CN107592518B - A kind of composite video signal quality index determines method and device - Google Patents
A kind of composite video signal quality index determines method and device Download PDFInfo
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Abstract
The invention discloses a kind of composite video signal quality index to determine method and device, which comprises the coenvelope line for obtaining composite video signal determines the first range value of the coenvelope line wave crest；According to first range value, the value range of luminance component amplitude in the composite video signal is determined, and determine the value range of coloration relative luminance delay in the composite video signal；To the luminance component amplitude and coloration relative luminance delay difference assignment in corresponding value range, the assignment is substituted into and be delayed with the luminance component amplitude, the coloration relative luminance as in the coenvelope line function of variable, and determines the second range value of the wave crest of the function of the coenvelope line of substitution assignment；When second range value and the first range value difference are less than preset value, the bright gain inequality of color and the bright delay inequality of color of the composite video signal are determined by each assignment that the luminance component amplitude and the coloration relative luminance are delayed.
Description
Technical field
The present invention relates to video measurement technologies, and in particular to a kind of composite video signal quality index determines method and dress
It sets.
Background technique
Composite video signal (CVBS, Composite Video Broadcast Signal) is the mark being widely used
Standard, also referred to as base band video or RCA (Radio Corporation of American) video is transmitted with analog waveform
Data.Composite video includes color difference (tone and saturation degree) and brightness (light) information, and they are synchronized in blanking pulse,
It is transmitted with same signal.It specifically further include PAL system (PAL, Phase Alteration Line) and state, the U.S. in actual use
Family's television standard committee system (NTSC, National Television Standards Committee) two kinds of standards, they
Identical interface is used with CVBS, is more specific conjunction vision signal standard.
Many television sets are designed with CVBS interface at present, i.e. yellow is vision signal, white for left channel audio letter
Number, it is red for right channel audio signal.The set-top box and network machine top box of most of cable televisions are also provided with CVBS interface,
Analog signal, i.e. CVBS signal can be converted digital signals into this way, and pass through television for play.
The method for converting digital signals into CVBS signal is very more, converts generally by CVBS decoding chip, still
CVBS signal is more complex composite video signal, containing indexs such as multiple analog voltage level, time intervals, and all views
Frequency information only uses transmission lines transmission, different by the combination of luminance information, color information and synchronization signal in a signal
The video signal quality that converts of CVBS decoding chip it is widely different, it is therefore desirable to put goods on the market in CVBS decoding chip
It is preceding to make stringent test, to verify the quality of CVBS decoding chip.
The method of test can be the vision signal that test CVBS decoding chip converts, and can also decode core in CVBS
Before piece is also manufactured without out, pass through the register transfer level (RTL, Register Transfer Level) of CVBS decoding chip
Code simulates CVBS signal by simulator, tests the CVBS signal after simulation.
Above-mentioned test method can all influence the bright gain inequality of color of video quality and the determination of the bright delay poor index of color, and error is non-
Chang great, this directly affects the Quality estimation to CVBS signal.
It is that CVBS signal is sent into decoder there are also test method, enters luminance channel all the way, by color negative carrier trap
Device (4.43mhz trapper) sponges carrier chrominance signal, and takes out luminance signal, and another way is taken out by bandpass filter
The carrier chrominance signal of 4.43mhz measures the amplitude of the two signals respectively and observes envelope in the delay of time domain.This test side
Method causes error very big due to that when signal is taken out in distribution, can introduce additional amplitude distortion and timing distortion.
Summary of the invention
To solve existing technical problem, an embodiment of the present invention is intended to provide a kind of composite video signal quality index
Determine method and device, the bright gain inequality of color of the CVBS signal after capable of more accurately determining the conversion of CVBS decoding chip and color is bright prolongs
The time difference judges the conversion quality of CVBS decoding chip.
The technical solution of the embodiment of the present invention is achieved in that
The embodiment of the invention provides a kind of composite video signal quality index to determine method, which comprises
The coenvelope line for obtaining composite video signal, determines the first range value of the coenvelope line wave crest；
According to first range value, the value range of luminance component amplitude in the composite video signal is determined, and really
The value range of coloration relative luminance delay in the fixed composite video signal；
It, will be described to the luminance component amplitude and coloration relative luminance delay difference assignment in corresponding value range
Assignment, which is substituted into, to be determined with the luminance component amplitude, coloration relative luminance delay in the coenvelope line function of variable
Substitute into the second range value of the wave crest of the function of the coenvelope line of assignment；
When second range value and the first range value difference are less than preset value, pass through the luminance component amplitude
The bright gain inequality of color and the bright delay inequality of color of the composite video signal are determined with each assignment of coloration relative luminance delay.
Preferably, the coenvelope line for obtaining composite video signal, comprising:
The peak point in the composite video signal each period is obtained, the peak point is connected, forms coenvelope line.
Preferably, the first range value of the determination coenvelope line wave crest, comprising:
The peak point for obtaining the coenvelope line measures the amplitude of the peak point, obtains first range value.
Preferably, in the determination composite video signal luminance component amplitude value range, comprising:
According to first range value, determine that the value range of luminance component amplitude in the composite video signal is zero to arrive
First range value；
The value range that coloration relative luminance is delayed in the determination composite video signal, comprising:
In the composite video signal coloration relative luminance be delayed range be more than or equal to-π, and be less than or equal to π.
Preferably, the second range value of the wave crest of the function of the determining coenvelope line for substituting into assignment, including；
Based on the function of the coenvelope line for substituting into assignment, the function of the coenvelope line for substituting into assignment is calculated most
Big value, is determined as second range value for maximum value calculated.
