JP2947651B2 - Automatic video equalizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic image equalizer for automatically equalizing a color image signal caused by linear and non-linear characteristics of a transmission path without manual operation.

[0002]

2. Description of the Related Art A video signal of a color television or the like captured by a television camera or the like at a remote location is transmitted to a broadcasting station having broadcasting facilities using a microwave line. In a broadcasting station, a received color video signal is transmitted after correcting a distortion caused by linear and non-linear characteristics of a transmission line formed by a microwave line, equalizing the distortion to a normal value, and transmitting the corrected color video signal.

[0003] A distortion correction method conventionally performed in a broadcasting station will be described with reference to FIG. FIG. 11 is a configuration diagram of a conventional example. In FIG. 11, reference numeral 201 denotes a luminance level adjusting unit which adjusts and outputs the luminance level of an input video signal. 2
Reference numeral 02 denotes a chroma level adjusting unit that adjusts the chroma level of an input video signal and outputs the adjusted signal. A hue adjustment unit 203 adjusts the hue of the input video signal and outputs the adjusted signal. A waveform monitor 204 monitors the waveform of the video signal. 2
Reference numeral 05 denotes a vector scope, which displays the amplitude and phase of a subcarrier for transmitting a color signal.

[0004] Before transmitting a video signal for broadcasting, a color bar signal is transmitted to equalize the distortion of the transmission path. The color bar signal is a predetermined signal for testing the transmission path, and the received color bar signal is observed by the waveform monitor 204 and the vector scope 205.

[0005] Observing the luminance level on the waveform monitor 204,
As a result of the observation, if the measured value does not match the specified value, the adjuster (not shown) of the brightness level adjusting unit 201 is manually changed to match the specified value. The chroma level is monitored by the waveform monitor 204 or the vector scope 205. If the chroma level does not match the specified value, the chroma level adjuster 20
The regulator (not shown) 2 is changed to match the specified value. The hue is observed by the vector scope 205, and when the hue does not match the specified phase, the adjuster (not shown) of the hue adjusting unit 203 is changed to match the specified phase.

[0006]

As described above, conventionally, when an image is transmitted from a remote place via a microwave line, a color bar signal is transmitted before the image is transmitted, and the distortion generated in the transmission line is manually reduced. The correction was made via

For this reason, it takes a long time to perform the correction, and today, depending on the television broadcast program, a video signal sent from a remote place may be switched and broadcast in a unit of several minutes. However, the present invention involves a great deal of effort to correct and sometimes a risk of broadcasting at an incorrect level due to human error.The present invention reduces distortion generated on a transmission line from a color bar signal transmitted from a remote place. It is an object of the present invention to provide an automatic video equalization device that performs automatic equalization.

[0008]

Means adopted by the present invention to solve the above-mentioned problems will be described. In a video equalizer that adjusts an input video signal with a luminance level adjustment unit, a hue adjustment unit, and a chroma level adjustment unit to equalize distortion, it is determined that the input video signal is a color bar signal by a change point of the luminance signal level. A color bar signal identifying means for identifying from a time interval, and when the input video signal is determined to be a color bar signal by the color bar signal identifying means, detecting a luminance level error of the color bar signal with respect to a specific color signal; A brightness level error detecting unit that returns to the brightness level adjusting unit;
A hue error detecting means for detecting a difference between a ratio of the I signal for the specific color and the Q signal and a specified value of the ratio and feeding back to the hue adjusting unit; an I signal, a Q signal or an I signal for the specific color;
A chroma level error detecting means for detecting a difference between one of the sum of the signal and the Q signal and a specified value for each of the sums and returning the result to the chroma level adjusting unit.

[0009]

The color bar signal discriminating means examines the change point of the luminance signal level, and identifies the color bar signal based on the time interval between the change points. If the input video signal is identified as a color bar signal by the color bar signal identifying means, the luminance level error detecting means detects a luminance level error of the color bar signal with respect to the specific color signal and returns to the luminance level adjusting unit. .

