JPH05137025A - Automatic video equalizing device - Google Patents

Abstract

PURPOSE:To equalize the distortions by providing such a constitution where a luminance level error detector means detects the luminance level error of a color bar signal to a specific chrome signal and feeds the level error back to a luminance level control part after the identity of the color bar signal is identified. CONSTITUTION:A CPU 10 fetches the video signals converted into the digital signals by an A/D converter 1 into a memory 2 in number equal to one line. These video signals are separated by a luminance/chroma signal separator means 3 into the luminance signals and the chroma signals. Meanwhile a color bar signal identifier means 5 decides whether the input video signals are identical with the color bar signals or not. If so, the luminance level error is detected by a luminance level error detector means 6 and outputted to a D/A converter 9-1 and then to a luminance level control part 201. An I/Q separator means 4 separates the I and Q signals from the chroma signals, and a hue error detector means 7 detects the hue error to output it to a D/A converter 9-3 and then to a hue control part 203. Then a chroma level error detector means 8 detects the chroma level error and outputs it to a control part 202 via a D/A converter 9-2.

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 distortion caused by the linear and non-linear characteristics of a transmission line of a color image signal without human intervention.

[0002]

2. Description of the Related Art A video signal of a color television or the like picked up by a television camera or the like in a remote place is transmitted to a broadcasting station having broadcasting facilities by using a microwave line. In a broadcasting station, the received color video signal is corrected after correcting the distortion caused by the linear and non-linear characteristics of the transmission line formed by the microwave line, and equalized to a normal value before being transmitted.

A conventional distortion correction method used in a broadcasting station will be described with reference to FIG. FIG. 11 is a block diagram of a conventional example. In FIG. 11, reference numeral 201 denotes a brightness level adjusting unit which adjusts the brightness level of the input video signal and outputs it. Two
Reference numeral 02 denotes a chroma level adjusting unit which adjusts and outputs the chroma level of the input video signal. A hue adjustment unit 203 adjusts the hue of the input video signal and outputs it. A waveform monitor 204 monitors the waveform of the video signal. Two
Reference numeral 05 denotes a vector scope, which displays the amplitude and phase of a subcarrier that transmits a color signal.

Before transmitting a video signal for broadcasting, a color bar signal is transmitted in order to equalize the distortion of the transmission line. 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 vectorscope 205.

Observing the brightness level on the waveform monitor 204,
If the observation result 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. As for the chroma level, the level is observed by the waveform monitor 204 or the vector scope 205. If the chroma level does not match the specified value, the chroma level adjusting unit 20
The regulator (not shown) 2 is changed to match the specified value. The hue is observed by the vector scope 205, and when it 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, in the case of transmitting an image from a remote place through a microwave line, a color bar signal is transmitted before the image is transmitted, and the distortion caused in the transmission line is manually transmitted. Was being corrected through.

For this reason, it takes a long time to perform the correction, and today, depending on a television broadcast program, a video signal transmitted from a remote place may be switched and broadcast in a unit of several minutes. The present invention, which requires a great deal of labor for correction and sometimes causes a risk of broadcasting at an incorrect level due to human error, is effective in reducing distortion caused in the transmission line from the color bar signal transmitted from a remote place. It is an object of the present invention to provide an automatic image equalizer that automatically equalizes.

[0008]

Means adopted by the present invention for solving the above-mentioned problems will be described. In a video equalizer that adjusts an input video signal with a brightness level adjusting unit, a hue adjusting unit, and a chroma level adjusting unit to equalize distortion, it is assumed that the input video signal is a color bar signal. Color bar signal identifying means for identifying from the time interval, and when the color bar signal identifying means determines that the input video signal is a color bar signal, it detects the luminance level error of the color bar signal with respect to the specific color signal, and Brightness level error detection means for returning to the brightness level adjustment unit,
Hue error detection means for detecting the difference between the ratio of the I signal for the specific color and the Q signal and the specified value of the ratio and feeding back to the hue adjusting unit, and the I signal, the Q signal, or the I signal for the specific color.
A chroma level error detecting means for detecting a difference between any one of the signal and the Q signal and a specified value for the sum and feeding back to the chroma level adjusting section is provided.

