CN102055990A - Method and device for detecting PAL type video signal subcarrier phase conversion - Google Patents
Method and device for detecting PAL type video signal subcarrier phase conversion Download PDFInfo
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Abstract
The invention discloses a method for detecting phase alternation line (PAL) type video signal subcarrier phase conversion, which comprises the following steps of: acquiring initial identification signals of a PAL row and a national television system committee (NTSC) row; acquiring local identification signals of the PAL row and the NTSC row; and comparing the local identification signals with the initial identification signals, and outputting identification signals of the PAL row and the NTSC row according to the comparison result. A device for detecting the PAL type video signal subcarrier phase conversion comprises an initial identification module for acquiring the initial identification signals of the PAL row and the NTSC row, a local signal generating circuit, a statistical comparison module and a logic control module. The method and the device for detecting the PAL type video signal subcarrier phase conversion finally output the local generated signals and have stable output results.
Description
Technical field
The invention belongs to TV technology, relate to a kind of detection method and device of pal video signal subcarrier phase conversion.
Background technology
PAL (Phase Alternation Line, phase place is alternation line by line) standard is a kind of in the simulation color television system, with other two kinds of simulation color television systems--SECAM (SequentialCouleur a Memoire, order transmits colored and storage), NTSC (National TelevisionSystem Committee, the international television standard committee) and claim the simulation color TV three big standards.TSC-system is nineteen fifty-three a kind of compatible color television standard of succeeding in developing of the U.S..By the formation characteristics of carrier chrominance signal, this standard is called quadrature amplitude balance system again.In order to alleviate the phase mutual interference between luminance signal and the carrier chrominance signal, common carrier chrominance signal is in the high-end sub-carrier modulation of video passband by color difference signal to frequency and forms.The main Energy distribution of luminance signal is at the low side of passband, and the main energy of carrier chrominance signal then is distributed in high-end.Positive and negative peak point constantly appears in the carrier chrominance signal of the higher-order of oscillation, thereby can form the photoelectric interference of bright spot, dim spot on video screen.In order to reduce this interference, TSC-system has adopted balanced amplitude modulation and frequency interlace principle.The former can slacken the luminous point interference intensity, and the latter can realize the effect of disappearing mutually of the luminous point between adjacent lines, the opposite field.
In order to transmit chrominance information with the subcarrier of single-frequency, the NTSC carrier chrominance signal is that the subcarrier balance amplitude modulation of two same frequencys of 0 ° and 90 ° mixes again to initial phase respectively by two color difference signals.What adopt usually is blue (B-Y), red color difference signal (R-Y), and its carrier chrominance signal can be expressed as: C=0.455 (B-Y) sin2 π f
SCT+0.812 (R-Y) cos2 π f
SCT, wherein f
SCBe the frequency of color sub-carrier, f
SC=3.579545...MHz ± 10Hz.
In TSC-system, there is phase sensitivity, i.e. the phase distortion of carrier chrominance signal has a significant effect to reappearing colored tone.In order to overcome the phase sensitivity of TSC-system, went out a kind of Phase Alternation Line system at German Research in 1962.By the characteristics of carrier chrominance signal, Phase Alternation Line system claims line-by-line inversion quadrature amplitude balance system again.The maximum difference of Phase Alternation Line system and TSC-system just is in the line-by-line inversion that the pal chroma signal still is the quadrature amplitude balance signal, and just red color difference component is carried out the line-by-line inversion processing.Its carrier chrominance signal can be expressed as: C=0.493 (B-Y) sin2 π f
SCT ± 0.877 (R-Y) cos2 π f
SCT, wherein f
SCBe the frequency of color sub-carrier, f
SC=4.43361875MHz ± 1Hz.
In the PAL chrominance subcarrier signal of adjacent two row, there are delegation and NTSC chrominance carrier identical, claim that it is that NTSC is capable; The chrominance carrier phase place of another row is reindexing then, claims that it is that PAL is capable.Owing to separating timing, have one with the color sub-carrier component with the local subcarrier of homophase frequently, therefore, when coding, burst signal of special generation transmits the frequency and the phase information of the required subcarrier of demodulation, the synchronous black-out intervals of being expert at transmits this signal, comprises the subcarrier in 8 to 10 cycles approximately.