The hue error detecting means calculates the ratio between the I signal and the Q signal with respect to the specific color, detects the difference between the specified value of the ratio between the I signal and the Q signal, and returns the difference to the hue adjustment unit. Further, the chroma level error detecting means may select any one of the I signal, the Q signal, or the sum of the I signal and the Q signal for the specific color,
A difference between a specified value of each of the I signal, the Q signal, or the sum of the I signal and the Q signal for the specific color is detected and fed back to the chroma level adjustment unit.

As described above, the input image signal is identified as a color bar signal from the time interval of the change point of the luminance level, and when the input image signal is identified as the color bar signal, the specific color signal is identified. The specified value and error of the luminance level are detected and fed back to the luminance level adjusting unit, and the I signal and Q of the specific color are detected.
An error from a specified value of the ratio of the signal to the specified value is fed back to the hue adjustment unit, and an error between the specified value of the I signal, the Q signal of a specific color, or the sum of the I signal and the Q signal is detected. Is detected and fed back to the chroma level adjustment unit, so that the distortion generated in the transmission path can be automatically equalized in a short time without requiring any manual operation.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is an explanatory diagram of a color bar signal used in the present invention, and FIG.
FIG. 4 is an operation explanatory diagram of a specific example of the luminance / chroma signal separating unit, FIG. 5 is an operation flowchart of the color bar signal identifying unit, and FIG. 6 is an operation flowchart of the luminance level error detecting unit. 7 is a specific example of the I / Q separation unit, FIG. 8 is an operation flowchart of the hue error detection unit, FIG. 9 is an operation flowchart of the chroma level error detection unit, and FIG. 10 is an operation flowchart of the embodiment.

First, a color bar signal used in the present invention will be described with reference to FIG. FIG. 2 shows an 8-color color bar signal, and white (W), yellow (YL), cyan (CY), green (G), and magenta (M) are provided in 52 and 65 μs between horizontal synchronization signals.
G), red (R), blue (BL) and black (BLK) are transmitted at equal intervals.

In the transmission of a color image, these colors are converted into a luminance signal (E _Y ), an I signal (E _I ) and a Q signal as shown in FIGS. 2 (b), 2 (c) and 2 (d). The signal is transmitted by a combination of the three signals (E _Q ). The frequency f _{SC of the} I signal and the Q signal is 3.579.
The amplitudes of two orthogonal subcarriers of 545 MHz are amplitude-modulated by E _I and E _Q , respectively, and transmitted.

Therefore, the color bar signal E _S (t) is expressed as E _S (t) = E _Y (t) + E _CH (t) (1) = E _Y (t) + E _I (t) cos (2πf _SC t + 33) °) + E _Q (t) sin (2πf _SC t + 33 °) (2), and E _CH (t) in equation (1) is called a chroma signal.

Further, the chroma signal of the color video signal
A sub-carrier 2sin (2 sin (2) that is not amplitude-modulated between the horizontal synchronizing signal and the white of the color bar signal is provided as a phase reference of the sub-carrier necessary for separating the signal and the Q signal.
πf _SC t) is inserted, which is called a color burst signal.

There are also seven color bar signals, and in the case of the seven color bar signal, black disappears, and
2.65 μs is divided into seven equal parts, and each color is transmitted. Also, E _Y = 1.
There are also cases of 00 and 1.33.

Next, the configuration of the embodiment will be described with reference to FIG. In FIG. 1, a luminance level adjusting unit 201, a chroma level adjusting unit 202, and a hue adjusting unit 203 are as described in FIG. Reference numeral 1 denotes an analog-to-digital converter (A / D), which extracts the above-described color burst signal, samples the color bar signal at a frequency of four times the frequency f _SC of the subcarrier, and converts it to a digital signal. .

Reference numeral 2 denotes a memory for storing one scanning line of the color bar signal converted into a digital signal by the A / D 1. 3 is a luminance / chroma signal separating means, 4 is an I / Q separating means, 5 is a color bar signal identifying means, 6 is a luminance level error detecting means, 7 is a hue error detecting means, 8 is a chroma level error detecting means, and 9- Reference numerals 1 to 3 are digital / analog converters (D / A).