[0009]

The color bar signal identifying means examines the change point of the luminance signal level and identifies the color bar signal from the time interval of the change point. When the color bar signal identification means identifies that the input video signal is a color bar signal, the brightness level error detection means detects a brightness level error of the color bar signal with respect to the specific color signal and returns it to the brightness level adjustment section. ..

The hue error detecting means calculates the ratio between the I signal and the Q signal for a specific color, detects the difference between the specified value of the ratio between the I signal and the Q signal, and feeds it back to the hue adjusting section. Further, the chroma level error detecting means is one of the I signal, the Q signal, or the sum of the I signal and the Q signal for the specific color,
The difference between the specified value of either 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 adjusting unit.

As described above, when the input video signal is identified as the color bar signal based on the time interval of the change point of the luminance level of the input video signal and the input video signal is identified as the color bar signal, The specified value of the brightness level and the error are detected and fed back to the brightness level adjusting section, and the I signal and Q
An error from the specified value of the ratio with the signal is detected and fed back to the hue adjustment unit, and an error from the specified value of the I signal, the Q signal of the specific color, or the sum of the I signal and the Q signal is detected. Since it is detected and returned to the chroma level adjusting unit, it is possible to automatically equalize the distortion generated in the transmission line in a short time without requiring human labor.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An 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.
A concrete example of the chroma signal separating means, FIG. 4 is an operation explanatory view of a concrete example of the luminance / chroma signal separating means, FIG. 5 is an operation flowchart of the color bar signal identifying means, and FIG. 6 is an operation flowchart of the luminance level error detecting means. 7 is a specific example of the I / Q separation means, FIG. 8 is an operation flowchart of the hue error detection means, FIG. 9 is an operation flowchart of the chroma level error detection means, and FIG. 10 is an operation flowchart of the embodiment.

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

In the transmission of color images, these colors are represented by 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). (E _Q ) is transmitted by a combination of three signals. The frequency f _{SC of the} I and Q signals is 3.579.
The amplitudes of two orthogonal subcarriers of 545 MHz are amplitude-modulated by E _I and E _Q , and transmitted.

Therefore, the color bar signal E _S (t) is 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 the equation (1) is called a chroma signal.

Further, from the chroma signal of the color video signal, I
The subcarrier 2sin (2 sin (2) not amplitude-modulated between the horizontal sync signal and the white of the color bar signal is used to provide the subcarrier phase reference necessary for separating the signal and the Q signal.
πf _SC t) is inserted, which is called a color burst signal.

There are also 7 colors of color bar signals, and in this 7-color color bar signal, black disappears and 5
2.65 μs is divided into seven equal parts and each color is transmitted. Also, for the white color bar signal, E _Y = 1.
There are cases of 00 and 1.33.

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

A memory 2 stores one scanning line portion 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, 9- 1 to 3 are digital-analog converters (D / A).

As shown in FIG. 3, the luminance / chroma signal separating means 3 includes a 2-sampling delay circuit 31 and 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 two, converted into a digital signal and stored, and the 2-sampling delay circuit 31 and the adder 32 are read.
And the subtracter 33. In the 2-sampling delay circuit 31, as shown in FIG. 4B, the data read from the memory 2 is delayed by 2 sample times and input to the adder 32 and the subtractor 33.

Addition is performed by the adder 32, and 1/2 divider 34 is added.
As shown in FIG. 4C, the output divided by is the luminance signal without the chroma signal, and the luminance memory 3
6 is stored. Also, it is subtracted by the subtractor 33 and becomes 1/2
B is divided by the divider 35 to pass the subcarrier through the component
The chroma signal is separated by passing it 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 its operation to identify whether or not the input video signal is the color bar signal. .. The color bar signal identifying means 5 is executed by the CPU 10 as shown in FIG.

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

Process S104 1 is added to the count value of the counter A. Process S105 The difference between the data value read from the luminance memory this time and the previous time is obtained, and it is determined whether the difference is X or more. If YES, the process proceeds to process S106, and if NO, the process proceeds to process S103 and is repeated. ..