For making the correct demodulated chrominance signal of PAL colour TV system receiver, exercise usefulness-cos2 π f at PAL
SCT, exercise usefulness+cos2 π f at NTSC
SCThe t subcarrier just must transmit a burst signal that phase place changes line by line, and phase information is as the capable and capable identification signal of NTSC of identification PAL thus.The phase place of burst signal is 135 ° of NTSC behaviors, and capable at PAL is 225 ° then, has the rule of swing ± 90 degree line by line, therefore also claims swinging-burst.The burst signal of the adjacent triplex row of Phase Alternation Line system as shown in Figure 1.
From above-mentioned information, we can know that in the demodulating process of pal chroma signal PAL is capable and that NTSC is capable, and identification is important link.Existing P AL is capable with the method capable identification of NTSC to be mostly, utilizes the phase relation of the adjacent lines burst signal shown in Fig. 1, if current line burst signal and previous row homophase, then current behavior PAL is capable; If current line burst signal and previous row are anti-phase, then current behavior NTSC is capable.
Existing implementation is called existing PAL-Switch scheme, usually have following several: first kind of scheme as shown in Figure 2, according to the corresponding sampling point symbol of adjacent two circumstances in which people get things ready for a trip synchronizing signals, get one section burst signal (as N point, N gets 16-64, is preferably 32), the statistics current line is different number with the corresponding sampling point symbol of previous row burst signal, if symbol be different number less than first thresholding, then to be identified as PAL capable for current line; If symbol be different number greater than second thresholding (greater than first thresholding), then to be identified as NTSC capable for current line; If symbol is that different number (comprises the first threshold and second threshold value) between the first threshold and second threshold value, and then current line is identical with before interlaced type.Second kind of scheme as shown in Figure 3, (as N point, N gets 16-64 to get one section burst signal, be preferably 32), the data of current line taken point and the data of previous row are done difference, calculate the average absolute of this difference again, if mean value is less than certain thresholding, then to be identified as PAL capable for current line; If mean value is more than or equal to certain thresholding, then to be identified as NTSC capable for current line.The third scheme as shown in Figure 4, get one section burst signal (as N point), the phase place of the data of the data of current line taken point and previous row is made comparisons, ask the average absolute of phase difference, if mean value is less than certain thresholding, then to be identified as PAL capable for current line; If mean value is more than or equal to certain thresholding, then to be identified as NTSC capable for current line.
These existing PAL-Switch schemes are analyzed, find more stable in signal source or situation that interference ratio is less under, it is capable and NTSC is capable correctly to identify PAL basically; But, just can not discern fully when big (being lower than 50dBu) in signal less stable or noise ratio, thereby cause the thread inverse striped of appearance in the coloured image that final decoding comes out as the RF radiofrequency signal.
Summary of the invention
The technical issues that need to address of the present invention are when having the conversion of PAL-Switch scheme detection pal video signal subcarrier phase now, under jitter or the big situation of noise, and the test result instability.
In order to solve the problems of the technologies described above, the invention provides a kind of detection method of pal video signal subcarrier phase conversion, may further comprise the steps: a) obtain the initial identification signal that PAL is capable, NTSC is capable; B) obtain the id signal that local PAL is capable, NTSC is capable; C) described local id signal and initial identification signal are relatively exported capable, the capable identification signal of NTSC of PAL according to comparative result.
Wherein step a) comprises: a
11) obtain the sampling point of one section burst signal of current line and lastrow; a
12) number of opposite in sign of the corresponding sampling point of burst signal of statistics described current line and lastrow; a
13) thresholding of described statistics and setting is compared, discern the type of current line according to the result.
Optionally, step a
11) comprising: be benchmark with the line synchronizing signal, get the burst signal sample value at burst signal correspondence position uplifting window.
Optionally, step a
12) comprising: the corresponding sampling point of the burst signal of described current line and lastrow is got XOR; It to XOR 1 result count.
Optionally, step a
13) comprising: setting thresholding T1, T2 (T1＜T2); With described step a
12) in statistics and thresholding relatively, if described statistics＜T1, then current line is that PAL is capable; If described statistics＞T2, then current line is that NTSC is capable; If T1≤described statistics≤T2, then current line is identical with before interlaced type.
Step a) can adopt second kind of scheme, comprising: a
21) obtain one section burst signal of current line and lastrow; a
22) described current line and lastrow burst signal are done difference, and calculate the average absolute of this difference; a
23) thresholding of described mean value and setting is compared, discern the type of current line according to the result.
Optionally, step a
21) comprising: be benchmark with the line synchronizing signal, get the burst signal sample value at burst signal correspondence position uplifting window.
Optionally, step a
23) comprising: set thresholding T3, with step a
22) in mean value with the thresholding T3 that sets relatively, if mean value less than thresholding T3, then to be identified as PAL capable for current line; If mean value is more than or equal to thresholding T3, then to be identified as NTSC capable for current line.
