CN102821227A

CN102821227A - Method for determining odd-even field of video signal

Info

Publication number: CN102821227A
Application number: CN2011101553253A
Authority: CN
Inventors: 官志勇
Original assignee: Shanghai Huahong Integrated Circuit Co Ltd
Current assignee: Shanghai Huahong Integrated Circuit Co Ltd
Priority date: 2011-06-10
Filing date: 2011-06-10
Publication date: 2012-12-12
Anticipated expiration: 2031-06-10
Also published as: CN102821227B

Abstract

The invention discloses a method for determining an odd-even field of a video signal, and the method comprises the following steps of determining a valid border of a line synchronization signal and a valid border of a field synchronization signal according to the line synchronization signal and the field synchronization signal in the video signal; measuring a distance from the field synchronization valid border of one field relative to the line synchronization valid border to be adopted as a first displacement; measuring a distance from the field synchronization valid border of the previous field of the measured field relative to the line synchronization valid border of the previous field to be adopted as a second displacement; comparing the difference value which is obtained by subtracting the second displacement from the first displacement with a line distance, determining the field as an even field if the difference value is greater than a threshold value X, and the range of the threshold value X is more than 0 and less than half of the line distance; and determining the field as an odd field if the difference value is less than the threshold value X. The method can be suitable for a standard video signal and a nonstandard video signal, so that the accuracy and adaptability of the method for determining the odd-even field of the video signal can be improved.

Description

A kind of decision method of vision signal parity field

Technical field

The present invention relates to television video signal field.

Background technology

In the initial stage of TV tech development,, do not increase bandwidth simultaneously in order to improve the TV refreshing frequency; Early stage TV has adopted a kind of interleaved technology; The scan line that is about to TV is divided into odd-numbered line and even number line, in the time of strange, only scans odd-numbered line, when the idol field, only scans even number line.

Along with the development of technology, produced the new interlaced scan mode of the concurrent exhibition of signal scanning pattern of lining by line scan.Sequence when the field of importing always is strange, and the scan pattern of current video signal is to line by line scan so.Sequence when the field of importing is that parity field replaces, and the scan pattern of current video signal is interlacing scan so.

Along with video signal digitization; For compatible with former TV tech, also because bandwidth utilization has been optimized in interlacing scan really, digital video signal has kept interleaved scan mode simultaneously; And, defined the parity field of standard according to going synchronously and the relation of the position between the field synchronization.Because multimedia market company is numerous; Technical strength varies; The vision signal of a lot of companies does not satisfy the parity field definition of standard; In other words according to the definition of the parity field of standard, often can't determine when the front court be strange or even on earth, cause the scan pattern that can't judge vision signal.

As shown in Figure 1, as row synchronously (HS), field synchronization (VS) is high effectively the time (low effective situation in like manner), and the rising edge of field synchronization occurs being expert between synchronous high period, when the front court is strange.

As shown in Figure 2, outside synchronous high level appears being expert in the rising edge of field synchronization, when the front court is even.

As shown in Figure 3, deviation hemistich distance between the field synchronization of strange field synchronization and idol field, the A field is strange, the A+1 field is even.

As shown in Figure 4, the rising edge of strange field synchronization occurs being expert between synchronous high period, and the B field is strange, and the B+1 field is strange.

The spacing on the effective edge between two row are synchronous is the distance of a video line.

As shown in Figure 5; Field synchronization has postponed a period of time for a certain reason so that strange the field sync signal with the idol field all drops on row outside the synchronous valid period; Current demand signal criteria of right and wrong vision signal; If with the definition of the parity field of standard, the sequence that can wrong analysis appears on the scene is always to be even, causes and can't infer that interlacing scan still lines by line scan.

Summary of the invention

The technical problem that the present invention will solve provides a kind of decision method of vision signal parity field, can be applicable to vision signal and off-gauge vision signal of standard, improves the accuracy and the applicability of the decision method of vision signal parity field

For solving the problems of the technologies described above, decision method of the present invention may further comprise the steps:

(1) in a vision signal,, field sync signal synchronous according to row confirms that row is synchronous, effective edge of field sync signal;

When row synchronously, field sync signal is high effectively the time, effectively along being rising edge;

When row synchronously, field sync signal is low when effective, effectively along being trailing edge;

(2) record a certain field synchronization effectively along being first displacement effectively synchronously along distance with respect to row;

Last one field synchronization that records this is effective in the edge distance is second displacement with respect to going synchronously effectively;

(3) difference and the row distance that first displacement are deducted second displacement compare, and said difference is more than or equal to a threshold X, judge that this field is an idol, and the span of this threshold X is 0＜X＜1/2 row distance;

Said difference judges that less than threshold X this field is strange.

Said threshold X is 1/4 row distance.

For off-gauge signal, need judge the type of field with respect to the synchronous displacement of row through field synchronization.

As shown in Figure 3, the field synchronization of standard idol field is bigger with respect to capable synchronous displacement, and this displacement is the hemistich distance.

As shown in Figure 4, the field synchronization that standard is strange is very little with respect to capable synchronous displacement, and this displacement is 0.

0 with the gap of hemistich distance, capable of usingly judge parity field.Locking phase judges that for going synchronous displacement greater than waiting threshold X this field is the idol field then and there, and the span of this threshold X scope is 0＜X＜1/2 row distance; Locking phase judges that for going synchronous displacement less than threshold X this field is strange then and there.

The present invention provides the decision method of vision signal parity field, can be applicable to vision signal and off-gauge vision signal of standard, improves the accuracy and the applicability of the decision method of vision signal parity field

Description of drawings

Below in conjunction with accompanying drawing and embodiment the present invention is done further detailed explanation:

Fig. 1 is the strange sketch map of standard.

Fig. 2 is a standard idol sketch map.

Fig. 3 is a standard parity field sketch map.

Fig. 4 is the strange continuously sketch map of standard.

Fig. 5 is a non-standard video signal schematic representation after Fig. 3 exception deferral.

Fig. 6 is the sketch map of one embodiment of the invention.

Reference numeral

HS is that the synchronous VS of row is a field synchronization

A is that A field A+1 is next of A field

B is that B field B+1 is next of B field

M is that M field M+1 is next of M field

T1 is that the second displacement t2 is first displacement.

Embodiment

As shown in Figure 6, in a vision signal, recording the field synchronization rising edge of M+1 field is the first displacement t2 with respect to the synchronous rising edge distance of row; The field synchronization rising edge that records this a last M field is the second displacement t1 with respect to the synchronous rising edge distance of row.

The difference and threshold value 1/4 row distance that the measured first displacement t2 are deducted the second displacement t1 compare, and said difference judges that more than or equal to 1/4 row distance this field is the idol field.The rising edge of M field field synchronization occurs being expert at outside the synchronous high level, and this is an idol, judges accurately.

More than through embodiment and embodiment the present invention has been carried out detailed explanation, but these are not to be construed as limiting the invention.Under the situation that does not break away from the principle of the invention, those skilled in the art also can make many distortion and improvement, and these also should be regarded as protection scope of the present invention.

Claims

1. the decision method of a vision signal parity field is characterized in that, may further comprise the steps:

(3) difference and the row distance that first displacement are deducted second displacement compare, and said difference is greater than a threshold X, judge that this field is an idol, and the span of this threshold X is 0＜X＜1/2 row distance;

Said difference judges that less than threshold X this field is strange.

2. decision method as claimed in claim 1 is characterized in that: said threshold X is 1/4 row distance.