JP2765272B2 - Automatic black expansion controller for luminance signal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to automatic control of a luminance signal black extension control circuit, and more particularly to an improved distribution state of a luminance signal of 50 IRE or more and a luminance signal of 50 IRE or less and a distribution state of a video signal. The present invention relates to an apparatus for automatically controlling a black extension control circuit according to an average luminance level, a white area of a video signal, a black area of a video signal, and a minimum value of a luminance signal.

[0002]

2. Description of the Related Art In recent years, there has been a remarkable increase in the size of a television screen, and as a result, demands for image quality have been increasing. In particular, the gradation of the luminance signal greatly affects the contrast of the image quality.

FIG. 3 shows a conventional black expansion control device, in which 1 is a black expansion control circuit for performing black expansion control of a luminance signal, and 2 is a black expansion control circuit that controls the control level of the black expansion control circuit 1. This circuit controls the amount of expansion correction.
Is an IC of a video chroma jungle.

In the conventional black extension control circuit configured as described above, the volume of the black extension control circuit 1 is adjusted by adjusting the volume in the black extension control circuit adjustment circuit 2 from outside. .

[0005]

However, in the above configuration, if the black expansion control amount is uniquely determined at the time of adjustment at the factory, the control amount of the black expansion control circuit is fixed at the set value. As a result, it has been impossible for the viewer to view the television with the optimal amount of black expansion correction according to the state of the video that changes gradually.

In view of the foregoing, it is an object of the present invention to provide a luminance signal automatic black expansion control apparatus that enables a viewer to view television with an optimum black expansion correction amount according to a video.

[0007]

In order to solve the above-mentioned problems, an automatic control device for a black extension control circuit of a luminance signal according to the present invention comprises: a black extension control circuit capable of black extension control of a luminance signal of a video signal; A circuit for detecting a luminance signal of 50 IRE or more of the signal, a circuit for detecting a luminance signal of 50 IRE or less, a video luminance signal distribution detecting circuit for comparing the ratio of the detected signals, and detecting an average luminance level of the video signal A
A PL detection circuit, a white area detection circuit for detecting a white area of the video signal, a black area detection circuit for detecting a black area of the video signal, a black level detection circuit for detecting a minimum value of the luminance signal,
Preprocessing means for creating a control index for evaluating the output of the video luminance signal distribution detection circuit as a fuzzy set,
Preprocessing means for creating a control index for evaluating the output of the APL detection circuit as a fuzzy set; preprocessing means for creating a control index for evaluating the output of the white area detection circuit as a fuzzy set; Preprocessing means for creating a control index for evaluating the output of the black area detection circuit as a fuzzy set; preprocessing means for creating a control index for evaluating the output of the black level detection circuit as a fuzzy set; Pre-processing means for generating a control index for evaluating the output of the video luminance signal distribution detection circuit as a fuzzy set and for generating a control index for evaluating the output of the APL detection circuit as a fuzzy set From the preprocessing means for creating a control index for evaluating the output from the CPU and the output of the white area detection circuit as a fuzzy set A control index for evaluating the output and the output of the black area detection circuit as a fuzzy set Before generating an output from the preprocessing means and a control index for evaluating the output of the black level detection circuit as a fuzzy set Fuzzy inference means for performing each fuzzy inference using an output from the processing means as input, fuzzy black expansion control output determining means for determining a fuzzy black expansion control output using the output of the fuzzy inference means, and the fuzzy black expansion control An automatic control device for a black extension control circuit of a luminance signal, comprising a black extension control amount correction circuit for controlling a control amount of the black extension control circuit in accordance with a control output of an output determining means.

[0008]

According to the present invention, a video signal of 50%
Circuit for detecting a luminance signal of IRE or more and 50IRE
An output from a video luminance signal distribution detection circuit for comparing the ratio of those signals detected from a circuit for detecting the following luminance signals, an output from an APL detection circuit for detecting an average luminance level of the video signal, and a video signal The output from the white area detection circuit that detects the white area of the image, the output from the black area detection circuit that detects the black area of the video signal, and the output from the black level detection circuit that detects the minimum value of the luminance signal are fuzzy sets. Then, a fuzzy black expansion control output is calculated by fuzzy inference, and the fuzzy black expansion control output automatically controls a black expansion control circuit for an optimal luminance signal.