Step a) can also adopt the third scheme, comprising: a
31) obtain one section burst signal of current line and lastrow; a
32) ask the phase difference of the burst signal of the burst signal of described current line and lastrow, ask this phase difference average absolute; a
33) thresholding of described mean value and setting is compared, discern the type of current line according to the result.
Optionally, step a
31) comprising: be benchmark with the line synchronizing signal, get the burst signal sample value at burst signal correspondence position uplifting window.
Optionally, step a
33) comprising: set thresholding T4, with step a
32) in mean value with the thresholding T4 that sets relatively, if mean value less than thresholding T4, then to be identified as PAL capable for current line; If mean value is more than or equal to thresholding T4, then to be identified as NTSC capable for current line.
Optionally, described local id signal and initial identification signal are the signal of upset line by line.
Optionally, step C) comprising: set a threshold value M, described local id signal is above opposite with initial identification signal continuous N row, with local id signal upset output, otherwise directly exports local id signal;
Optionally, described threshold value M span is 16-32.
The present invention also provides a kind of checkout gear of pal video signal subcarrier phase conversion, comprise the preliminary identification module that obtains the initial identification signal that PAL is capable, NTSC is capable, it is characterized in that, described checkout gear also comprises: local signal generation circuit produces the id signal that local PAL is capable, NTSC is capable; The statistical comparison module, more described local id signal and described initial identification signal; Logic control module, the output of, NTSC line flag signal capable according to the comparative result of described statistical comparison module control local signal generation circuit PAL.
Optionally, described preliminary identification module comprises: acquisition module, obtain the sampling point of one section burst signal of current line and lastrow; The computing statistical module, the number of opposite in sign of adding up the corresponding sampling point of burst signal of described current line and lastrow; The first threshold module is set and storage threshold; Comparing unit, with the threshold ratio of the statistics of described computing statistical module and described first threshold module settings, and the output identification signal.Described computing statistical module comprises: the XOR unit, current line is got XOR with the corresponding sampling point of the burst signal of lastrow; Counter is 1 counting to the XOR result.The threshold value of described first threshold module settings is T1, T2, T1＜T2.Described comparing unit is when described statistics＜T1, and the output current line is that PAL is capable; Described statistics＞T2, the output current line is that NTSC is capable; T1≤described statistics≤T2, the output current line is identical with before interlaced type.
Optionally, described preliminary identification module adopts another kind of scheme, comprises acquisition module, obtains the sampling point of one section burst signal of current line and lastrow; Computing module is done difference with described current line and lastrow burst signal, and calculates the average absolute of this difference; The first threshold module is set and storage threshold; Comparing unit, with the threshold ratio of the operation result of described computing module and described first threshold module settings, and the output identification signal.Described computing module comprises: the difference arithmetic unit, described current line and lastrow burst signal are done difference; The signed magnitude arithmetic(al) device takes absolute value to described difference; All value arithmetic device is asked described average absolute.The threshold value of described first threshold module settings is T3, and during less than thresholding T3, the output current line is that PAL is capable to described comparing unit at described mean value; Described mean value is during more than or equal to thresholding T3, and the output current line is that NTSC is capable.
Optionally, described preliminary identification module can also adopt the third scheme, comprising: acquisition module, obtain the sampling point of one section burst signal of current line and lastrow; Computing module is asked the phase difference of the burst signal of the burst signal of described current line and lastrow, asks this phase difference average absolute; The first threshold module is set and storage threshold; Comparing unit, with the threshold ratio of the operation result of described computing module and described first threshold module settings, and the output identification signal.Described computing module comprises: phase comparator, ask the phase difference of the burst signal of the burst signal of current line and lastrow; The signed magnitude arithmetic(al) device takes absolute value to described phase difference; All value arithmetic device is asked described average absolute.The threshold value of described first threshold module settings is T4, and during less than thresholding T4, the output current line is that PAL is capable to described comparing unit at described mean value; Described mean value is during more than or equal to thresholding T4, and the output current line is that NTSC is capable.
Optionally, described statistical comparison module comprises: statistical module, add up described local id signal and the continuous opposite number of the marking signal that PAL is capable, NTSC is capable of initial identification signal; Second threshold module is set and storage threshold; Comparing unit, the statistics of more described second threshold module preset threshold and described statistical module, and output comparative result.
Optionally, the described second threshold module preset threshold is M, and the span of M is 16-32.