As shown in FIG. 3, the luminance / chroma signal separating means 3 comprises a two-sampling delay circuit 31, an adder 3
2, a subtractor 33, 1/2 dividers 34 and 35, a band-pass filter (BPF) 37, a luminance memory 36, and a chroma memory 38. The luminance / chroma signal separation means, as shown in FIG.
The stored data is sequentially read from the memory 2 which is sampled by a factor of 2, converted into a digital signal and stored, and a two-sampling delay circuit 31 and an adder 32
And input to the subtractor 33. In the two-sampling delay circuit 31, the data read from the memory 2 is delayed by two sample times and input to the adder 32 and the subtracter 33, as shown in FIG.

The signals are added by an adder 32 and are divided by a 1/2 divider 34
4C, the luminance signal is obtained without the chroma signal, as shown in FIG.
6 is stored. Further, the value is subtracted by the subtracter 33, and
B, which is divided by the divider 35 and passes the subcarrier
The chroma signal is separated by passing through the PF 37 and stored in the chroma memory 38.

When the luminance signal and the chroma signal are separated by the luminance / chroma signal separating means 3, the color bar signal identifying means 5 starts operation to identify whether or not the input video signal is a color bar signal. . The processing shown in FIG. 5 is executed by the CPU 10 in the color bar signal identification means 5.

Process S101 In process S101, counters A and B (not shown) are reset. Processing S102 and S103 The first data and the next data are read from the luminance memory 36 storing the luminance signal.

Step S104 One is added to the count value of the counter A. Process S105 The difference between the data value read this time and the data value read from the previous brightness memory is determined, and it is determined whether or not the difference is equal to or greater than X. .

That is, in step S105, a change point of the color signal is detected. If a color bar signal, as described in FIG. 2, the luminance signal E _Y is initially white is sent,
E _Y changes from 0 to 1.00 or 1.33. The next time changes to yellow than white, E _Y 1.33 or 1.00
To 0.89. Cyan than sequentially yellow, E _Y each time you change to green than cyan changes. Therefore, for example, X is set to 0, which is the smallest change value when the color changes.
11 and set the difference between the read data values to 0.
If it is greater than 55, it is determined to be a change point of the color signal.

Process S106 If the decision result in the process S105 is YES, in a process S106, the count value of the counter A is recorded in a memory (not shown). Process S107 One is added to the count value of the counter B.

Process S108 It is determined whether or not the data stored in the luminance memory 36 is the last data. If YES, the process goes to the process S109. If NO, the process goes to the process S103 to repeat the processes S103 to S108. .

Process S109 The count value of the counter B is checked to determine whether the count value is 7 or 8, and if YES, the process proceeds to Step S110.
On the other hand, in the case of NO, the process moves to step S112. That is, in step S105, the color change point indicating that the color bar signal is detected is detected and detected. However, even when a general video signal is input, there is a signal whose data value difference is equal to or larger than X. Therefore, in step S109, if the signal is a color bar signal,
As described with reference to FIG. 2, if the color bar signal is an eight-color color bar signal, there are eight change points, and if the color bar signal is a seven-color color signal, there are seven change points. For example, it is determined that the color bar signal is not a color bar signal, and the other is not a color bar signal.

Process S110 In process S106, data is read from the memory in which the count value of the counter A is recorded, and it is determined whether or not the time interval in which the data is recorded is within 5.5 μs to 8.5 μs. If YES, the process proceeds to step S111, and if NO, the process proceeds to step S112.

That is, in the process S110, if the color bar signal is an 8-color bar signal, the time interval at the time of change is 6.5812 μs,
Since the time is 7.5214 μs for seven colors, if the common value of these time intervals is between 5.5 μa and 8.5 μs, the color bar signal is determined. Judgment value 5.
5 to 8.5 μs is one example, and can be changed as needed.

The time measurement of 5.5 μs and 8.5 μs is performed by the difference between the data values recorded in the memory.
That is, the data stored in the luminance memory 36 is data sampled at a frequency four times the subcarrier frequency f _SC . Since f _SC is 3.579545 MHz, the sampling interval is 6.98413 × 10 ⁻² μs. Therefore, if the difference between the data values recorded in the memory is 79, the time is 5.5 μs, and if the difference between the data values is 122, the time is 8.5 μs. 5.5 μs to 8.5 of processing S110
The determination as to whether it is within μs is made based on whether or not the difference between the data values recorded in the memory is within 79 to 122.