That is, in step S105, the change point of the color signal is detected. In the case of a color bar signal, as described with reference to FIG. 2, the luminance signal E _Y is initially sent white,
E _Y changes from 0 to 1.00 or 1.33. Next, when the color changes from white to yellow, E _Y is 1.33 or 1.00
Changes to 0.89. E _Y changes each time it changes from yellow to cyan and then from cyan to green. Therefore, for example, X is set to 0. where the change value when the color changes is the lowest.
It is set to 1/2 of 11, and the difference between the read data values is 0.
If it is larger than 55, it is determined to be a change point of the color signal.

Process S106 If the determination result of process S105 is YES, the count value of the counter A is recorded in a memory (not shown) in process S106. Process S107 1 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 proceeds to process S109, and if NO, the process proceeds to process S103 and the processes S103 to S108 are repeated. ..

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 S110
If NO, the process proceeds to step S112. That is, although the color change point of the color bar signal is checked and detected in step S105, there is a signal having a data value difference of X or more even when a general video signal is input. Therefore, in the process S109, if it is a color bar signal,
As described with reference to FIG. 2, there are eight change points that become X or more for an 8-color color bar signal and seven change points for a seven-color color bar signal. For example, it is determined that the color bar signal is not a color bar signal and the others are not color bar signals.

Process S110 Data is read from the memory in which the count value of the counter A is recorded in process S106, 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 processing S110, the time interval at the time of change is 6.5812 μs for an 8-color color bar signal,
Since there are 7.5214 μs in the case of 7 colors, if the common value of these time intervals is between 5.5 μa and 8.5 μs, it is determined to be a color bar signal. Judgment value 5.
5 to 8.5 μs is an example, and can be changed as necessary.

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 brightness 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, it is 5.5 μs, and if the difference between the data values is 122, it is 8.5 μs. 5.5 μs to 8.5 in processing S110
Whether or not it is within μs is determined by whether or not the difference between the data values recorded in the memory is within 79 to 122.

Processing S111 If the determination result of processing S110 is YES, processing S111
Then, it is determined that the signal is a color bar signal, and all processing is terminated. Processing S112 When the determination result of processing S109 and S110 is NO,
In step S112, it is determined that the signal is not a color bar signal, and all the processing ends.

Next, the operation of the brightness 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 data of white (W), yellow (YL), and magenta (MG) stored in the chroma memory 38 of the luminance / chroma signal separation means 3.

Process S202 (W-YL) / (YL-CY) = Y is calculated from the W, YL and MG data read in process S201. Process S203 It is determined whether Y calculated in process S202 is larger than 1.46, and if the determination result is YES, process S204.
If NO, the process proceeds to step S208.

That is, in step S203, the white level of the input color bar signal is _EY =, as described in FIG.
It is determined whether it is 1.33 or 1.00. E
_{If Y} = 1.33, then Y = 2.35, and if E _Y = 1.00, then Y = 0.58. If Y is larger than the intermediate value of 1.46, then white E _Y is 1.33, and small. If so, it is determined that the color bar signal is 1.00.

Processes S204 and S208 In process S204, E, which is the 100% standard value of the white level, is set.
The difference E between the value corresponding to _Y = 1.33 and W is calculated. In process S208, 75% of white level is standard value E _Y = 1.0
The difference E between the value corresponding to 0 and W is calculated.

Processing S205 and S209 In processing S205, E and E _Y calculated in processing S204 =
It is determined whether the ratio with the value corresponding to 1.33 is greater than Y%, and if the determination result is YES, the process S206.
If NO, the process proceeds to step S207.

In step S209, it is determined whether 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 is performed. 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 10, the correction value Y ₁ (Y ₁
> 1.0) to calculate E ₁ .

Processing S207 and S211 In processing S207, E calculated in processing S204, processing S2
In 11, the correction value Y ₂ (Y ₂
Multiply by <1.0) to calculate E ₂ . Process S212 In process S212, processes S206, S207, S210.
Alternatively, E ₁ or E ₂ calculated in S211 is added to the data value stored in the correction value memory (not shown).