Preferably, the method also includes；
Based on the respective coenvelope line of the multiple composite video signal that multiple composite video signals obtain respectively, it is based on
Each coenvelope line determines the bright gain inequality of the respective color of the multiple composite video signal and the bright delay inequality of color respectively；
The bright gain inequality of multiple colors and the bright delay inequality of color are averaged respectively respectively；
Using the average value as the bright gain inequality of the color of the composite video signal and the bright delay inequality of color.
The embodiment of the invention also provides a kind of composite video signal quality index determining device, described device includes obtaining
Module, the first determining module, the second determining module, third determining module and the 4th determining module；Wherein,
The acquisition module, for obtaining the coenvelope line of composite video signal；
First determining module, for determining the first range value of the coenvelope line wave crest；
Second determining module, for according to first range value, determining brightness point in the composite video signal
The value range of discharge amplitude, and determine the value range of coloration relative luminance delay in the composite video signal；
The third determining module, for relatively bright to the luminance component amplitude and coloration in corresponding value range
Degree delay difference assignment, the assignment is substituted into and is delayed with the luminance component amplitude, the coloration relative luminance as variable
In coenvelope line function, and determine the second range value for substituting into the wave crest of the function of coenvelope line of assignment；
4th determining module, for being less than preset value when second range value and the first range value difference
When, the color of the composite video signal is determined by each assignment that the luminance component amplitude and the coloration relative luminance are delayed
Bright gain inequality and the bright delay inequality of color.
Preferably, the acquisition module is also used to:
The peak point in the composite video signal each period is obtained, the peak point is connected, forms coenvelope line.
Preferably, first determining module is also used to:
The peak point for obtaining the coenvelope line measures the amplitude of the peak point, obtains first range value.
Preferably, second determining module is also used to:
According to first range value, determine that the value range of luminance component amplitude in the composite video signal is zero to arrive
First range value；
Second determining module is also used to determine the value model that coloration relative luminance is delayed in the composite video signal
Enclose: in the composite video signal coloration relative luminance be delayed range be more than or equal to-π, and be less than or equal to π.
Preferably, the third determining module is also used to:
Based on the function of the coenvelope line for substituting into assignment, the function of the coenvelope line for substituting into assignment is calculated most
Big value, is determined as second range value for maximum value calculated.
Preferably, the 4th determining module is also used to:
Based on the respective coenvelope line of the multiple composite video signal that multiple composite video signals obtain respectively, it is based on
Each coenvelope line determines the bright gain inequality of the respective color of the multiple composite video signal and the bright delay inequality of color respectively；
The bright gain inequality of multiple colors and the bright delay inequality of color are averaged respectively respectively；
Using the average value as the bright gain inequality of the color of the composite video signal and the bright delay inequality of color.
The embodiment of the present invention provides a kind of composite video signal quality index and determines method and device, obtains composite video letter
Number coenvelope line, determine the first range value of the coenvelope line wave crest；According to first range value, determine described compound
The value range of luminance component amplitude in vision signal, and determine taking for coloration relative luminance delay in the composite video signal
It is worth range；It, will be described to the luminance component amplitude and coloration relative luminance delay difference assignment in corresponding value range
Assignment, which is substituted into, to be determined with the luminance component amplitude, coloration relative luminance delay in the coenvelope line function of variable
Substitute into the second range value of the wave crest of the function of the coenvelope line of assignment；When second range value and the first amplitude value difference
When value is less than preset value, determined by each assignment that the luminance component amplitude and the coloration relative luminance are delayed described compound
The bright gain inequality of the color of vision signal and the bright delay inequality of color；As it can be seen that the embodiment of the present invention passes through the approximate calculation to CVBS signal, energy
The quality index for more accurately determining the bright gain inequality of color and the bright delay inequality of color, judges the conversion quality of CVBS decoding chip.
Detailed description of the invention
Fig. 1 is the flow diagram that one composite video signal quality index of the embodiment of the present invention determines method；
Fig. 2 is the 20T impulse waveform schematic diagram of one composite video signal of the embodiment of the present invention；
Fig. 3 is that the frequency of one composite video signal of the embodiment of the present invention tends to just infinite schematic diagram one；
Fig. 4 is that the frequency of one composite video signal of the embodiment of the present invention tends to just infinite schematic diagram two；
Fig. 5 is that the frequency of one composite video signal of the embodiment of the present invention tends to just infinite schematic diagram three；
Fig. 6 is that the frequency of one composite video signal of the embodiment of the present invention tends to just infinite schematic diagram four；
Fig. 7 is the waveform diagram that the envelope of Fig. 3 is individually taken out to formation；
Fig. 8 is the flow diagram that two composite video signal quality index of the embodiment of the present invention determines method；
Fig. 9 is the schematic diagram of triplex of embodiment of the present invention video signal quality index determining device.
Specific embodiment
The basic principle of the embodiment of the present invention are as follows: calculate the chrominance component amplitude that the bright gain inequality of color and the bright delay inequality of color need
AC, luminance component amplitude AYIt is delayed with coloration relative luminanceIt can not directly measure, but can first survey from composite video signal
Measure the envelope wave crest of composite video signal, the actual measurement range value of trough；It establishes with the chrominance component amplitude, luminance component
Amplitude and the delay of coloration relative luminance are the envelope line function of variable, then according to this function, in AYWithTheoretical value model
In enclosing, to AYWithMultiple assignment tentative calculation, obtain envelope wave crest, trough theoretical amplitude value, Step wise approximation survey amplitude
Value, finally obtains the A of setting accuracyC、AYWithThe principle of the embodiment of the present invention is obtained by a kind of approximate calculation method
The quality index of composite video signal, this approximate calculation method are well suited for calculating by computer.