Process S111 If the decision result in the process S110 is YES, the process S111
Is determined to be a color bar signal, and all the processing ends. Process S112 When the determination results of processes S109 and S110 are NO,
In step S112, it is determined that the received signal is not a color bar signal, and all the processing ends.

Next, the operation of the luminance level error detecting means will be described with reference to the flowchart of FIG. Process S201 In process S201, the CPU 10 first reads the white (W), yellow (YL), and magenta (MG) data stored in the chroma memory 38 of the luminance / chroma signal separation means 3.

Processing S202 (W-YL) / (YL-CY) = Y is calculated from the data of W, YL and MG read in processing S201. Processing S203 It is determined whether or not Y calculated in processing S202 is greater than 1.46. If the determination result is YES, processing S204 is performed.
On the other hand, in the case of NO, the process moves to step S208.

That is, in step S203, as described with reference to FIG. 2, the white level of the input color bar signal becomes E _Y =
It is determined whether the value is 1.33 or 1.00. E
_{If Y} = 1.33, Y = 2.35, and if E _Y = 1.00, Y = 0.58. If Y is larger than the median value of 1.46, white E _Y is 1.33 and small. Then, it is determined that the color bar signal is 1.00.

Steps S204 and S208 In the step S204, E is a 100% standard value of the white level.
The difference E between the value corresponding to _Y = 1.33 and W is calculated. Processing S208 is a 75% standard value of the white level, E _Y = 1.0.
The difference E between the value corresponding to 0 and W is calculated.

Steps S205 and S209 In the step S205, E and E _Y =
It is determined whether the ratio with respect to the value corresponding to 1.33 is greater than or equal to Y%, and if the determination result is YES, processing S206 is performed.
If the determination is NO, the process proceeds to step S207.

In step S209, it is determined whether or not the ratio of E calculated in step S208 to the value corresponding to E _Y = 1.00 is greater than Y%. If the determination result is YES, the process proceeds to step S209. If NO in step S210, the process proceeds to step S211. Processing S206 and S210 In processing S206, E calculated in processing S204, processing S2
In step 10, the correction value Y ₁ (Y ₁
> 1.0) multiplied by the, to calculate the E _1.

Processing S207 and S211 In processing S207, E calculated in processing S204, processing S2
In step 11, the correction value Y ₂ (Y ₂
<1.0) to calculate E ₂ . Processing S212 In processing S212, processing S206, S207, S210
Or has been the E ₁ or E ₂ calculated in S211, it is added to the data value stored in the unillustrated correction value memory.

Step S213 In step S212, the correction value stored in the correction value memory is stored.
Then, the data value is output to the D / A 9-1, and the process ends.
In the processing S205 and S209, whether the error E is larger than Y%
Judge whether or not it is large₁, If small, E to Y_Two
For multiplying by the correction value memory in step S212
Is, if the allowable value of the error E is 2%,
If it is large, quickly bring the brightness level closer to the normal level.
Correction value Y greater than 1.00₁And E is 2
% And within the tolerance, a slight error
Constant brightness rather than changing the brightness level by correcting the difference
So that the level is output from the luminance level adjustment unit 201
To stabilize the output level.
Nay _TwoIs multiplied.

In the embodiment, the luminance level error is detected by using the level values of W, YL and CY. However, the error can be detected by the same processing even if other color levels are used. Can be. Next, referring to FIG.
The Q separating means 4 will be described.

In FIG. 7, 41 and 42 are multiplication circuits, 43 and 44 are low-pass filters (LPF), 47
Is an I memory, 48 is a Q memory, 46 is an oscillator, 45 is π
/ 2 phase shifter. Data is sequentially read and input to the multiplication circuits 41 and 42 from the chroma memory 38 in which the chroma signal data of the luminance / chroma signal separation means 3 is stored.