Process S213: The correction value memory is added and stored in the process S212.
The data value to be output is output to the D / A 9-1 and the processing ends.
Whether the error E is larger than Y% in steps S205 and S209
Judge whether or not, and if it is large, E to Y₁If small, E to Y₂
The reason for multiplying by and adding to the correction value memory in step S212
If the allowable value of the error E is 2%, E is more than 2%
If it is large, quickly bring the brightness level closer to the normal level.
Correction value Y greater than 1.00₁Multiply by and E is 2
If it is less than%, and is within the tolerance, a slight error will occur.
Constant brightness rather than compensating for differences and changing brightness levels
The level is output from the brightness level adjusting unit 201.
Less than 1.00 to stabilize the output level
Y ₂I am trying to multiply.

In the embodiment, the brightness level error is detected by using the W, YL and CY level values, but the error can be detected by the same processing even if the other color levels are used. You can Next, referring to FIG.
-The Q separation means 4 will be described.

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

That is, the signal read from the chroma memory 38 is expressed as a continuous function for ease of explanation. From 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 gives the phase reference of the chroma signal, and a frequency of sin (2πf _SC t + 33 °) is oscillated and input to the multiplication circuit 41. On the other hand, the multiplication circuit 42 has an O
The oscillation output from SC46 is π / 2 with the π / 2 phase shifter.
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 in 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, the multiplication circuit 42 multiplies,
The LPF 44 removes the 4f _SC component, and the Q memory 48 stores Q = [-E _I (t) sin (α) + E _Q cos (α)] / 2 (6).

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 firstly determines the I / Q separation means 4
The data for yellow stored in the I memory 47 and Q memory 48 of

Process S302 The specified value −I / Q = E is calculated. The specified value is Equation (5)
2 and (6) are I / Q values when α = 0, and from FIG. 2, E _I for yellow is 0.32 and E _Q is −
Since it is 0.31, the specified value is -1.032. However, the I / Q receives the rotation of which the hue is α in the transmission line, and -1.
The value is different from 032.

Process S303 In process S303, E is calculated from E calculated in process S302.
Is greater than the allowable range of H degrees, and the predetermined result is Y
In the case of ES, the process S304 is performed. In the case of NO, the process S30 is performed.
Go to 5.

Whether or not it is larger than the allowable range of H degrees is determined. For example, if H is 2 degrees, α in equations (5) and (6) is determined.
By substituting 2 degrees for I / Q, when α is +2 degrees, it becomes −0.9626, E is −0.0694, and α is −
In case of 2 times, I / Q becomes -1.1071 and E becomes 0.0
It becomes 751. Therefore, E calculated in step S302
Is within the range of −0.0694 to 0.0751, the process proceeds to step S305, and if out of the range, the process proceeds to step S304.

Process S303 and S305 In process S303, E calculated in process S302 is changed to 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 step S306.

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

The reason why it is determined in step S303 whether E is greater than H degrees, and if it is large, E is multiplied by H ₁ and if it is small, H is multiplied by H ₂ to add to the data value in the correction value memory For the same reason as described in the brightness level error detection means. It should be noted that although the hue error is detected for yellow in the above-described embodiment, it 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. Process S401 In process S401, the CPU 10 first reads the data for yellow from the I memory 47 and the Q memory 48.

Process S402 In process S402, a specified value- (I + Q) = E is calculated. The chroma signal E _CH (t) is represented by the 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 E _I = 0.32 and E _Q = −0.31, as described in FIG. 2, so that V _CH = 0.446. However, it is difficult to calculate the chroma level from the equation (7), and the present invention calculates the chroma level by the method described below.

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

The data values for yellow stored in the I memory 47 and the Q memory 48 change in chroma signal level due to distortion of the transmission line, and the data values accompanied by 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 if the feedback is made so that E becomes 0, a specified chroma level can be output. it can.

Process S403 It is determined whether E calculated in process S402 is larger than C% of the allowable value. If it is large, the process proceeds to process S404, and if it is small, the process proceeds to process S405. Processing S404 and S405 In processing S404, C is added to E calculated in processing S402.
₁ (C ₁ > 1.0), and C ₂ (C 1
Multiply by ₁ <1.0) and move to process S406.

Process S406 E ₁ or E calculated in process S404 or S405
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 process S406 is output to the D / A 9-2, and the process ends.

