CN105574881A - Vga boundary detection technology - Google Patents

Abstract

The invention relates to a VGA boundary detection technology. In the process of VGA video transmission or processing, SYNC signals and DATA are shifted, and a displayed image is shifted during direct display. By employing the technology, the shifts of the displayed image in the horizontal direction, in the vertical direction, and in the standard position are determined, the time sequence for displaying the image is adjusted in a subsequent processing module, and the finally displayed image is returned to the central position again. The technology includes following steps: hardware detects the boundary of the image; and the final position of the displayed image is adjusted by employing the result of boundary detection.

Description

VGA bound test technology

Technical field

The present invention relates to video images detection field, particularly relate to a kind of VGA bound test technology.

Background technology

Current VGA video receiver is when carrying out Video processing, there is the problem that offseting appears in Timing (line synchronizing signal HSYNC and field sync signal VSYNC) and Data (Video effective video data) in transmission or processing procedure, and need to carry out picture position correction to final output image.Although the ultimate principle of each VGA receiving equipment Boundary Detection is roughly the same, wherein the method for specific implementation is different, and the accuracy rate of Boundary Detection can form difference, and the position causing final image to show is also each variant.

The bound test technology of VGA is all generally the different positions removing to determine video boundaries that are interval by Black and the rgb value of the interval pixel of ActiveVideo, but this method also has certain limitation, the image that such as a width is entirely black, Black is interval identical with the rgb value of the interval pixel of ActiveVideo, and ultimate bound detects can failure.VGA bound test technology of the present invention, for these situations, judges again to final result, filters out similar special circumstances and does further process.

Summary of the invention

The present invention proposes a kind of VGA bound test technology, and the method is achieved like this:

VGA bound test technology uses the border of hardware detection Video: horizontal direction reference position Hstart, horizontal direction end position Hstop, vertical direction reference position Vstart, vertical direction end position Vstop.Judge now whether Image display position departs from standard value according to the result detected, and the position of further adjustment output image, make output image show more information and position is placed in the middle.

VGA signal is the data of effective Video the transmission of ActiveVideo interval, and in the transmission of Black interval is black data (values of corresponding R, G, B be all 0 or very little value).

In the process of VGA transmission of video or process, SYNC signal and DATA there occurs skew, and when directly showing, the image of display also can offset.Adopt VGA bound test technology, the skew of the image level direction determining now to show, vertical direction and normal place, then adjusts the sequential of image display, makes the image of final display come back to position placed in the middle in follow-up processing module.

VGA bound test technology of the present invention, it comprises the following steps:

S1: the border of hardware detection image;

Utilize the interval characteristic for pure black image (rgb value should be 0) of the BLANK of video, arrange threshold value, all pixels of the single Frame of traversal Video, find out the line number that valid pixel occurs at first, are horizontal direction border reference position (Hstart); The row number occurred at first of valid pixel, are vertical direction border reference position (Vstart); The line number of the last appearance of valid pixel, is horizontal direction border reference position (Hstop); The row number of the last appearance of valid pixel, are vertical direction border reference position (Vstop);

In order to make the result of hardware detection more accurate, hardware detection has carried out three times and has retained result further judging.Three results for Hstart, Hstop, Vstart, Vstop:

When the result of twice detection is the same, just using obtain result as the net result of this parameter;

When the result of three detections is all different, the result just detected third time is as the net result of this parameter;

S2: the position utilizing the result adjustment final display image of Boundary Detection;

Obtain the boundary position (Hstart of hardware detection, Hstop, Vstart, Vstop) after, boundary position (Hstart_std, the Hstop_std of video mode standard therewith, Vstart_std, Vstop_std) carry out contrast to judge, then adjust the sequential of output, determine the region of final display.

The advantage that the present invention has and good effect are: the border that VGA effective video can be detected more accurately, and the follow-up further judgement process to border testing result, the inaccurate border result that some particular image cause can be filtered out, after judging, adjust the sequential of output video, under the prerequisite of reservation image information as much as possible, make the image display of output placed in the middle.

Accompanying drawing explanation

Fig. 1 is VGA signal timing diagram;

Fig. 2 be VGA video boundaries detect Active value identical with standard value time comparison diagram;

Fig. 3 is that VGA video boundaries detects comparison diagram when Active value is greater than standard value;

Fig. 4 is that VGA video boundaries detects comparison diagram when Active value is less than standard value.

Embodiment

In order to make object of the present invention, technical scheme and advantage clearly understand, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.