The present invention is described further again below in conjunction with the accompanying drawings and the specific embodiments.
Embodiment one
Fig. 1 is the flow diagram that one composite video signal quality index of the embodiment of the present invention determines method, the method
Executing subject can be test host, more specifically can be a computer, as shown in Figure 1, which comprises
Step 101: obtaining the coenvelope line of composite video signal, determine the first range value of the coenvelope line wave crest；
Here, the coenvelope line of composite video signal is obtained by test host, the composite video signal is to be tested
Standard signal pass through simulation dress usually according to composite video decoding chip, that is, the RTL code of CVBS decoding chip
The composite video signal simulated is set, is digital signal, can directly be tested host acquisition；It is also possible to from composite video solution
Code chip directly exports, that is, can be needed to pass through analog-digital commutator by the received CVBS signal of general analog television machine
Host acquisition could be tested；
The acquisition of the coenvelope line is obtained and connecting the peak point of the composite video signal, specifically
Ground is handled by application program, and the application program is equipped with specific algorithm, can automatically capture the composite video
The peak point of signal, then the tangent line tangent with the peak point is drawn, finally tangent line is smoothly connected, the application program
Generally it is mounted in the video frequency signal processing application program of test host.
Specifically, the video processing applications program of the test host can be matrix labotstory (MATLAB, Matrix
Laboratory)。
Testing the concrete signal of the bright gain inequality of color and the bright delay inequality of color in composite video signal is 20T impulse waveform, 20T arteries and veins
The definition of punching, in the waveform of 20T pulse, when amplitude reaches the half of maximum value, between two corresponding time points away from
From being the time cycle for 20T, T；Specific to standard, for PAL, T 100ns；For NTSC, T 125ns.
In 20T pulse, coloration and luminance signal are Sine-squared waves, and carrier chrominance signal is superimposed upon in luminance signal.
Fig. 2 is the 20T impulse waveform in the present embodiment, and the π of ω=2 f, f are the carrier frequency of composite video signal.
In order to preferably observe 20T impulse waveform, it is assumed that the frequency of the composite video signal tends to just infinite, in this way,
The envelope of composite video signal becomes apparent from, and is specifically shown in Fig. 3~Fig. 6, and Fig. 3~Fig. 6 is that chromatic component and luminance component are Bu Tong special
Four seed types of sign, in which:
ACAnd AYThe respectively amplitude of chromatic component and luminance component,For the delay of coloration relative luminance.
Fig. 3 is characterized in: AC>AY,That is the amplitude of the chromatic component amplitude that is greater than luminance component, coloration is bright in advance
Degree；
Fig. 4 is characterized in: AC>AY,That is amplitude of the amplitude of chromatic component greater than luminance component, coloration lag
Brightness；
Fig. 5 is characterized in: AC<AY,That is the amplitude of the chromatic component amplitude that is less than luminance component, coloration is advanced
Brightness；
Fig. 6 is characterized in: AC<AY,That is amplitude of the amplitude of chromatic component less than luminance component, coloration lag
Brightness；
What above-mentioned figure was characterized in being obtained according to the shape qualitative analysis of envelope.
Further, envelope in Fig. 3 is individually shown, obtains envelope shown in Fig. 7.
First range value of the coenvelope line wave crest is the value of M shown in Fig. 7, determine first range value be for
The value range of luminance component amplitude and the delay of coloration relative luminance in composite video signal is determined in the next steps；
The method for determining first range value may include: the peak point for obtaining the coenvelope line, measure the peak
It is worth the amplitude of point, obtains first range value, i.e., the value of M shown in Fig. 7.
Step 102: according to first range value, determining the value model of luminance component amplitude in the composite video signal
It encloses, and determines the value range of coloration relative luminance delay in the composite video signal；
Need to establish luminance component amplitude in the composite video signal, coloration point after obtaining first range value
Discharge amplitude, coloration relative luminance are delayed and the relational expression of M, then determines therefrom that luminance component amplitude, coloration relative luminance
The value range of delay, specific as follows:
According to the principle of composite video signal, it is known that the coloration and brightness waveform of composite video signal are respectively Sine-squared
Wave, therefore available AC、AYWithIt is expressed as the canonical function of the envelope of composite video signal as variable, specifically, in Fig. 7
Coenvelope line and lower envelope line use respectively following formula (1), (2) indicate.
In above-mentioned two formula, CVBS_t is coenvelope line, and CVBS_b is lower envelope line, ACAnd AYRespectively chromatic component and bright
The amplitude of component is spent,For the delay of coloration relative luminance.
According to formula (1), it is assumed that the delay of coloration relative luminance is zero, i.e.,It can then obtain: M=AY+Ac；
And Ac is Sine-squared, is greater than or equal to zero, so AYIt is not more than M, therefore A can be obtainedYValue range be
0 arrives M, i.e., the value range of luminance component amplitude is zero to first range value in the described composite video signal；
By the characteristics of SIN function it is found that in formula (1)Period is 2 π, andFor coloration relative luminance
Delay, it is possible to advanced, it is also possible to lag, therefore settableValue range be and to be less than or equal to more than or equal to-π
π,Value range can be expressed as [- π, π].
Step 103: the luminance component amplitude and the delay of coloration relative luminance being assigned respectively in corresponding value range
The assignment is substituted into and is delayed with the luminance component amplitude, the coloration relative luminance as the coenvelope line function of variable by value
In, and determine the second range value for substituting into the wave crest of the function of coenvelope line of assignment；
When second range value and the first range value difference are less than preset value, pass through the luminance component amplitude
The bright gain inequality of color and the bright delay inequality of color of the composite video signal are determined with each assignment of coloration relative luminance delay.