Although the chroma level error is detected for yellow in the above-mentioned embodiment, it can be similarly applied to other colors. Further, although the chroma level error is performed on I + Q, the same chroma level error can be detected by using only the I signal or the Q signal.

Finally, the operation of the present invention will be described with reference to the flowchart of FIG. Process S501 In process S501, the CPU 10 fetches the video signal converted into a digital signal by the A / D1 for one line into the memory 2.

Process S502 The luminance / chroma signal separation means 3 described above separates the luminance signal and the chroma signal. Process S503 The color bar signal identifying means 5 described above determines whether or not the input image is a color bar signal,
If YES, the process moves to step S504, and if NO, the process moves to step S501, and steps S501 to S503 are repeated.

Process S504 The above-mentioned brightness level error detecting means 6 detects the brightness level error, outputs it to the D / A 9-1 and outputs it to the brightness level adjusting section 201. Process S505 The I / Q separation means 4 described above is used to calculate the I from the chroma signal.
Separate the signal and the Q signal.

Processing S506 The hue error detecting means 7 detects the hue error, outputs the hue error to the D / A 9-3, and outputs it to the hue adjusting unit 203. Process S507 The chroma level error detecting means 8 detects the chroma level error and outputs the chroma level error to the D / A 9-2 and the chroma level adjusting unit 202.

When the process of the process S507 is completed, the process moves to the process S501 again, and S501 to S507 are repeated.
Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and various modifications can be made according to the gist of the invention.

[0066]

As described above, according to the present invention, the following effects can be obtained. When the input video signal is identified as a color bar signal based on the time interval of the change point of the brightness level of the input video signal, and the input video signal is identified as a color bar signal, the specified value of the brightness level of the specific color and the error are detected. Detecting and feeding back to the brightness level adjusting unit, detecting an error from the specified value of the ratio of the I signal and Q signal of the specific color and feeding back to the hue adjusting unit, and I, Q signals of the specific color, Alternatively, since an error between the specified value of the sum of the I signal and the Q signal is detected and fed back to the chroma level adjusting unit, it is automatically generated in the transmission line in a short time without requiring human labor. The distortion can be equalized.

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

[Brief description of 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 the luminance / chroma signal separation means 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 the color bar signal identifying means of the embodiment.

FIG. 6 is an operation flowchart of the brightness level error detecting means of the embodiment.

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

FIG. 8 is an operation flowchart of the hue error detecting means of the embodiment.

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

FIG. 10 is an operation flowchart of the embodiment.

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

[Explanation of symbols]

 1 analog-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 Reduced 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

Claims (5)

[Claims] 1. An image equalizer that adjusts an input video signal by a brightness level adjusting unit, a hue adjusting unit, and a chroma level adjusting unit to equalize distortion, and determines that the input video signal is a color bar signal. A color bar signal identifying means for identifying from the time interval of the level change point, and a brightness level error of the color bar signal with respect to a specific color signal when the color bar signal identifying means determines that the input video signal is a color bar signal. And a brightness level error detection means for returning to the brightness level adjusting section, and a difference between a ratio of the I signal and the Q signal for a specific color and a prescribed value of the ratio is detected and returning to the hue adjusting section. The hue error detection means detects the difference between the I signal, the Q signal, or the sum of the I signal and the Q signal for a specific color, and the specified value for each, and detects the chroma level adjustment. 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 identification means determines that both the 8-color color bar signal including the black signal and the 7-color color bar signal are color bar signals. Item 1. The automatic image equalizer according to Item 1. 3. The brightness level error detecting means outputs the normal error for both the 100% and 75% white signal levels. Automatic image equalizer. 4. The color bar signal identifying means, the brightness level error detecting means, the hue error detecting means, and the chroma level error detecting means are adapted to perform determination and error detection from the signal of one scanning line of the input video signal. The automatic image equalization device according to claim 1, 2, or 3. 5. The error value output from the brightness level error detecting means, the hue detecting means and the chroma level detecting means is multiplied by A (A is smaller than 1) if the error value is equal to or less than a specified value. If so, the error value is multiplied by B (B is larger than 1) and added to the data value of the memory storing the correction value, and the added data value is output. The automatic image equalization device according to claim 1, 2, 3, or 4.