Optionally, described Logic control module is controlled the directly output or the upset output of signal of described local signal generation circuit according to the comparative result of described statistical comparison module.
Compare with existing technical scheme, the detection method and the device of pal video signal subcarrier phase conversion provided by the invention, by having the capable and capable initial identification signal of NTSC of PAL that the PAL-Switch scheme obtained now and local PAL is capable and NTSC line flag signal compares, statistical comparison result also compares once more with preset threshold, according to the described result who compares once more control local marking signal directly/upset output.Finally output is the local signal that takes place, and output is the result stablize.
Description of drawings
Fig. 1 is the burst signal schematic diagram of the adjacent triplex row of PALD system;
Fig. 2 is first kind of scheme flow chart of existing PAL-Switch scheme;
Fig. 3 is second kind of scheme flow chart of existing PAL-Switch scheme;
Fig. 4 is the third scheme flow chart of existing PAL-Switch scheme;
Fig. 5 is the detection method flow chart of pal video signal subcarrier phase conversion provided by the invention;
Fig. 6 is the detection method flow chart that the present invention adopts first kind of scheme of existing PAL-Switch scheme;
Fig. 7 is the detection method flow chart that the present invention adopts second kind of scheme of existing PAL-Switch scheme;
Fig. 8 is the detection method flow chart that the present invention adopts the third scheme of existing PAL-Switch scheme;
Fig. 9 is the structured flowchart of the checkout gear of pal video signal subcarrier phase conversion provided by the invention;
Figure 10 is the structured flowchart of statistical comparison module provided by the invention;
Figure 11 is the structured flowchart of preliminary identification module of first kind of scheme of corresponding existing PAL-Switch scheme;
Figure 12 is the structured flowchart of preliminary identification module of second kind of scheme of corresponding existing PAL-Switch scheme;
Figure 13 is the structured flowchart of preliminary identification module of first kind of scheme of corresponding existing PAL-Switch scheme;
Figure 14 is the structured flowchart of acquisition module provided by the invention.
Embodiment
For making the purpose, technical solutions and advantages of the present invention clearer, the present invention is described in further detail below in conjunction with accompanying drawing.
The present invention be directed to the improvement project that existing PAL-Switch scheme identification PAL defective capable, the capable existence of NTSC proposes, the PAL that existing PAL-Switch scheme is obtained is capable, the capable identification signal of NTSC is done further processing." obtaining the initial identification signal that PAL is capable, NTSC is capable " of being mentioned herein refers to capable, the capable identification signal of NTSC of PAL that obtains with existing PAL-Switch scheme.Accordingly, the circuit module that PAL is capable, the capable preliminary identification module of NTSC refers to the existing PAL-Switch scheme of realization.
Fig. 2, Fig. 3 and Fig. 4 are identification three kinds of scheme flow charts that PAL is capable and NTSC is capable in the existing PAL-Switch scheme, obtain the initial identification signal that PAL is capable, NTSC is capable.This initial identification signal, just can not be discerned when big (being lower than 50dBu as the RF radiofrequency signal) fully in signal less stable or noise ratio, can cause the thread inverse striped of appearance in the coloured image that final decoding comes out.In order to overcome this defective, the present invention is further processed (as shown in Figure 5) to this initial identification signal, and concrete grammar may further comprise the steps:
A) obtain the initial identification signal that PAL is capable, NTSC is capable;
B) obtain the id signal that local PAL is capable, NTSC is capable;
C) described local id signal and initial identification signal are relatively exported capable, the capable identification signal of NTSC of PAL according to comparative result.
Wherein, step a) is obtained the initial identification signal that PAL is capable, NTSC is capable, adopts and mentions existing PAL-Switch scheme in the background technology.