[0009]

FIG. 1 shows the configuration of an automatic control device of a luminance signal black expansion control circuit according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a black extension control device for a luminance signal, and 2 denotes a circuit that controls a black extension control amount by controlling a control level of the black extension control circuit 1. FIG. 14 is a graph showing characteristics when the black extension correction is applied to the luminance signal. It is assumed that the black extension start point 1 can be changed to positions 2 and 3 by controlling the correction amount.
3 is a video chroma jungle IC, 4 is a circuit for detecting a luminance signal of 50 IRE or more of the video signal,
Reference numeral 5 denotes a circuit for detecting a luminance signal of 50 IRE or less of the video signal, and 6 denotes a distribution state of the video luminance signal by comparing the signal of 50 IRE or more detected by the circuit 4 with the signal of 50 IRE or less detected by the circuit 5. 7 is an APL detection circuit for detecting the average luminance level of the video signal, 8 is a white area detection circuit for detecting the white area of the video signal, and 9 is a black area detection circuit for the video signal. A black level detection circuit 10 for detecting the minimum value of the luminance signal; and 11, an output from the detection circuit 6 to the detection circuit 10 as an input and fuzzy inference of an optimal black expansion control amount. This is a fuzzy black expansion control device.

FIG. 2 is a detailed diagram of the fuzzy black expansion controller 11 in FIG. The fuzzy black expansion control device obtains the detection values from the detection circuits 6 to 10, and outputs the preprocessing devices 12 to 1
At 6, a control index value for evaluating a fuzzy set is created. The fuzzy inference devices 17 to 21 perform fuzzy inference using the control index values from the preprocessing devices 12 to 16 as inputs. Outputs from the fuzzy inference units 17 to 21 are supplied to a fuzzy black expansion control output determination unit 22.
Here, a fuzzy black expansion control output as an output of the fuzzy black expansion control device 11 is determined. The output from the fuzzy black expansion control device 11 is input to a black expansion control amount correction circuit 2 that corrects the black expansion correction amount of the black expansion control circuit 1. Then, the black expansion control amount correction circuit 2 controls the black expansion correction amount applied to the luminance signal of the black expansion control circuit 1 and always maintains the optimum black expansion control.

The operation of the automatic control of the luminance signal black extension control circuit configured as described above will be described below. First, the detection circuit 4 in FIG. 1 detects what percentage of one screen is 50 IRE or more,
The detected result is converted to a voltage. Next, like the detection circuit 4, the detection circuit 5 detects what percentage of one screen is 50 IRE or less, and converts the result into a voltage. The reason why similar processing is performed in the detection circuit 4 and the detection circuit 5 is to increase the detection accuracy. Next, the detection circuit 6 compares the output of the detection circuit 4 with the output of the detection circuit 5 to detect the distribution state of the video luminance signal. The detection circuit 4 and the detection circuit 5 include a black extension control circuit 1
It is preferable to set an appropriate slice level in accordance with the performance of the above. Next, the detection circuit 7 detects the average luminance level, and the result is converted into a voltage. Next, the detection circuit 8 detects a white area having a certain brightness or more and no color signal, and converts the result into a voltage. Next, the detection circuit 9 detects a black area having a brightness equal to or less than a certain value and having no color signal, and the result is converted into a voltage. In the detection circuits 8 and 9, it is preferable to set an appropriate slice level in accordance with the performance of the black extension circuit 1, as in the detection circuits 3 and 4. Next, the minimum value of the luminance signal is detected by the detection circuit 10 and the result is converted into a voltage. It goes without saying that the output of the detection circuit may be not only a voltage but also a current.