Specifically, distinguish to be delayed in corresponding value range to the luminance component amplitude and coloration relative luminance
After assignment, can determine that the second range value of the wave crest of the function of the coenvelope line, need to the envelope canonical function into
Row transformation obtains the relationship of luminance component amplitude and coloration relative luminance delay and the second range value of the envelope wave crest
Formula；
Certainly, during assignment tentative calculation, it is also necessary to some other formula, it is clear in order to describe, first by calculating process
In all formula for using first derive one by one:
Notice that formula (1) is there are a maximum, and there are a maximum and minimums for formula (2) as ω t ∈ [0, π].
Therefore respectively to formula (1) and formula (2) to t derivation, formula (3) and formula (4) are obtained.
When formula (1) and formula (2) reach maximum value or minimum value, formula (3) and formula (4) are respectively equal to 0, obtain (5) and formula
(6)。
If the t for meeting formula (5) is tt, the t for meeting formula (6) is tb1And tb2；According to tb1And tb2Relationship can obtain formula (7):
In conjunction with Fig. 7, by tt、tb1、tb2Formula (1) and formula (2) are substituted into formula (7), obtains formula (8), (9), (10):
Formula (9) is added to obtain formula (11) with formula (10):
AY-AC=Y1+Y2 (11)
Then formula (12) are derived by by formula (5):
Finally obtain formula (13):
Similarly, formula (14) can be derived by by formula (6):
After deriving above-mentioned formula, to AYWithAssignment is distinguished in value range, is found out accordingly according to assignment with formula (11)
AC；Acquire ACAfterwards, by AC、AYWithSubstitution formula (13) finds out ω tt；
The ω t that will be acquiredtSubstitution formula (8), determines the second range value of the coenvelope line, that is, calculates the substitution
The maximum value of the function of the coenvelope line of assignment, is denoted as M ',
To AYWithContinue assignment in the value range of setting, obtains the second range value of multiple coenvelope lines；
When second range value and the first range value difference are less than preset value, pass through the luminance component amplitude
The bright gain inequality of color and the bright delay inequality of color of the composite video signal are determined with each assignment of coloration relative luminance delay；
Specifically, it is calculated by following formula:
The result that formula (15) acquires is the bright gain inequality of color, unit %；
The result that formula (16) acquires is the bright delay inequality of color, unit ns；If calculated result is negative, illustrate that coloration lags,
If calculated result is positive, illustrate that coloration is advanced；
Wherein, N is constant, because being 20T pulse, taking 20, T is the time cycle；Specific to standard, for PAL, T
For 100ns；For NTSC, T 125ns；
Default difference value is according to composite video decoding chip, i.e., the requirement of CVBS decoding chip determines, is not repeated.
Further, in order to keep calculated result more acurrate, multiple waveforms can be extracted from composite video signal, are counted respectively
Calculate the bright gain inequality of color and the bright delay inequality of color；
Specifically, the respective coenvelope of the multiple composite video signal obtained respectively based on multiple composite video signals
Line determines the bright gain inequality of the respective color of the multiple composite video signal and the bright delay inequality of color based on each coenvelope line respectively；
The bright gain inequality of multiple colors and the bright delay inequality of color are averaged respectively respectively；
Using the average value as the bright gain inequality of the color of the composite video signal and the bright delay inequality of color
More specifically, according to composite video signal principle, it is known that the waveform of 20T pulse be initial phase be zero degree, 90 degree,
180 degree, the four of 270 degree kinds of waveform cycles, wherein zero degree, 180 degree and 90 degree, 270 degree of shape are just the same, only wave crest wave
Paddy is contrary, as long as therefore calculate the index of zero degree and 90 degree of both waveforms, and be averaged, it may be assumed that
The composite video signal for being zero according to initial phase calculates the bright gain inequality of the first color and the bright delay inequality of the first color:
The composite video signal for being 90 degree according to initial phase, calculates the bright gain inequality of the second color and the bright delay inequality of the second color；
The bright gain inequality of color is obtained according to the average value of the bright gain inequality of the first color and the bright gain inequality of the second color, it is bright according to the first color
The average value of delay inequality and the bright delay inequality of the second color obtains the bright delay inequality of color.
Embodiment two
Fig. 8 is the flow diagram that two composite video signal quality index of the embodiment of the present invention determines method, the method
Executing subject can be test host, more specifically can be a computer, as shown in Figure 8, which comprises
Step 201: determining the actual measurement range value of the coenvelope line of composite video signal, the wave crest of lower envelope line, trough；
Due to embodiment one determine luminance component amplitude and coloration relative luminance delay value range be it is bigger,
The workload of calculating is bigger, this step on the basis of example 1, tries to reduce luminance component amplitude and coloration is relatively bright
Spend the value range of delay；
Specifically, coenvelope line on the basis of one step 101 of embodiment, in addition to obtaining the composite video signal
Outside, the lower envelope line of the composite video signal is also obtained, it is determined that the reality of coenvelope line, the wave crest of lower envelope line, trough
Range value is surveyed, respectively corresponds M, Y1 and Y2 in Fig. 7；
In this way, in subsequent steps, luminance component amplitude and the delay of coloration relative luminance can be more accurately determined
Value range.