Fig. 6 is a kind of specific embodiment of the present invention, and first kind of detection scheme that this embodiment adopts in the background technology and mentioned obtains the initial identification signal that PAL is capable, NTSC is capable.As can be seen from Figure 6, this embodiment may further comprise the steps:
1.1, obtain one section (N point) burst signal of lastrow and current line:
With the line synchronizing signal that extracts in the decoding circuit is benchmark, gets N point burst signal sample value at burst signal correspondence position uplifting window, and the span of N is 16-64, is preferably 32;
1.2, the number of statistics current line and the opposite in sign of the corresponding sampling point of burst signal of lastrow:
The burst signal of current line is got XOR with the symbol of the corresponding sampling point of burst signal of lastrow, is 1 result count to XOR;
1.3, with the thresholding of statistics and setting relatively, the type of discerning current line according to the result promptly obtains preliminary recognition result:
Set suitable thresholding T1, T2 (T1＜T2) according to statistical law, statistics with thresholding relatively, if statistics＜T1, then to be identified as PAL capable for current line, recognition result output 1, statistics with thresholding relatively, if statistics＞T2, then to be identified as NTSC capable for current line, recognition result output 0, statistics compares with thresholding, if T1≤described statistics≤T2, then the output of current line recognition result comes to the same thing with the interlacing before the current line;
1.4, obtain that local PAL is capable, NTSC line identifier signal:
Local PAL is capable, NTSC line identifier signal is the signal of upset line by line that local PAL is capable, NTSC line identifier signal generating circuit produces;
1.5, local signal and preliminary recognition result take place relatively, export that final PAL is capable, the capable recognition result of NTSC:
Preliminary recognition result in the step 1.3 is compared with the signal that this locality in the step 1.4 takes place, (domain value range is 16-32 to setting threshold M, preferred value can be 16,20,24,28,32 one of them), opposite as the continuous N row, the signal upset back output that then this locality is taken place, otherwise directly export the local signal that takes place.
Because the local signal that takes place of output as final output signal, can obtain very stable output result like this.
Fig. 7 is an another kind of specific embodiment of the present invention, and second kind of detection scheme that this embodiment adopts in the background technology and mentioned obtains the initial identification signal that PAL is capable, NTSC is capable.As can be seen from Figure 7, this embodiment may further comprise the steps:
2.1, obtain one section (N point) burst signal of lastrow and current line:
With the line synchronizing signal that extracts in the decoding circuit is benchmark, gets N point burst signal sample value at burst signal correspondence position uplifting window, and the span of N is 16-64, is preferably 32;
2.2, the data of current line taken point and the data of previous row are done difference, calculate the average absolute of this difference again;
2.3, with the thresholding of mean value and setting relatively, the type of discerning current line according to the result promptly obtains preliminary recognition result:
Set suitable thresholding T3, with the mean value in the step 2.2 relatively with the thresholding T3 that sets, if mean value less than thresholding T3, then to be identified as PAL capable for current line; If mean value is more than or equal to thresholding T3, then to be identified as NTSC capable for current line;
2.4, obtain that local PAL is capable, NTSC line identifier signal:
Local PAL is capable, NTSC line identifier signal is the signal of upset line by line that local PAL is capable, NTSC line identifier signal generating circuit produces;
2.5, local signal and preliminary recognition result take place relatively, export that final PAL is capable, the capable recognition result of NTSC:
Preliminary recognition result in the step 2.3 is compared with the signal that this locality in the step 2.4 takes place, setting threshold M (domain value range 16-32, preferred value can be 16,20,24,28,32 one of them), opposite as the continuous N row, the signal upset back output that then this locality is taken place, otherwise directly export the local signal that takes place.
Fig. 8 is an another kind of specific embodiment of the present invention, and the third detection scheme that this embodiment adopts in the background technology and mentioned obtains the initial identification signal that PAL is capable, NTSC is capable.As can be seen from Figure 8, this embodiment may further comprise the steps:
3.1, obtain one section (N point) burst signal of lastrow and current line:
With the line synchronizing signal that extracts in the decoding circuit is benchmark, gets N point burst signal sample value at burst signal correspondence position uplifting window, and the span of N is 16-64, is preferably 32;
3.2, ask the phase difference of the burst signal of the burst signal of current line and lastrow, phase difference is taken absolute value, ask this average absolute again;
3.3, with the thresholding of average phase-difference and setting relatively, the type of discerning current line according to the result promptly obtains preliminary recognition result:
Set suitable thresholding T4, with the mean value in the step 3.2 relatively with the thresholding T4 that sets, if mean value less than thresholding T4, then to be identified as PAL capable for current line; If mean value is more than or equal to thresholding T4, then to be identified as NTSC capable for current line;
3.4, obtain that local PAL is capable, NTSC line identifier signal:
Local PAL is capable, NTSC line identifier signal is the signal of upset line by line that local PAL is capable, NTSC line identifier signal generating circuit produces;
3.5, local signal and preliminary recognition result take place relatively, export that final PAL is capable, the capable recognition result of NTSC:
Preliminary recognition result in the step 3.3 is compared with the signal that this locality in the step 3.4 takes place, setting threshold M (domain value range 16-32, preferred value can be 16,20,24,28,32 one of them), opposite as the continuous N row, the signal upset back output that then this locality is taken place, otherwise directly export the local signal that takes place.