The detected values thus detected are shown in FIG.
Is input to each of the pre-processing devices 12 to 16, and a control index for evaluation as a fuzzy set in each of the pre-processing devices 12 to 16 is created. FIG. 4 shows a membership function used in the preprocessing device 12 shown in FIG. 2 for inputting an output from the circuit 6 for detecting the distribution state of the video luminance signal shown in FIG. FIG. 5 shows an input of an output from the APL detection circuit 7 for detecting the average luminance level of the video signal of FIG.
Is a membership function used in the pre-processing device 13. FIG. 6 shows a membership function used in the preprocessing device 14 shown in FIG. 2 which receives an output from the white area detection circuit 8 for detecting the white area of the video signal shown in FIG. FIG. 7 shows a membership function used in the pre-processing device 15 of FIG. 2 for inputting the output from the black area detection circuit 9 for detecting the black area of the video signal of FIG. FIG. 8 shows a membership function used in the preprocessor 16 shown in FIG. 2 which receives an output from the black level detection circuit 10 for detecting the minimum value of the luminance signal shown in FIG.

FIG. 9 is a control rule showing the relationship between the luminance signal distribution state and the black extension correction amount. FIG. 10 is a control rule showing the relationship between the average luminance level and the black extension correction amount. FIG.
Is a control rule representing the relationship between the white area of the video signal and the black extension correction amount. FIG. 12 is a control rule showing the relationship between the black area of the video signal and the black extension correction amount. FIG. 13 is a control rule showing the relationship between the minimum value of the luminance signal and the black extension correction amount.

The fuzzy inference method by the fuzzy inference devices 17 to 21 shown in FIG. 2 uses a membership function of an antecedent part, a membership function of a consequent part, and a control rule using input values which are generally performed. A fuzzy operation is performed along the line, a combined fuzzy set is calculated, the maximum value of the combined fuzzy set is used as an output combining function, and the center of gravity of the output combining function is used as an output of fuzzy inference. It goes without saying that not only the centroid method but also a height method or another output value calculation method may be used.

Fuzzy black expansion control output determining device 2 in FIG.
In step 2, the output from each of the fuzzy inference devices 17 to 21 in FIG. 2 obtained according to the above-described inference method is input, and the final black extension control correction amount is calculated by arithmetic averaging. The control of the black extension control circuit 1 is performed via the circuit 2. It goes without saying that not only the arithmetic mean but also the center of gravity method, the height method, and other calculation methods may be used.

As described above, according to this embodiment, the distribution state of the luminance signal, the average luminance level, the white area of the video signal, the black area of the video signal, or the minimum value of the luminance signal is detected. Optimal black expansion correction control according to the video state at that time can be performed.

[0017]

As described above, according to the present invention, a black extension control circuit capable of controlling black extension of a luminance signal of a video signal, a circuit for detecting a luminance signal of 50 IRE or more of a video signal, and a 50IRE are provided.
A circuit for detecting the following luminance signals, a video luminance signal distribution detection circuit for comparing the ratio of the detected signals, an APL detection circuit for detecting the average luminance level of the video signal, and a white area for the video signal A white area detecting circuit, a black area detecting circuit for detecting a black area of a video signal, a black level detecting circuit for detecting a minimum value of the video signal, and evaluating the output of the video luminance signal distribution detecting circuit as a fuzzy set. Preprocessing means for generating a control index of the above, a preprocessing means for generating a control index for evaluating an output of the APL detection circuit as a fuzzy set, and a preprocessing means for evaluating an output of the white area detection circuit as a fuzzy set Preprocessing means for creating a control index; preprocessing means for creating a control index for evaluating the output of the black area detection circuit as a fuzzy set; Preprocessing means for creating a control index for evaluating the output of the circuit as a fuzzy set; output from the preprocessing means for creating a control index for evaluating the output of the video luminance signal distribution detection circuit as a fuzzy set; The output from the preprocessing means for creating a control index for evaluating the output of the APL detection circuit as a fuzzy set and the preprocessing means for creating a control index for evaluating the output of the white area detection circuit as a fuzzy set And a control index for evaluating the output from the preprocessing means and the output of the black level detection circuit as a fuzzy set. Fuzzy inference means for performing each fuzzy inference using an output from the preprocessing means as an input; Fuzzy black expansion control output determining means for determining a fuzzy black expansion control output using the output of the logic means as an input, and controlling the control amount of the black expansion control circuit in accordance with the control output of the fuzzy black expansion control output determining means. The provision of the black expansion control amount correction circuit enables the viewer to view with optimal black expansion correction according to the video state, and the practical effect is large.