VGA bound test technology performing step of the present invention comprises the border of hardware detection image, utilizes the position of the result adjustment final display image of Boundary Detection.Wherein utilize the adjustment of the result of Boundary Detection finally to show picture position, concrete methods of realizing comprises:

1, as Hstart<7 or Hstop<7, the image level position of final display uses the valid pixel of the standard value Hstart_std(video mode horizontal direction standard of this pattern to count), the valid pixel of Hstop_std(video mode vertical direction standard is counted);

2, as Vstart<5 or Vstop <5, the image upright position of final display uses the standard value Vstart_std of this pattern, Vstop_std;

This detection preferred is to filter some extreme situations (as all black picture etc.);

3, as (Hstop-Hstart)=(Hstop_std-Hstart_std), namely the H direction Active value detected is consistent with standard level direction effective pixel points, the image level position of final display uses the result Hstart of Boundary Detection, Hstop;

4, as (Vstop-Vstart)=(Vstop_std-Vstart_std), namely the V direction Active value detected is consistent with standard vertical direction effective pixel points, the image level position of final display uses the result Vstart of Boundary Detection, Vstop;

5, as (Hstop-Hstart) > (Hstop_std-Hstart_std), the H direction Active value namely detected is greater than standard level direction effective pixel points;

With reference to first three kind situation of Fig. 3, final display image level reference position uses the result Hstart of Boundary Detection, and the final image level end position that shows uses reference position value to add H direction standard Active value Hstart+Hactive_std;

With reference to the 4th kind of situation of Fig. 3, final display image shows between two parties, horizontal reference position is Hstart+ ((Hstop-Hstart)-(Hstop_std-Hstart_std))/2, and final display image level end position uses reference position value to add H direction standard Active value Hstart+ ((Hstop-Hstart)-(Hstop_std-Hstart_std)/2)+Hactive_std;

6, as (Vstop-Vstart) > (Vstop_std-Vstart_std), the V direction Active value namely detected is greater than standard vertical direction effective pixel points;

With reference to first three kind situation of Fig. 3, final display image vertical starting position uses the result Vstart of Boundary Detection, and the final vertical end position of image that shows uses reference position value to add V direction standard Active value Vstart+Vactive_std;

With reference to the 4th kind of situation of Fig. 3, final display image shows between two parties, vertical starting position is Vstart+ ((Vstop-Vstart)-(Vstop_std-Vstart_std))/2, and the vertical end position of final display image uses reference position value to add V direction standard Active value (Vstart+ ((Vstop-Vstart)-(Vstop_std-Vstart_std))/2)+Vactive_std;

7, as (Hstop-Hstart) < (Hstop_std-Hstart_std), the H direction Active value namely detected is less than standard level direction effective pixel points;

With reference to the 1st of Fig. 4,2 kinds of situations, final display image level reference position uses the result Hstart of Boundary Detection, and final display image level end position uses reference position value to add H direction standard Active value Hstart+Hactive_std;

With reference to the 3rd of Fig. 4,4 kinds of situations, final display image level end position uses the result Hstop of Boundary Detection, and final display image level reference position uses end position value to deduct H direction standard Active value Hstop-Hactive_std;

With reference to the 5th kind of situation of Fig. 4, final display image level reference position uses the standard value Hstart_std of this pattern, and final display image level end position uses reference position value to add H direction standard Active value Hstart_std+Hactive_std;

8, as (Vstop-Vstart) < (Vstop_std-Vstart_std), the V direction Active value namely detected is less than standard vertical direction effective pixel points;

With reference to the 1st of Fig. 4,2 kinds of situations, final display image vertical starting position uses the result Vstart of Boundary Detection, and the vertical end position of final display image uses reference position value to add V direction standard Active value Vstart+Vactive_std;

With reference to the 3rd of Fig. 4,4 kinds of situations, the vertical end position of final display image uses the result Vstop of Boundary Detection, and final display image vertical starting position uses end position value to deduct V direction standard Active value Vstop-Vactive_std;

With reference to the 5th kind of situation of Fig. 4, final display image vertical starting position uses the standard value Vstart_std of this pattern, and the vertical end position of final display image uses reference position value to add V direction standard Active value Vstart_std+Vactive_std.

Claims (1)

1. a VGA bound test technology, is characterized in that, comprises the following steps:

S1: the border of hardware detection image;

Utilize the interval characteristic for pure black image (rgb value should be 0) of the BLANK of video, arrange threshold value, all pixels of the single Frame of traversal Video, find out the line number that valid pixel occurs at first, are horizontal direction border reference position (Hstart); The row number occurred at first of valid pixel, are vertical direction border reference position (Vstart); The line number of the last appearance of valid pixel, is horizontal direction border reference position (Hstop); The row number of the last appearance of valid pixel, are vertical direction border reference position (Vstop);

In order to make the result of hardware detection more accurate, hardware detection has carried out three times and has retained result further judging;

Three results for Hstart, Hstop, Vstart, Vstop:

When the result of twice detection is the same, just using obtain result as the net result of this parameter;

When the result of three detections is all different, the result just detected third time is as the net result of this parameter;

S2: the position utilizing the result adjustment final display image of Boundary Detection;

Obtain the boundary position (Hstart of hardware detection, Hstop, Vstart, Vstop) after, boundary position (Hstart_std, the Hstop_std of video mode standard therewith, Vstart_std, Vstop_std) carry out contrast to judge, then adjust the sequential of output, determine the region of final display.