by DO[7:0].

The offset digital-to-analog converter 450 is used to convert the dithering offset signal 440 into a nearly random analog dithering offset signal 460, and the analog dithering offset signal 460 is received by the adder 470. Therefore, the adder 470 introduces the analog dithering offset signal 460 into the analog image signal Vin. Since the digital dithering signal 410 is a semi-random sequence, the interference signal contained in the analog image signal Vin can be eliminated by adding the analog dithering offset signal 460, so that The adder 470 generates the image signal 480 from which the interference signal has been eliminated, and the image signal 480 from which the interference signal has been eliminated is sent to the analog-to-digital converter 490 for further signal processing.

The analog-to-digital converter 490 receives the image signal 480 from which the interference signal has been eliminated, and converts it into a corresponding digital image signal Dout, because by adding the analog image signal Vin to the analog dithering offset signal 460, the interference Noise elimination, the digital image signal Dout obtained by converting the image signal 480 from which the interference signal has been eliminated has reduced interference noise. In addition, the circuit shown in Figure 4 can solve the non-linear problem of DAC by limiting the effect of pseudo-random sequence to the least significant bit.

Certainly, the present invention also can have other multiple embodiments, without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention, but these corresponding Changes and deformations should belong to the scope of protection of the appended claims of the present invention.

Claims (9)

1, a kind of erasure signal source includes the method for interference noise, in order to convert an analog picture signal to a data image signal, it is characterized in that, comprises the following steps:

Produce a numeral and pass chrominance signal;

One shifted signal and this numeral are passed chrominance signal stir sign indicating number and handle, produce a numeral and pass the color shift signal;

This numeral is passed the color shift conversion of signals becomes a simulation to pass the color shift signal;

This analog picture signal and this simulation are passed the color shift signal plus, pass the color image signal to produce one; And

This is passed the color image conversion of signals become this data image signal.

2, a kind of erasure signal source includes the device of interference noise,, it is characterized in that this device comprises in order to convert an analog picture signal to a data image signal:

One pseudorandom sequence generator is passed chrominance signal in order to produce a numeral;

One digital analog converter converts a simulation to and passs chrominance signal in order to this numeral is passed chrominance signal;

One adds and grows up to be a useful person, and produces one and passs the color image signal in order to pass chrominance signal and this analog picture signal according to this simulation; And

One analog-digital converter becomes this data image signal in order to this is passed the color image conversion of signals.

3, device as claimed in claim 2 is characterized in that, this adds to grow up to be a useful person passs the color image signal in order to this analog picture signal and this simulation are passed the chrominance signal addition and produced this.

4, a kind of erasure signal source includes the device of interference noise,, it is characterized in that this device comprises in order to convert an analog picture signal to a data image signal:

One pseudorandom sequence generator is passed chrominance signal in order to produce a numeral;

One stirs a yard device, in order to receiving a shifted signal, encodes by this shifted signal and this numeral are passed chrominance signal, produces a numeral and passs the color shift signal;

One digital analog converter becomes simulation to pass the color shift signal in order to this numeral is passed the color shift conversion of signals;

One adds and grows up to be a useful person, and produces one and passs the color image signal in order to pass color shift signal and this analog picture signal according to this simulation; And

One analog-digital converter becomes this data image signal in order to this is passed the color image conversion of signals.

5, device as claimed in claim 4 is characterized in that, this adds grows up to be a useful person in order to this analog picture signal and this simulation are passed the color shift signal plus.

6, device as claimed in claim 4 is characterized in that, this stirs yard device and encodes in order at least one Least Significant Bit in the middle of this shifted signal and this numeral are passed chrominance signal.

7, a kind of erasure signal source includes the device of interference noise,, it is characterized in that this device comprises in order to convert an analog picture signal to a data image signal:

One pseudorandom sequence generator is passed chrominance signal in order to produce a numeral;

One totalizer in order to receive a shifted signal, by this shifted signal and this numeral are passed the chrominance signal addition, produces one and passs the color shift signal;

One digital analog converter becomes simulation to pass the color shift signal in order to this is passed the color shift conversion of signals;

One adds and grows up to be a useful person, and produces one and passs the color image signal in order to pass color shift signal and this analog picture signal according to this simulation; And

One analog-digital converter becomes this data image signal in order to this is passed the color image conversion of signals.

8, device as claimed in claim 7 is characterized in that, this adds grows up to be a useful person in order to this analog picture signal and this simulation are passed the color shift signal plus.

9, a kind of erasure signal source includes the method for interference noise,, it is characterized in that this method comprises the following steps: in order to convert an analog picture signal to a data image signal

Produce a numeral and pass chrominance signal;

This numeral is passed chrominance signal to be converted a simulation to and passs chrominance signal;

This analog picture signal and this simulation are passed the chrominance signal addition, pass the color image signal to produce one; And

This is passed the color image conversion of signals become this data image signal.

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