That is, the signal read from the chroma memory 38 can be expressed as a continuous function to facilitate the explanation. From the equation (2), E _CH (t) = E _I (t) cos (2πf _SC t + 33 ° + α) ) + E _Q (t) sin (2πf _SC t + 33 ° + α) (3) is input.

In the OSC 46, as described with reference to FIG.
Prior to the color bar signal, synchronization is obtained from the color burst signal cos (2πf _SC t) which provides a phase reference of the chroma signal, and a frequency sin (2πf _SC t + 33 °) is oscillated and input to the multiplication circuit 41. On the other hand, the multiplication circuit 42
The oscillation output from SC46 is shifted by π / 2 phase shifter to π / 2.
The phase is shifted and sin (2πf _SC t + 33 °) is input.

Therefore, the output E _CI of the multiplication circuit 41 is E _CI = E _CH (t) cos (2πf _SC t + 33 °) = E _I (t) [cos (α) + cos (4πf _SC t + 66 ° + α)] / 2 + E _Q (t) [sin (α) + sin (4πf _SC t + 66 ° + α)] / 2 (4) is output. Here, α is the rotation angle due to the distortion received on the transmission path.

The LPF 43 removes the 4f _SC component of the equation (3), and the I memory 47 stores I = [E _I (t) cos (α) + E _Q (t) sin (α)] / 2 (5) Is stored. Similarly, multiplication is performed by the multiplication circuit 42,
The 4f _SC component is removed by the LPF 44, and Q = [− E _I (t) sin (α) + E _Q cos (α)] / 2 (6) is stored in the Q memory 48.

Next, the operation of the hue error detecting means will be described with reference to the flowchart of FIG. Processing S301 In processing S301, the CPU 10 first sets the IQ separation means 4
Of data stored in the I memory 47 and the Q memory 48 for yellow.

Process S302 The specified value -I / Q = E is calculated. The specified value is given by equation (5)
And the value of the I / Q when the alpha = 0 in (6), E _I is 0.32, E _Q is for yellow than Figure 2 -
Since it is 0.31, the specified value is -1.032. However, the I / Q undergoes rotation with a hue of α on the transmission path.
The value is different from 032.

Processing S303 In processing S303, E is calculated from E calculated in processing S302.
Is greater than the allowable range of H degrees, and if the predetermined result is Y
If it is ES, the process proceeds to step S304, and if it is NO, the process proceeds to step S30.
Move to 5.

The determination as to whether or not the degree is greater than the allowable range of H degrees is, for example, if H is set to 2 degrees, α in Equations (5) and (6) is used.
Is substituted by 2 degrees to obtain an I / Q. When α is +2 degrees, the result is −0.9626, E is −0.0694, and α is −
In the case of twice, I / Q becomes -1.1071 and E is 0.0
751. Therefore, E calculated in step S302
If is within the range of -0.0694 to 0.0751, the process moves to step S305, and if it is outside the range, the process moves to step S304.

Steps S303 and S305 In step S303, E calculated in step S302 is replaced by H ₁ (H
₁ > 1.00) to calculate E ₁ , and process S305
Then, E is multiplied by H ₂ (H ₂ , <1.00) to calculate E ₂ , and the process proceeds to S306.

[0052] is calculated in the process S306 processing S303 or S305 the E ₁ or E
₂ is added to the data value stored in the correction value memory (not shown). Processing S307 In processing S306, the data value added and stored in the correction value memory is output to the D / A 9-3, and the processing ends.

The reason why E processing S303, it is determined whether large or not than H level, adding the H ₁ to E if large, also the data value of the correction value memory by multiplying of H ₂ to H if small Is for the same reason as described in the luminance level error detecting means. In the above-described embodiment, the hue error is detected for yellow, but the detection can be performed for other colors.

Next, the operation of the chroma level error detecting means will be described with reference to the flowchart of FIG. Processing S401 In processing S401, the CPU 10 first reads data for yellow from the I memory 47 and the Q memory 48.

Processing S402 In processing S402, a specified value− (I + Q) = E is calculated. The chroma signal E _CH (t) is expressed by equation (3), and its level V _CH (t) is V _CH (t) = (E _I ² (t) + E _Q ² (t)) ^0.5 ... (7) And E _I and E _Q for yellow are V _CH = 0.446 since E _I = 0.32 and E _Q = −0.31 as described with reference to FIG. However, it is difficult to calculate the chroma level from equation (7), and the present invention calculates the chroma level by the method described below.