Corresponding to the detection method that the pal video signal subcarrier phase of the present invention's proposition is changed, the present invention also provides corresponding checkout gear.Fig. 9 is the structured flowchart of a kind of embodiment of checkout gear of pal video signal subcarrier phase conversion provided by the invention.As can be seen from Figure 9, the checkout gear of present embodiment comprises:
1, obtain the preliminary identification module of the initial identification signal that PAL is capable, NTSC is capable, this module is the testing circuit to the existing PAL-Switch scheme that realizes mentioning in the background technology;
2, local signal generation circuit, this circuit produce the signal of upset line by line, the id signal capable as local PAL, that NTSC is capable;
3, statistical comparison module, more described local id signal and initial identification signal (structured flowchart is as shown in figure 10),
Comprising statistical module, add up described local id signal and the continuous opposite number of the marking signal that PAL is capable, NTSC is capable of initial identification signal,
Second threshold module, set and storage threshold M (domain value range 16-32, preferred value can be 16,20,24,28,32 one of them),
Comparing unit, the statistics of more described threshold value M and described statistical module is also exported comparative result;
4, Logic control module, the output of, NTSC line flag signal capable according to the comparative result of described statistical comparison module control local signal generation circuit PAL; Opposite as the continuous N row, as then this locality to be taken place signal upset back output, otherwise directly export the local signal that takes place.
Corresponding to different existing PAL-Switch schemes, the preliminary identification module that obtains the initial identification signal that PAL is capable, NTSC is capable is different, the preliminary identification module structured flowchart of first kind of scheme, second kind of scheme and the third scheme of the existing PAL-Switch scheme of mentioning in the corresponding respectively background technology of Figure 11, Figure 12 and Figure 13.
As can be seen from Figure 11, the preliminary identification module corresponding to the first kind of scheme that has the PAL-Switch scheme now comprises following components:
Acquisition module obtains the sampling point of one section burst signal of current line and lastrow;
Computing statistical module 1, the number of opposite in sign of adding up the corresponding sampling point of burst signal of described current line and lastrow;
The first threshold module is set and storage threshold T1, T2 T1＜T2;
Comparing unit, with the threshold ratio of the statistics of described computing statistical module and described first threshold module settings, and the output identification signal.During described statistics＜T1, the output current line is that PAL is capable; Described statistics＞T2, the output current line is that NTSC is capable; T1≤described statistics≤T2, the output current line is identical with before interlaced type.
Wherein computing statistical module 1 comprises: the XOR unit, current line is got XOR with the corresponding sampling point of the burst signal of lastrow; Counter is 1 counting to the XOR result.
As can be seen from Figure 12, the preliminary identification module corresponding to the second kind of scheme that has the PAL-Switch scheme now comprises following components:
Acquisition module obtains the sampling point of one section burst signal of current line and lastrow;
The first threshold module is set and storage threshold T3;
Comparing unit, with the threshold ratio of the operation result of described computing module and described first threshold module settings, and the output identification signal.Described mean value is during less than thresholding T3, and the output current line is that PAL is capable; Described mean value is during more than or equal to thresholding T3, and the output current line is that NTSC is capable.
Wherein, computing module 2 comprises: the difference arithmetic unit, described current line and lastrow burst signal are done difference; The signed magnitude arithmetic(al) device takes absolute value to described difference; All value arithmetic device is asked described average absolute.
As can be seen from Figure 13, the preliminary identification module corresponding to the third scheme that has the PAL-Switch scheme now comprises following components:
Acquisition module obtains the sampling point of one section burst signal of current line and lastrow;
The first threshold module is set and storage threshold T4;
Comparing unit, with the threshold ratio of the operation result of described computing module and described first threshold module settings, and the output identification signal.Described mean value is during less than thresholding T4, and the output current line is that PAL is capable; Described mean value is during more than or equal to thresholding T4, and the output current line is that NTSC is capable.
Wherein computing module 3 comprises: phase comparator, ask the phase difference of the burst signal of the burst signal of current line and lastrow; The signed magnitude arithmetic(al) device takes absolute value to described phase difference; All value arithmetic device is asked described average absolute.
The structured flowchart of the acquisition module in the preliminary identification module of the existing PAL-Switch scheme of employing as shown in figure 14.
Under situation without departing from the spirit and scope of the present invention, can also constitute many very embodiment of big difference that have.Should be appreciated that except as defined by the appended claims, the invention is not restricted at the specific embodiment described in the specification.
