VGA video signal pattern recognition method

Abstract

The invention discloses a VGA (Video Graphics Array) video signal pattern recognition method. The method comprises the following steps: measuring the horizontal synchronizing signal and the vertical synchronizing signal of a VGA signal through hardware to obtain five signal parameters, namely HPer, VPer, VTotal, HPolarity and VPolarity; meanwhile, adding three parameters, namely HPolarity (Horizontal synchronous polarity), VPolarity (Vertical synchronous polarity) and ValidSyncPolarity (Polarity valid flag) in a standard VGA pattern list; and carrying out finding and matching on the obtained five signal parameters, namely HPer, VPer, VTotal, HPolarity and VPolarity and the parameters in the standard pattern list, so as to obtain an accurate video signal pattern. According to the invention, a traditional VGA video signal pattern recognition method is improved, so that the accuracy rate of VGA video signal pattern recognition is increased, and the display effect is improved after the VGA video signal is digitally processed.

Description

technical field [0001] The invention relates to the technical field of acquisition of analog video signals and digital processing of analog video signals, in particular to a VGA video signal pattern recognition method. . Background technique [0002] When digitizing the VGA video signal, an accurate identification mode is required, and the mode of a VGA video signal can be determined by the line frequency (HPer), the field frequency (VPer), the total number of lines of each image (VTotal), and the data of each line. The four signal parameters of the total number of pixels (HTotal) are uniquely determined, that is, when these four parameters are determined, the mode of the VGA video signal is determined. [0003] In the prior art, it is mainly to directly measure the HPer, VPer and VTotal three signal parameters of the VGA video signal by hardware, and use these three parameters to find the VGA video signal mode consistent with its parameters or the closest in a standard mod...

AI Technical Summary

Problems solved by technology

But, adopt this kind of method in the prior art, there will be these defects in application: because only 3 signal parameters can be obtained directly through hardware measurement in the 4 signal parameters of VGA video signal, so may not recognize part VGA video mode Accurate, it is recognized as a VGA video mode similar to it, which will lead to sampling data errors, and finally lead to unsatisfactory display effects

The reason for this kind of error is that there are some approximate modes in the standard VGA video mode. The so-called approximate mode means that their HPer, VPer and VTotal are very close, but there is a big difference in HTotal, and the output timing of different graphics cards will be slightly different. These three signal parameters obtained directly by hardware measurement may be recognized as similar modes when looking up in the standard VGA mode table

In many approximate modes, their timing parameters are very different, such as 1280*76860Hz and 1366*76860Hz. The HPer, VPer, and VTotal of these two modes are very close, but the front shoulder HFrontPorch and the back shoulder HBackPorch in the horizontal direction , the synchronization width HSyncWidth, the front shoulder VFrontPorch, the back shoulder VBackPorch, and the synchronization width VSyncWidth in the vertical direction have a large difference, so the conventional method cannot identify the VGA video signal mode very accurately, and the wrong mode recognition will lead to the collection and processing of the video signal. Handle an error

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