That is, the chroma signal is separated by the IQ separation means 4.
Are separated into an I signal and a Q signal, and the data values stored in the I memory 47 and the Q memory 48 are respectively
The values shown in Expressions (5) and (6) are stored.
Therefore, when an error is detected by the above-described hue error detecting means 7 and is fed back to the hue adjusting section 203 to set α = 0, I and Q in equations (5) and (6) become I = E _I (t) / 2 (8) Q = E _Q (t) / 2 (9), and the specified value of the chroma level expressed by the equation (7) is I + Q
The specified value represented by can be substituted. The specified value when indicated by I + Q is E _I = 0.32 for yellow.
Specified value since it is E _Q = -0.31 is 0.005.

As the data values for yellow stored in the I memory 47 and the Q memory 48, the chroma signal level changes due to the distortion of the transmission line, and the data values with the phase rotation α are stored. When the error is fed back by the hue error detecting means 7 and α = 0, the above-mentioned specified value − (I + Q) = E is calculated, and when the feedback is made so that E becomes 0, a specified chroma level can be output. it can.

Process S403 It is determined whether or not E calculated in process S402 is larger than C% of the allowable value. If larger, the process proceeds to step S404, and if smaller, the process proceeds to step S405. Processing S404 and S405 In processing S404, E calculated in processing S402 is added to C
₁ (C ₁ > 1.0), and C ₂ (C 1
₁ <1.0) and the process proceeds to step S406.

[0059] is calculated in the process S406 processing S404 or S405 the E ₁ or E
₂ is added to the data value stored in the correction value memory (not shown). Process S407 The data value added and stored in the correction value memory in the process S406 is output to the D / A 9-2, and the process ends.

In the above-described embodiment, the chroma level error is detected for yellow, but the same can be performed for other colors. Further, although the chroma level error is performed for I + Q, a similar chroma level error can be detected by using only the I signal or only the Q signal.

Finally, the operation of the present invention will be described with reference to the flowchart of FIG. Processing S501 In processing S501, the CPU 10 loads the video signal converted into a digital signal by the A / D 1 into the memory 2 for one line.

Processing S502 The luminance / chroma signal separating means 3 separates the luminance signal and the chroma signal. Process S503 The color bar signal identification means 5 determines whether the input image is a color bar signal or not.
In the case of YES, the process proceeds to step S504, and in the case of NO, the process proceeds to step S501, and steps S501 to S503 are repeated.

Processing S 504 The brightness level error is detected by the brightness level error detection means 6 described above, output to the D / A 9-1 and output to the brightness level adjustment unit 201. Process S505 The I / Q separating means 4 described above converts the chroma signal into I
Separate the signal and the Q signal.

Processing S 506 The hue error detecting means 7 detects the hue error, outputs the hue error to the D / A 9-3, and outputs the hue error to the hue adjustment section 203. Process S507 The chroma level error detecting means 8 detects a chroma level error, outputs the same to the D / A 9-2, and outputs the same to the chroma level adjuster 202.

When the process of step S507 is completed, the process returns to step S501, and steps S501 to S507 are repeated.
As described above, one embodiment of the present invention has been described, but the present invention is not limited to this embodiment, and various modifications in accordance with the gist of the invention are possible.

[0066]

As described above, according to the present invention, the following effects can be obtained. The input video signal is identified as a color bar signal from the time interval of the change point of the luminance level, and when the input video signal is identified as the color bar signal, the specified value and the error of the specific color luminance level are determined. Detected and fed back to the luminance level adjusting unit, detects an error between the specified value of the ratio of the I signal and the Q signal of the specific color, and feeds back to the hue adjusting unit. Alternatively, since an error between any one of the specified values of the sum of the I signal and the Q signal is detected and fed back to the chroma level adjustment unit, the error automatically occurs on the transmission line in a short time without any need for human intervention. Distortion can be equalized.