Step 202: determining the value model of luminance component amplitude and the delay of coloration relative luminance in the composite video signal
It encloses；
On the basis of one step 102 of embodiment, this step further determines that luminance component amplitude and coloration relative luminance
The value range of delay, specific as follows:
1) value range of luminance component amplitude is determined:
Previously described formula (11) are substituted into formula (8), A can be obtainedYValue range are as follows:
2) value range of coloration relative luminance delay is determined:
The value range for determining the delay of coloration relative luminance in embodiment one in step 102 is [- π, π]；
ButFor square of SIN function, according to the characteristics of SIN function it is found that square after period contract
It is half, so the value range that coloration relative luminance can be delayed is set as [- pi/2, pi/2]；
Further, formula (13) is and to determine that second range value has direct relationship for calculating ω t, before
Some formula be intended merely to derive formula (13), in formula (13)Value range just determine coloration relative luminance delay
Value range, therefore further qualitative analysis is made to formula (13), from (13) as can be seen that tg (2 ω t) is tangent function, just
Cutting period of a function is π, and in tg (2 ω t) is 2 times of ω t, and the period reduces half, and the period is pi/2, so coloration is relatively bright
The value range of degree delay is also possible to pi/2, thus the value range of coloration relative luminance delay can be set to [- π/4, π/
4]。
Step 203: the luminance component amplitude and the delay of coloration relative luminance being assigned respectively in corresponding value range
The assignment is substituted into coenvelope line, the lower packet being delayed with the luminance component amplitude, the coloration relative luminance as variable by value
In winding thread function, and determine the theoretical amplitude value of the wave crest of the function of the coenvelope line, lower envelope line that substitute into assignment, trough；
When the difference of the theoretical amplitude value and the actual measurement range value is less than preset value, pass through the luminance component width
Degree and each assignment of coloration relative luminance delay determine the bright gain inequality of the color of the composite video signal and the bright delay inequality of color.
On the basis of one step 103 of embodiment, this step also needs to calculate wave crest, the trough of the lower envelope line function
Theoretical amplitude value；
Specifically, to AYWithAssignment is distinguished in value range, and corresponding A is found out with formula (11) according to assignmentC；Acquire AC
Afterwards, by AC、AYWithSubstitution formula (13), formula (14) and formula (7) find out ω tt、ωtb1With ω tb2If paying attention to ω tb1Less than 0, then
By ω tb1In addition pi/2 is as the ω t calculated belowb1, i.e.,
The ω t that will be acquiredt、ωtb1With ω tb2Substitution formula (8) (9) (10), determines the wave of coenvelope line, lower envelope line function
The theoretical amplitude value at peak, trough, i.e. the value of M ', Y1 ' and Y2 ', respectively with the reality of coenvelope line, the wave crest of lower envelope line, trough
It surveys range value M, Y1 and Y2 to subtract each other, the absolute value of three differences is added, the sum of three differences are set as S.
To AYWithContinue assignment in the value range of setting, obtains the wave of multiple coenvelope lines, lower envelope line function
The theoretical amplitude value at peak, trough；
Calculate the theoretical amplitude value of multiple coenvelope lines, the wave crest of lower envelope line function, trough, respectively with coenvelope
The actual measurement range value calculating of line, the wave crest of lower envelope line, trough, obtains multiple S, when S is less than default difference value, by described
Each assignment of luminance component amplitude, chrominance component amplitude and coloration relative luminance delay determines the composite video signal
The bright gain inequality of color and the bright delay inequality of color, calculation formula are shown in formula (15), (16).
Embodiment three
Fig. 9 is the schematic diagram of triplex of embodiment of the present invention video signal quality index determining device, as shown in figure 9, institute
Stating device includes: to obtain module 31, the first determining module 32, the second determining module 33, third determining module 34 and the 4th to determine
Module 35；Wherein,
The acquisition module 31, for obtaining the coenvelope line of composite video signal；
First determining module 32, for determining the first range value of the coenvelope line wave crest；
Second determining module 33, for determining brightness in the composite video signal according to first range value
The value range of component amplitude, and determine the value range of coloration relative luminance delay in the composite video signal；
The third determining module 34, for opposite to the luminance component amplitude and coloration in corresponding value range
Brightness delay difference assignment, the assignment is substituted into and is delayed with the luminance component amplitude, the coloration relative luminance as variable
Coenvelope line function in, and determine substitute into assignment coenvelope line function wave crest the second range value；
4th determining module 35, for being less than preset value when second range value and the first range value difference
When, the color of the composite video signal is determined by each assignment that the luminance component amplitude and the coloration relative luminance are delayed
Bright gain inequality and the bright delay inequality of color.
In order to illustrate become apparent from, will elaborate respectively to modules below:
The acquisition module 31, for obtaining the coenvelope line of composite video signal；
The composite video signal is standard signal to be tested, usually according to the RTL generation of composite video decoding chip
Code, the composite video signal simulated by simulator is digital signal, can directly be acquired the acquisition of module 31；It can also
To be directly to be exported from composite video decoding chip, that is, can be needed by the received CVBS signal of general analog television machine
The acquisition of module 31 can be just acquired by analog-digital commutator；
The acquisition of the coenvelope line is obtained and connecting the peak point of the waveform of the composite video signal
, specifically handled by application program, the application program is equipped with specific algorithm, can automatically capture described
The peak point of composite video signal, then the tangent line tangent with the peak point is drawn, finally tangent line is smoothly connected, it is described
Application program is generally mounted in the video frequency signal processing application program of test host.
Specifically, the video processing applications program can be matrix labotstory (MATLAB, Matrix
Laboratory)。
First determining module 32, for determining the first range value of the coenvelope line wave crest；
According to relevant criterion, testing the concrete signal of the bright gain inequality of color and the bright delay inequality of color in composite video signal is 20T
Impulse waveform, the definition of 20T pulse, in the waveform of 20T pulse, when amplitude reaches the half of maximum value, corresponding two
The distance between time point is 20T, and T is the time cycle；Specific to standard, for PAL, T 100ns；It is for NTSC, T
125ns。
In 20T pulse, coloration and luminance signal are Sine-squared waves, and carrier chrominance signal is superimposed upon in luminance signal.