Claims (28)
1. the detection method of pal video signal subcarrier phase conversion may further comprise the steps:
A) obtain the initial identification signal that PAL is capable, NTSC is capable;
B) obtain the id signal that local PAL is capable, NTSC is capable;
C) described local id signal and initial identification signal are relatively exported capable, the capable identification signal of NTSC of PAL according to comparative result.
2. the detection method of pal video signal subcarrier phase conversion according to claim 1 is characterized in that step a) comprises:
a
11) obtain the sampling point of one section burst signal of current line and lastrow;
a
12) number of opposite in sign of the corresponding sampling point of burst signal of statistics described current line and lastrow;
a
13) thresholding of described statistics and setting is compared, discern the type of current line according to the result.
3. the detection method of pal video signal subcarrier phase conversion according to claim 2 is characterized in that step a
11) comprising:
With the line synchronizing signal is benchmark, gets the burst signal sample value at burst signal correspondence position uplifting window.
4. the detection method of pal video signal subcarrier phase conversion according to claim 2 is characterized in that step a
12) comprising:
The corresponding sampling point of the burst signal of described current line and lastrow is got XOR;
It to XOR 1 result count.
5. the detection method of pal video signal subcarrier phase conversion according to claim 2 is characterized in that step a
13) comprising:
Setting thresholding T1, T2 (T1＜T2);
With described step a
12) in statistics and thresholding relatively, if described statistics＜T1, then current line is that PAL is capable; If described statistics＞T2, then current line is that NTSC is capable; If T1≤described statistics≤T2, then current line is identical with before interlaced type.
6. the detection method of pal video signal subcarrier phase conversion according to claim 1 is characterized in that step a) comprises:
a
21) obtain one section burst signal of current line and lastrow;
a
22) described current line and lastrow burst signal are done difference, and calculate the average absolute of this difference;
a
23) thresholding of described mean value and setting is compared, discern the type of current line according to the result.
7. the detection method of pal video signal subcarrier phase conversion according to claim 6 is characterized in that step a
21) comprising:
With the line synchronizing signal is benchmark, gets the burst signal sample value at burst signal correspondence position uplifting window.
8. the detection method of pal video signal subcarrier phase conversion according to claim 6 is characterized in that step a
23) comprising:
Set thresholding T3, with step a
22) in mean value with the thresholding T3 that sets relatively, if mean value less than thresholding T3, then to be identified as PAL capable for current line; If mean value is more than or equal to thresholding T3, then to be identified as NTSC capable for current line.
9. the detection method of pal video signal subcarrier phase conversion according to claim 1 is characterized in that step a) comprises:
a
31) obtain one section burst signal of current line and lastrow;
a
32) ask the phase difference of the burst signal of the burst signal of described current line and lastrow, ask this phase difference average absolute;
a
33) thresholding of described mean value and setting is compared, discern the type of current line according to the result.
10. the detection method of pal video signal subcarrier phase conversion according to claim 9 is characterized in that step a
31) comprising:
With the line synchronizing signal is benchmark, gets the burst signal sample value at burst signal correspondence position uplifting window.
11. the detection method of pal video signal subcarrier phase conversion according to claim 9 is characterized in that step a
33) comprising:
Set thresholding T4, with step a
32) in mean value with the thresholding T4 that sets relatively, if mean value less than thresholding T4, then to be identified as PAL capable for current line; If mean value is more than or equal to thresholding T4, then to be identified as NTSC capable for current line.
12. the detection method according to claim 1 or 2 or 6 or 9 described pal video signal subcarrier phase conversions is characterized in that, local id signal and initial identification signal are a signal that overturns line by line.
13. the detection method according to claim 1 or 2 or 6 or 9 described pal video signal subcarrier phase conversions is characterized in that step C) comprising:
Set a threshold value M, described local id signal is above opposite with initial identification signal continuous N row, with local id signal upset output, otherwise directly exports local id signal.
14. the detection method of pal video signal subcarrier phase conversion according to claim 13 is characterized in that described threshold value M span is 16-32.
15. the checkout gear of a pal video signal subcarrier phase conversion comprises the preliminary identification module that obtains the initial identification signal that PAL is capable, NTSC is capable, it is characterized in that described checkout gear also comprises:
Local signal generation circuit produces the id signal that local PAL is capable, NTSC is capable;
The statistical comparison module, more described local id signal and described initial identification signal;
Logic control module, the output of, NTSC line flag signal capable according to the comparative result of described statistical comparison module control local signal generation circuit PAL.