[Brief description of the drawings]

FIG. 1 is a block diagram of an automatic black extension control device for a luminance signal according to a first embodiment of the present invention;

FIG. 2 is a detailed block diagram of the arithmetic and control unit of the embodiment.

FIG. 3 is a block diagram of a conventional black extension control device.

FIG. 4 is a characteristic diagram showing a relationship (a membership function) between a distribution state of a luminance signal and a black extension correction amount.

FIG. 5 is a characteristic diagram showing a relationship (membership function) between an average luminance level and a black extension correction amount.

FIG. 6 is a characteristic diagram showing a relationship (a membership function) between a white area of a video signal and a black extension correction amount.

FIG. 7 is a characteristic diagram showing a relationship (membership function) between a black area of a video signal and a black extension correction amount.

FIG. 8 is a characteristic diagram showing a relationship (membership function) between a minimum value of a luminance signal and a black extension correction amount.

FIG. 9 is a diagram showing a control rule representing a relationship between a luminance signal distribution state and a black extension correction amount.

FIG. 10 is a diagram showing a control rule representing a relationship between an average luminance level and a black extension correction amount.

FIG. 11 is a diagram showing a control rule representing a relationship between a white area of a video signal and a black extension correction amount.

FIG. 12 is a diagram showing a control rule representing a relationship between a black area of a video signal and a black extension correction amount.

FIG. 13 is a diagram illustrating a control rule representing a relationship between a minimum value of a luminance signal and a black extension correction amount.

FIG. 14 is a graph showing characteristics when a black signal is corrected for a luminance signal.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 black extension control circuit 2 black extension correction amount control device 3 video chroma jungle 4 luminance signal detection circuit of 50 IRE or more 5 luminance signal detection circuit of 50 IRE or less 6 luminance signal distribution state detection circuit 7 APL detection circuit 8 white area detection circuit 9 black Area detection circuit 10 Black level detection circuit 11 Fuzzy black expansion controller

Claims (6)