Fig. 2 is the 20T impulse waveform in the present embodiment, and the π of ω=2 f, f are the carrier frequency of composite video signal.
In order to preferably observe 20T impulse waveform, it is assumed that the frequency of the composite video signal tends to just infinite, in this way,
The envelope of composite video signal becomes apparent from, and is specifically shown in Fig. 3~Fig. 6, and Fig. 3~Fig. 6 is that chromatic component and luminance component are Bu Tong special
Four seed types of sign, in which:
ACAnd AYThe respectively amplitude of chromatic component and luminance component,For the delay of coloration relative luminance.
Fig. 3 is characterized in: AC>AY,That is the amplitude of the chromatic component amplitude that is greater than luminance component, coloration is bright in advance
Degree；
Fig. 4 is characterized in: AC>AY,That is amplitude of the amplitude of chromatic component greater than luminance component, coloration lag
Brightness；
Fig. 5 is characterized in: AC<AY,That is the amplitude of the chromatic component amplitude that is less than luminance component, coloration is advanced
Brightness；
Fig. 6 is characterized in: AC<AY,That is amplitude of the amplitude of chromatic component less than luminance component, coloration lag
Brightness；
What above-mentioned figure was characterized in being obtained according to the shape qualitative analysis of envelope, analysis method is those skilled in the art
What member knew about, it does not repeat.
Further, envelope in Fig. 3 is individually shown, obtains envelope shown in Fig. 7.
First range value of the coenvelope line wave crest is the value of M shown in Fig. 7, determine first range value be for
The value range of luminance component amplitude and the delay of coloration relative luminance in composite video signal is determined in the next steps；
The method for determining first range value may include: the peak point for obtaining the coenvelope line, measure the peak
It is worth the amplitude of point, obtains first range value, i.e., the value of M shown in Fig. 7.
Second determining module 33, for determining brightness in the composite video signal according to first range value
The value range of component amplitude, and determine the value range of coloration relative luminance delay in the composite video signal；
After obtaining first range value, need to establish luminance component amplitude, coloration in the composite video signal
Component amplitude, coloration relative luminance are delayed and the relational expression of M, then determines therefrom that luminance component amplitude, coloration are relatively bright
The value range of delay is spent, specifically as follows:
According to the principle of composite video signal, it is known that the coloration and brightness waveform of composite video signal are respectively Sine-squared
Wave, therefore available AC、AYWithIt is expressed as the canonical function of the envelope of composite video signal as variable, specifically, in Fig. 7
Coenvelope line and lower envelope line use formula above-mentioned (1), (2) to indicate respectively.
In above-mentioned two formula, CVBS_t is coenvelope line, and CVBS_b is lower envelope line, ACAnd AYRespectively chromatic component and bright
The amplitude of component is spent,For the delay of coloration relative luminance.
According to formula (1), it is assumed that the delay of coloration relative luminance is zero, i.e.,It can then obtain: M=AY+Ac；
And Ac is Sine-squared, is greater than or equal to zero, so AYIt is not more than M, therefore A can be obtainedYValue range be
0 arrives M, i.e., the value range of luminance component amplitude is zero to first range value in the described composite video signal；
By the characteristics of SIN function it is found that in formula (1)Period is 2 π, andFor coloration relative luminance
Delay, it is possible to it is advanced, it is also possible to lag, therefore settableValue range be and to be less than or wait more than or equal to-π
In π,Value range can be expressed as [- π, π].
The third determining module 34, for opposite to the luminance component amplitude and coloration in corresponding value range
Brightness delay difference assignment, the assignment is substituted into and is delayed with the luminance component amplitude, the coloration relative luminance as variable
Coenvelope line function in, and determine substitute into assignment coenvelope line function wave crest the second range value；
Specifically, distinguish to be delayed in corresponding value range to the luminance component amplitude and coloration relative luminance
After assignment, can determine that the second range value of the wave crest of the function of the coenvelope line, need to the envelope canonical function into
Row transformation obtains the relationship of luminance component amplitude and coloration relative luminance delay and the second range value of the envelope wave crest
Formula；
Certainly, during assignment tentative calculation, it is also necessary to some other formula, it is clear in order to describe, it will first calculate
All formula used in journey are first derived one by one:
Notice that formula (1) is there are a maximum, and there are a maximum and minimums for formula (2) as ω t ∈ [0, π].
Therefore respectively to formula (1) and formula (2) to t derivation, formula (3) and formula (4) are obtained.
When formula (1) and formula (2) reach maximum value or minimum value, formula (3) and formula (4) are respectively equal to 0, obtain (5) and formula
(6)。
If the t for meeting formula (5) is tt, the t for meeting formula (6) is tb1And tb2；According to tb1And tb2Relationship can obtain formula (7):
In conjunction with Fig. 7, by tt、tb1、tb2Formula (1) and formula (2) are substituted into formula (7), obtains formula (8), (9), (10):
Formula (9) is added to obtain formula (11) with formula (10):
Then formula (12) are derived by by formula (5):
Finally obtain formula (13):
Similarly, formula (14) can be derived by by formula (6):
After deriving above-mentioned formula, to AYWithAssignment is distinguished in value range, is found out accordingly according to assignment with formula (11)
AC；Acquire ACAfterwards, by AC、AYWithSubstitution formula (13) finds out ω tt；
The ω t that will be acquiredtSubstitution formula (8), determines the second range value of the coenvelope line, that is, calculates the substitution
The maximum value of the function of the coenvelope line of assignment, is denoted as M ',
To AYWithContinue assignment in the value range of setting, obtains the second range value of multiple coenvelope lines；
4th determining module 35, for being less than preset value when second range value and the first range value difference
When, the color of the composite video signal is determined by each assignment that the luminance component amplitude and the coloration relative luminance are delayed
Bright gain inequality and the bright delay inequality of color.