Since the identification of the color bar signal, the detection of the luminance level error, the detection of the hue error, and the detection of the chroma level error are processed by a signal corresponding to one scanning line of the input video signal, the memory can be reduced and the apparatus can be simplified. Can be If the detected error value is within the allowable value, the error value is multiplied by a correction value smaller than 1.0.
Since the output is multiplied by a larger correction value, the time for equalizing the distortion is reduced, and the video output signal within the allowable value can be stabilized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a color bar signal.

FIG. 3 is a specific example of a luminance / chroma signal separation unit of the embodiment.

FIG. 4 is an operation explanatory diagram of a specific example of a luminance / chroma signal separation unit.

FIG. 5 is an operation flowchart of a color bar signal identification unit of the embodiment.

FIG. 6 is an operation flowchart of a luminance level error detecting unit of the embodiment.

FIG. 7 is a specific example of the IQ separation means of the embodiment.

FIG. 8 is an operation flowchart of a hue error detection unit of the embodiment.

FIG. 9 is an operation flowchart of the chroma level error detecting means of the embodiment.

FIG. 10 is an operation flowchart of the embodiment.

FIG. 11 is a configuration diagram of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Analog-to-digital converter (A / D) 2 Memory 3 Luminance / chroma signal separation means 4 IQ separation means 5 Color bar signal identification means 6 Luminance level error detection means 7 Hue error detection means 8 Chroma level error detection means 9 Digital Analog converter (D / A) 10 Processor (CPU) 31 2 sample delay circuit 32 Adder 33 Subtractor 34, 35 1/2 divider 36 Luminance memory 37 Band-pass filter (BPF) 38 Chroma memory 41, 42 Multiplication Circuits 43, 44 Low pass filter (LPF) 45 π / 2 phase shifter 46 Oscillator 47 I memory 48 Q memory 201 Luminance level adjuster 202 Chroma level adjuster 203 Hue adjuster

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H04N 5/20 H04N 5/20 11/00 11/00 11/24 (56) References JP-A-54-28521 (JP, A JP-A-47-30223 (JP, A) JP-A-3-250993 (JP, A) JP-A-3-154478 (JP, A) JP-A-61-237588 (JP, A) 33618 (JP, A) JP-A-53-112612 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H04N 9/44-9/78 H04N 5/14-5/217

Claims (5)

(57) [Claims] 1. A video equalizer that adjusts an input video signal by a luminance level adjustment unit, a hue adjustment unit, and a chroma level adjustment unit to equalize distortion, wherein the luminance signal indicates that the input video signal is a color bar signal. A color bar signal identification means for identifying from a time interval of a level change point; and a luminance level error of the color bar signal with respect to a specific color signal when the input video signal is determined to be a color bar signal by the color bar signal identification means. And a brightness level error detecting means for detecting the difference between the ratio of the I signal and the Q signal for a specific color and a specified value of the ratio, and returning the difference to the hue adjusting unit. A hue error detecting means for detecting a difference between a specified value for each of an I signal, a Q signal, or a sum of an I signal and a Q signal for a specific color, and Automatic video equalization apparatus characterized by comprising a chroma level error detecting means for feeding back to the section, the. 2. The color bar signal discriminating means determines that both an 8-color bar signal including a black signal and a 7-color bar signal are color bar signals. Item 6. The automatic image equalizer according to Item 1. 3. The luminance level error detecting means according to claim 1, wherein said luminance level error detecting means outputs a normal error even when the white signal level is both 100% and 75%. Automatic video equalizer. 4. A method according to claim 1, wherein said color bar signal discriminating means, luminance level error detecting means, hue error detecting means and chroma level error detecting means determine and detect an error from a signal of one scanning line of the input video signal. 4. The automatic video equalizer according to claim 1, wherein the automatic video equalizer is used. 5. An error signal output from said luminance level error detecting means, hue detecting means and chroma level detecting means is multiplied by A if the error value is equal to or less than a specified value (A is smaller than 1). If the above is the case, the error value is multiplied by B (B is greater than 1), added to the data value of the memory storing the correction value, and the added data value is output. 5. The automatic video equalizer according to claim 1, 2, 3, or 4.