(57) [Claims] A black extension control circuit capable of black extension control of a luminance signal of a video signal, a circuit for detecting a luminance signal of 50 IRE or more of the video signal, a circuit for detecting a luminance signal of 50 IRE or less, and the detected signals , A preprocessing means for creating a control index for evaluating the output of the video luminance signal distribution detecting circuit as a fuzzy set, and a fuzzy input using the output of the preprocessing means as an input. Fuzzy inference means for performing inference, fuzzy black expansion control output determination means for determining a fuzzy black expansion control output using an output of the fuzzy inference means as input, and the black color according to the control output of the fuzzy black expansion control output determination means. A black extension control amount correction circuit for controlling the control amount of the extension control circuit is provided, and a luminance signal of 50 IRE or more and a video signal of 50 IRE or less of the video signal are provided. Automatic black extension controller of the luminance signal, characterized by fuzzy control black extension control circuit according to the distribution state of the luminance signal. 2. A black extension control circuit for controlling black extension of a luminance signal of a video signal, an APL detection circuit for detecting an average luminance level of the video signal, and a control for evaluating an output of the APL detection circuit as a fuzzy set. Preprocessing means for creating an index; fuzzy inference means for performing fuzzy inference using the output of the preprocessing means as input; and fuzzy black expansion control output determination for determining fuzzy black expansion control output using the output of the fuzzy inference means as input. Means for controlling the amount of control of the black expansion control circuit in accordance with the control output of the fuzzy black expansion control output determining means, wherein the black expansion control amount correction circuit performs black expansion in accordance with the average luminance level of the video signal. An automatic black extension control device for a luminance signal, wherein a control circuit performs fuzzy control. 3. A black extension control circuit capable of controlling a black extension of a luminance signal of a video signal, a white area detection circuit for detecting a white area of the video signal, and an output for evaluating the output of the white area detection circuit as a fuzzy set. Preprocessing means for creating a control index;
Fuzzy inference means for performing fuzzy inference using the output of the preprocessing means as input, fuzzy black expansion control output determining means for determining fuzzy black expansion control output using the output of the fuzzy inference means, and the fuzzy black expansion control output A black extension control amount correction circuit for controlling a control amount of the black extension control circuit in accordance with a control output of the determination means, and fuzzy control of the black extension control circuit in accordance with a white area of the video signal. Automatic black expansion controller for luminance signal. 4. A black extension control circuit capable of controlling black extension of a luminance signal of a video signal, a black area detection circuit for detecting a black area of the video signal, and an output for evaluating a black area detection circuit as a fuzzy set. Preprocessing means for creating a control index;
Fuzzy inference means for performing fuzzy inference using the output of the preprocessing means as input, fuzzy black expansion control output determining means for determining fuzzy black expansion control output using the output of the fuzzy inference means, and the fuzzy black expansion control output A black extension control amount correction circuit for controlling a control amount of the black extension control circuit in accordance with a control output of the determination means; and a fuzzy control of the black extension control circuit in accordance with a black area of the video signal. Automatic black expansion controller for luminance signal. 5. A black extension control circuit capable of controlling black extension of a luminance signal of a video signal, a black level detection circuit for detecting a minimum value of the luminance signal, and an output for evaluating the output of the black level detection circuit as a fuzzy set. Preprocessing means for creating a control index; fuzzy inference means for performing fuzzy inference using the output of the preprocessing means as input; and fuzzy black expansion control output for determining fuzzy black expansion control output using the output of the fuzzy inference means as input. Determining means for controlling a control amount of the black expansion control circuit in accordance with a control output of the fuzzy black expansion control output determining means, wherein a black expansion control amount correction circuit is provided in accordance with a minimum value of the luminance signal. An automatic black extension control device for a luminance signal, wherein a control circuit performs fuzzy control. 6. A black extension control circuit capable of controlling black extension of a luminance signal of a video signal, and a 50I of the video signal according to claim 1.
3. An image luminance signal distribution detection circuit for comparing a ratio of the detected signals to a circuit for detecting a luminance signal of RE or higher, a circuit for detecting a luminance signal of 50 IRE or lower, and an average luminance of the video signal according to claim 2. An APL detection circuit for detecting a level, a white area detection circuit for detecting a white area of a video signal according to claim 3, a black area detection circuit for detecting a black area of a video signal according to claim 4, and 6. A black level detection circuit for detecting a minimum value of a luminance signal according to claim 5, a preprocessing means for creating a control index for evaluating an output of the video luminance signal distribution detection circuit as a fuzzy set, and the APL detection circuit. Preprocessing means for creating a control index for evaluating the output of the white area detection circuit as a fuzzy set, and before creating a control index for evaluating the output of the white area detection circuit as a fuzzy set. Preprocessing means for creating a control index for evaluating the output of the black area detection circuit as a fuzzy set, and before creating a control index for evaluating the output of the black level detection circuit as a fuzzy set. Processing means, and a control index for evaluating the output of the video luminance signal distribution detection circuit as a fuzzy set and an output from the preprocessing means for creating a control index for evaluating the output of the APL detection circuit as a fuzzy set. A control index for evaluating the output from the preprocessing means to be created and the output of the white area detection circuit as a fuzzy set is used to evaluate the output from the preprocessing means and the output of the black area detection circuit as a fuzzy set. The output from the pre-processing means for creating the control index and the output of the black level detection circuit are evaluated as a fuzzy set. Fuzzy inference means for performing each fuzzy inference with an output from the preprocessing means for creating a control index for determining the fuzzy black expansion control output for determining a fuzzy black expansion control output using the output of the fuzzy inference means as an input Means for controlling the amount of control of the black expansion control circuit in accordance with the control output of the fuzzy black expansion control output determination means.
A fuzzy control of a black extension control circuit according to a distribution state of a luminance signal below IRE, an average luminance level of the video signal, a white area of the video signal, a black area of the video signal, and a minimum value of the luminance signal. Automatic black expansion controller for signal.