16. the checkout gear of pal video signal subcarrier phase conversion according to claim 15 is characterized in that described preliminary identification module comprises:
Acquisition module obtains the sampling point of one section burst signal of current line and lastrow;
The computing statistical module, the number of opposite in sign of adding up the corresponding sampling point of burst signal of described current line and lastrow;
The first threshold module is set and storage threshold;
Comparing unit, with the threshold ratio of the statistics of described computing statistical module and described first threshold module settings, and the output identification signal.
17. the checkout gear of pal video signal subcarrier phase conversion according to claim 16 is characterized in that described computing statistical module comprises:
The XOR unit is got XOR with current line with the corresponding sampling point of the burst signal of lastrow;
Counter is 1 counting to the XOR result.
18. the checkout gear of pal video signal subcarrier phase conversion according to claim 16 is characterized in that the threshold value of described first threshold module settings is T1, T2, T1＜T2.
19. the checkout gear of pal video signal subcarrier phase according to claim 16 conversion is characterized in that, described comparing unit is when described statistics＜T1, and the output current line is that PAL is capable;
Described statistics＞T2, the output current line is that NTSC is capable; T1≤described statistics≤T2, the output current line is identical with before interlaced type.
20. the checkout gear of pal video signal subcarrier phase conversion according to claim 15 is characterized in that described preliminary identification module comprises:
Acquisition module obtains the sampling point of one section burst signal of current line and lastrow;
Computing module is done difference with described current line and lastrow burst signal, and calculates the average absolute of this difference;
The first threshold module is set and storage threshold;
Comparing unit, with the threshold ratio of the operation result of described computing module and described first threshold module settings, and the output identification signal.
21. the checkout gear of pal video signal subcarrier phase conversion according to claim 20 is characterized in that described computing module comprises:
The difference arithmetic unit is done difference with described current line and lastrow burst signal;
The signed magnitude arithmetic(al) device takes absolute value to described difference;
All value arithmetic device is asked described average absolute.
22. the checkout gear of pal video signal subcarrier phase according to claim 20 conversion is characterized in that the threshold value of described first threshold module settings is T3, during less than thresholding T3, the output current line is that PAL is capable to described comparing unit at described mean value; Described mean value is during more than or equal to thresholding T3, and the output current line is that NTSC is capable.
23. the checkout gear of pal video signal subcarrier phase conversion according to claim 15 is characterized in that described preliminary identification module comprises:
Acquisition module obtains the sampling point of one section burst signal of current line and lastrow;
Computing module is asked the phase difference of the burst signal of the burst signal of described current line and lastrow, asks this phase difference average absolute;
The first threshold module is set and storage threshold;
Comparing unit, with the threshold ratio of the operation result of described computing module and described first threshold module settings, and the output identification signal.
24. the checkout gear of pal video signal subcarrier phase conversion according to claim 23 is characterized in that described computing module comprises:
Phase comparator is asked the phase difference of the burst signal of the burst signal of current line and lastrow; The signed magnitude arithmetic(al) device takes absolute value to described phase difference;
All value arithmetic device is asked described average absolute.
25. the checkout gear of pal video signal subcarrier phase according to claim 23 conversion is characterized in that the threshold value of described first threshold module settings is T4, during less than thresholding T4, the output current line is that PAL is capable to described comparing unit at described mean value; Described mean value is during more than or equal to thresholding T4, and the output current line is that NTSC is capable.
26. the checkout gear according to claim 15 or 16 or 20 or 23 described pal video signal subcarrier phase conversions is characterized in that described statistical comparison module comprises:
Statistical module is added up described local id signal and the continuous opposite number of the marking signal that PAL is capable, NTSC is capable of initial identification signal;
Second threshold module is set and storage threshold;
Comparing unit, the statistics of more described second threshold module preset threshold and described statistical module, and output comparative result.
27. the checkout gear of pal video signal subcarrier phase conversion according to claim 26 is characterized in that the described second threshold module preset threshold is M, the span of M is 16-32.
28. checkout gear according to claim 15 or 16 or 20 or 23 described pal video signal subcarrier phase conversions, it is characterized in that described Logic control module is controlled the directly output or the upset output of signal of described local signal generation circuit according to the comparative result of described statistical comparison module.
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| CN100584038C (en) * | 2008-04-01 | 2010-01-20 | 西安交通大学 | Video signal decoder based on 3D self-adapting comb filtering |
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| CN117596371A (en) * | 2024-01-18 | 2024-02-23 | 浙江芯劢微电子股份有限公司 | Method and device for judging phase alternating identification |
| CN117596371B (en) * | 2024-01-18 | 2024-04-30 | 浙江芯劢微电子股份有限公司 | Method and device for judging phase alternating identification |
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