When second range value and the first range value difference are less than preset value, pass through the luminance component amplitude
The bright gain inequality of color and the bright delay inequality of color of the composite video signal are determined with each assignment of coloration relative luminance delay；
Specifically, it is calculated by formula (15), (16):
The result that formula (15) acquires is the bright gain inequality of color, unit %；
The result that formula (16) acquires is the bright delay inequality of color, unit ns；If calculated result is negative, illustrate that coloration lags,
If calculated result is positive, illustrate that coloration is advanced；
Wherein, N is constant, because being 20T pulse, taking 20, T is the time cycle；Specific to standard, for PAL, T
For 100ns；For NTSC, T 125ns；
Default difference value is to be determined according to the requirement of composite video decoding chip, is not repeated.
Further, in order to keep calculated result more acurrate, multiple waveforms can be extracted from composite video signal, are counted respectively
Calculate the bright gain inequality of color and the bright delay inequality of color；
Specifically, the respective coenvelope of the multiple composite video signal obtained respectively based on multiple composite video signals
Line determines the bright gain inequality of the respective color of the multiple composite video signal and the bright delay inequality of color based on each coenvelope line respectively；
The bright gain inequality of multiple colors and the bright delay inequality of color are averaged respectively respectively；
Using the average value as the bright gain inequality of the color of the composite video signal and the bright delay inequality of color
More specifically, according to composite video signal principle, it is known that the waveform of 20T pulse be initial phase be zero degree, 90 degree,
180 degree, the four of 270 degree kinds of waveform cycles, wherein zero degree, 180 degree and 90 degree, 270 degree of shape are just the same, only wave crest wave
Paddy is contrary, as long as therefore calculate the index of zero degree and 90 degree of both waveforms, and be averaged, it may be assumed that
The composite video signal for being zero according to initial phase calculates the bright gain inequality of the first color and the bright delay inequality of the first color:
The composite video signal for being 90 degree according to initial phase, calculates the bright gain inequality of the second color and the bright delay inequality of the second color；
The bright gain inequality of color is obtained according to the average value of the bright gain inequality of the first color and the bright gain inequality of the second color, it is bright according to the first color
The average value of delay inequality and the bright delay inequality of the second color obtains the bright delay inequality of color.
In practical applications, the acquisition module 31, the first determining module 32, the second determining module 33, third determine mould
Block 34 and the 4th determining module 35 can be believed by the central processing unit (CPU), microprocessor (MPU), number for being located at test host
Number processor (DSP) or field programmable gate array (FPGA) etc. are realized.
It should be understood by those skilled in the art that, the embodiment of the present invention can provide as method, system or computer program
Product.Therefore, the shape of hardware embodiment, software implementation or embodiment combining software and hardware aspects can be used in the present invention
Formula.Moreover, the present invention, which can be used, can use storage in the computer that one or more wherein includes computer usable program code
The form for the computer program product implemented on medium (including but not limited to magnetic disk storage and optical memory etc.).
The present invention be referring to according to the method for the embodiment of the present invention, the process of equipment (system) and computer program product
Figure and/or block diagram describe.It should be understood that every one stream in flowchart and/or the block diagram can be realized by computer program instructions
The combination of process and/or box in journey and/or box and flowchart and/or the block diagram.It can provide these computer programs
Instruct the processor of general purpose computer, special purpose computer, Embedded Processor or other programmable data processing devices to produce
A raw machine, so that being generated by the instruction that computer or the processor of other programmable data processing devices execute for real
The device for the function of being specified in present one or more flows of the flowchart and/or one or more blocks of the block diagram.
These computer program instructions, which may also be stored in, is able to guide computer or other programmable data processing devices with spy
Determine in the computer-readable memory that mode works, so that it includes referring to that instruction stored in the computer readable memory, which generates,
Enable the manufacture of device, the command device realize in one box of one or more flows of the flowchart and/or block diagram or
The function of being specified in multiple boxes.
These computer program instructions also can be loaded onto a computer or other programmable data processing device, so that counting
Series of operation steps are executed on calculation machine or other programmable devices to generate computer implemented processing, thus in computer or
The instruction executed on other programmable devices is provided for realizing in one or more flows of the flowchart and/or block diagram one
The step of function of being specified in a box or multiple boxes.
The foregoing is only a preferred embodiment of the present invention, is not intended to limit the scope of the present invention, it is all
Made any modifications, equivalent replacements, and improvements etc. within the spirit and principles in the present invention, should be included in protection of the invention
Within the scope of.
Claims (12)
1. a kind of composite video signal quality index determines method, which is characterized in that the described method includes:
The coenvelope line for obtaining composite video signal, determines the first range value of the coenvelope line wave crest；
According to first range value, the value range of luminance component amplitude in the composite video signal is determined, and determine institute
State the value range that coloration relative luminance is delayed in composite video signal；
To the luminance component amplitude and coloration relative luminance delay difference assignment in corresponding value range, by the assignment
It substitutes into and determines and substitute into the coenvelope line function of variable with the luminance component amplitude, coloration relative luminance delay
Second range value of the wave crest of the function of the coenvelope line of assignment；
When second range value and the first range value difference are less than preset value, pass through the luminance component amplitude and institute
Each assignment for stating the delay of coloration relative luminance determines the bright gain inequality of the color of the composite video signal and the bright delay inequality of color.
