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Chroma synchronizing method and device of composite video signal

A composite video signal and signal technology, applied in the direction of color burst, generation/insertion of color burst signal, color TV parts, etc., can solve the problems of color tone gradient and inaccurate chroma synchronization, etc., to improve accuracy, Frequency compensation reduction to resolve the effect of tone gradients

Active Publication Date: 2016-04-06
ZHEJIANG DAHUA TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0010] The embodiment of the present invention provides a method and device for chromaticity synchronization of a composite video signal, which is used to solve the problem that the color tone gradient from left to right often appears in the generated picture due to the inaccurate chromaticity synchronization.

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  • Chroma synchronizing method and device of composite video signal
  • Chroma synchronizing method and device of composite video signal
  • Chroma synchronizing method and device of composite video signal

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Embodiment 1

[0033] Such as figure 2 As shown, it is a schematic flow chart of the method for chroma synchronization of the composite video signal in Embodiment 1 of the present invention, and the method for chroma synchronization of the composite video signal may include the following steps:

[0034] Step 201: The signal receiving end performs quadrature down-conversion on the received color burst signal of the current line, and obtains the quadrature component signal and the in-phase component signal of the color burst signal within the preset sampling interval of the current line.

[0035] For example, after discrete sampling, the time-domain diagram of the chrominance signal and color burst signal of the current row is as follows image 3 Shown: in image 3 Among them, 301 represents a color burst signal, wherein the color burst signal between point A and point B represents a preset sampling interval; 302 represents a chrominance signal.

[0036] Step 202: Perform low-pass filtering o...

Embodiment 2

[0100] Based on the same inventive concept, the embodiment of the present invention also provides a device for chroma synchronization of a composite video signal, such as Figure 8 shown, including:

[0101] The down-conversion module 801 is configured to perform quadrature down-conversion on the received color burst signal of the current line, and obtain the quadrature component signal and the in-phase component signal of the color burst signal in the preset sampling interval of the current line;

[0102] The baseband signal phase difference calculation module 802 is used to perform low-pass filtering on the quadrature component signal and the in-phase component signal respectively to obtain the filtered quadrature component signal and the filtered in-phase component signal; and calculate the filtered quadrature component signal and the filtered Baseband signal phase difference between back in-phase component signals;

[0103] The compensation module 803 is used to calculate...

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Abstract

The invention discloses a chroma synchronizing method and device of a composite video signal. The solution of the invention comprises: carrying out orthogonal down-conversion to a colour synchronizing signal in a preset sampling interval, obtaining a filtered orthogonal component signal and a filtered cophase component signal, carrying out phase discrimination to the two component signals so as to obtain a baseband signal phase difference, fitting a calculation model taking the baseband signal phase difference of the sampling point as the known quantity, and the estimation value of the carrier wave phase difference of an assigned reference point and the estimation value of the carrier wave frequency difference as unknown quantities, calculating the two estimation values, carrying out phase compensation and frequency compensation to the local carrier wave of the current line according to the calculating result. The chroma synchronizing method provided by the embodiment of the invention realizes phase compensation to the local carrier wave, also realizes frequency compensation to the local carrier wave, reduces the linear phase errors, solves the problem that the tonality of the colour in the picture varies gradually from the left to the right, and improves chroma synchronizing accuracy.

Description

technical field [0001] The invention relates to the technical field of video signal processing, in particular to a method and device for chroma synchronization of a composite video signal. Background technique [0002] Composite video signals usually include chrominance signals, color burst signals, luminance signals, and line and field synchronization information. Among them, the chrominance signal is generated by the signal transmitter after modulating the color difference signal carrying the color information with the subcarrier of the transmitter. In order for the signal receiver to correctly demodulate the chrominance signal to display the video image, the signal receiver must generate a A local carrier with the same frequency and phase as the subcarrier at the transmitter. The color burst signal in the composite video signal is the signal receiver to recover the local carrier to achieve color synchronization. [0003] If the phase of the local carrier recovered by th...

Claims

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Application Information

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IPC IPC(8): H04N9/44H04N9/45H04N9/455
CPCH04N9/44H04N9/45H04N9/455
Inventor 华杰吕炳赟杨银昌蒋金冰朱竹青
Owner ZHEJIANG DAHUA TECH CO LTD
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