2. the method according to claim 1, wherein the coenvelope line for obtaining composite video signal, comprising:
The peak point in the composite video signal each period is obtained, the peak point is connected, forms coenvelope line.
3. according to the method described in claim 2, it is characterized in that, the first amplitude of the determination coenvelope line wave crest
Value, comprising:
The peak point for obtaining the coenvelope line measures the amplitude of the peak point, obtains first range value.
4. the method according to claim 1, wherein luminance component width in the determination composite video signal
The value range of degree, comprising:
According to first range value, the value range for determining luminance component amplitude in the composite video signal is zero described in
First range value；
The value range that coloration relative luminance is delayed in the determination composite video signal, comprising:
In the composite video signal coloration relative luminance be delayed range be more than or equal to-π, and be less than or equal to π.
5. the method according to claim 1, wherein the wave of the function of the determining coenvelope line for substituting into assignment
Second range value at peak, including；
Based on the function of the coenvelope line for substituting into assignment, the maximum of the function of the coenvelope line for substituting into assignment is calculated
Value, is determined as second range value for maximum value calculated.
6. the method according to claim 1, wherein the method also includes；
Based on the respective coenvelope line of the multiple composite video signal that multiple composite video signals obtain respectively, on each
Envelope determines the bright gain inequality of the respective color of the multiple composite video signal and the bright delay inequality of color respectively；
The bright gain inequality of multiple colors and the bright delay inequality of color are averaged respectively respectively；
Using the average value as the bright gain inequality of the color of the composite video signal and the bright delay inequality of color.
7. a kind of composite video signal quality index determining device, which is characterized in that described device includes obtaining module, first really
Cover half block, the second determining module, third determining module and the 4th determining module；Wherein,
The acquisition module, for obtaining the coenvelope line of composite video signal；
First determining module, for determining the first range value of the coenvelope line wave crest；
Second determining module, for determining luminance component width in the composite video signal according to first range value
The value range of degree, and determine the value range of coloration relative luminance delay in the composite video signal；
The third determining module, for prolonging in corresponding value range to the luminance component amplitude and coloration relative luminance
When distinguish assignment, the assignment is substituted into and is delayed as the upper packet of variable with the luminance component amplitude, the coloration relative luminance
In winding thread function, and determine the second range value for substituting into the wave crest of the function of coenvelope line of assignment；
4th determining module, for leading to when second range value is less than preset value with the first range value difference
Each assignment for crossing the luminance component amplitude and coloration relative luminance delay determines the bright increasing of the color of the composite video signal
Beneficial difference and the bright delay inequality of color.
8. device according to claim 7, which is characterized in that the acquisition module is also used to:
The peak point in the composite video signal each period is obtained, the peak point is connected, forms coenvelope line.
9. device according to claim 8, which is characterized in that first determining module is also used to:
The peak point for obtaining the coenvelope line measures the amplitude of the peak point, obtains first range value.
10. device according to claim 7, which is characterized in that second determining module is also used to:
According to first range value, the value range for determining luminance component amplitude in the composite video signal is zero described in
First range value；
Second determining module is also used to determine the value range that coloration relative luminance is delayed in the composite video signal: institute
Stating the range that coloration relative luminance in composite video signal is delayed is and to be less than or equal to π more than or equal to-π.
11. device according to claim 7, which is characterized in that the third determining module is also used to:
Based on the function of the coenvelope line for substituting into assignment, the maximum of the function of the coenvelope line for substituting into assignment is calculated
Value, is determined as second range value for maximum value calculated.
12. device according to claim 7, which is characterized in that the 4th determining module is also used to:
Based on the respective coenvelope line of the multiple composite video signal that multiple composite video signals obtain respectively, on each
Envelope determines the bright gain inequality of the respective color of the multiple composite video signal and the bright delay inequality of color respectively；
The bright gain inequality of multiple colors and the bright delay inequality of color are averaged respectively respectively；
Using the average value as the bright gain inequality of the color of the composite video signal and the bright delay inequality of color.
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| CN104320655A (en) * | 2014-11-11 | 2015-01-28 | 杭州士兰微电子股份有限公司 | Video decoding chip testing device and method |
| WO2016078262A1 (en) * | 2014-11-19 | 2016-05-26 | 深圳市中兴微电子技术有限公司 | Measurement method and apparatus for composite video broadcast signal quality and storage medium |
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| CN102547309A (en) * | 2011-11-24 | 2012-07-04 | 苏州希图视鼎微电子有限公司 | Detection calculating method and device for frequency shift of composite video broadcast signal (CVBS) |
| CN104320655A (en) * | 2014-11-11 | 2015-01-28 | 杭州士兰微电子股份有限公司 | Video decoding chip testing device and method |
| WO2016078262A1 (en) * | 2014-11-19 | 2016-05-26 | 深圳市中兴微电子技术有限公司 | Measurement method and apparatus for composite video broadcast signal quality and storage medium |
| CN105681780A (en) * | 2014-11-19 | 2016-06-15 | 深圳市中兴微电子技术有限公司 | Method and apparatus for measuring quality of composite video broadcast signal |
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Application publication date: 20180116 Assignee: Xi'an Chris Semiconductor Technology Co. Ltd. Assignor: SHENZHEN ZTE MICROELECTRONICS TECHNOLOGY CO., LTD. Contract record no.: 2019440020036 Denomination of invention: Method and device for determining quality index of composite video signal Granted publication date: 20190430 License type: Common License Record date: 20190619 |
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