JPH05122550A - Signal processor - Google Patents

Abstract

PURPOSE:To obtain the signal processor which eliminates the sense of visual incompatibility in case of switching a conversion table. CONSTITUTION:An output video signal 105 is obtained by converting an input video signal 101 in a conversion table group 104. For the discontinuity of signals generated in case of switching a basic conversion table 102, an interpolation conversion table 103 is selected in the middle of switching the basic conversion table 102. Thus, the discontinuity between fields in the case of a signal processing can be suppressed less than detection limit, and the signal processing eliminating the sense of visual incompatibility is enabled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal processing device for processing a signal such as a video signal.

[0002]

2. Description of the Related Art In recent years, digital signals have been digitally processed with the increase in the speed of logic devices and arithmetic units and the increase in memory capacity.
In particular, real-time processing has become easier, and complicated video signal processing has been introduced into video-related equipment and commercialized.

In order to improve the display characteristics of a liquid crystal display or the like by digital video signal processing, the processing method must be flexibly changed depending on the characteristics of the display element, and the high-speed video signal accompanying the higher resolution of the display. Often requires processing. In that case, a method of preparing a plurality of conversion tables and switching them is used.

An example of the above-mentioned conventional signal processing apparatus will be described below with reference to the drawings. FIG. 3 is a block diagram of a conventional video signal processing device.
In FIG. 3, 301 is an 8-bit input video signal, 3
Reference numeral 02 denotes a conversion table of input 8 bits and output 10 bits, in which optimum conversion characteristics are written in consideration of all optical characteristics including the liquid crystal display to be used. 303 is a conversion table group, 304 is a 10-bit output video signal, 30
Reference numeral 5 is a feature extraction conversion control unit, and 306 is a conversion table switching control signal.

The operation of the video signal processing device configured as described above will be described below with reference to FIGS. 3 and 4.

The input video signal 301 input in (FIG. 3)
Is converted by one of the conversion tables of the conversion table group 303 that obtains the optimum conversion characteristic, and the output video signal 304 is converted.
Becomes

The feature extraction conversion control unit 305 calculates APL, black peak, white peak, and luminance distribution data for one field period from the input video signal 301, and patterns the pattern to calculate an optimum conversion table number by pattern matching. Then, the conversion table number is output as the conversion table switching control signal 306, and the optimum conversion table in the conversion table group 303 is selected.

Next, a detailed description will be given. Conversion table group 3
03 are classified as shown in FIG. In FIG. 4, the conversion tables whose physical distances are close are arranged so that their conversion characteristics are also close. Now, assume that the conversion table 0 is selected as the conversion table. If the optimum conversion table is the conversion table 1 for the input video signal of the next field and the optimum conversion table is the conversion table 18 for the input video signal of the next field, the conversion table 1 and then the conversion table 18 are selected. .. In this way, the optimum conversion table for each field is selected.

[0009]

However, in the above configuration, when the change in the image in the adjacent field is small, different conversion tables are selected even though the original images are almost the same visually. Since different conversions are sometimes performed, there is a problem in that the converted images become images that are greatly different in the adjacent fields and that a visual discomfort is felt.

In view of the above problems, the present invention provides a signal processing device which does not cause a sense of discomfort due to switching of conversion tables even if the conversion tables are switched field by field.

[0011]

In order to solve the above problems, the signal processing apparatus of the present invention selects a plurality of basic conversion tables that are switched depending on the characteristics of digital signal data and a transition period during the switching of the basic conversion tables. And a switching control unit that controls switching between the basic conversion table and the interpolation conversion table.

[0012]

According to the present invention, with the above-described structure, conversion tables that interpolate the conversion tables are selected during the transition transition period of the conversion tables, and signal processing that does not cause visual discomfort even when the change in the image of the adjacent field is small. It will be possible.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A signal processing apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

In this embodiment, the case where the device of the present invention is used as a video signal processing circuit of a liquid crystal display will be described. FIG. 1 is a block diagram of a video signal processing device according to an embodiment of the present invention. In FIG. 1, 101 is an 8-bit input video signal, 102 is an input 8-bit, output 10-bit conversion table, and the optimum conversion characteristic is written in consideration of all optical characteristics including the liquid crystal display to be used. Therefore, in this specification, it is referred to as a basic conversion table. Reference numeral 103 denotes a conversion table of input 8 bits and output 10 bits, which is a conversion table for interpolating characteristics between the basic conversion tables 102 calculated by the basic conversion table 102, and is referred to as an interpolation conversion table in this specification. 104 is a conversion table group composed of the basic conversion table 102 and the interpolation conversion table 103,
Reference numeral 105 is a 10-bit output video signal, 106 is a feature extraction conversion control unit, and 107 is a conversion table switching control signal.

The operation of the video signal processing device configured as described above will be described below with reference to (FIG. 1) and (FIG. 2).

In FIG. 1, the input video signal 1
01 is a conversion table group 104 (basic conversion table 102
Alternatively, one of the interpolation conversion tables 103) that provides the optimum conversion characteristics is converted into the output video signal 105.

For this conversion, one conversion table that provides the optimum conversion characteristic is selected from the conversion table group 104.
Optimal conversion characteristics are written in each conversion table in consideration of all optical characteristics including the liquid crystal display used.

The feature extraction conversion control unit 106 calculates APL, black peak, white peak, and luminance distribution data for one field period from the input video signal 101 to form a pattern, and calculates the optimum basic conversion table number by pattern matching. Next, the difference value between the image data of one field before stored in the field memory and the image data of the current field is calculated. If the difference value is larger than the threshold value, the scene has changed and the basic conversion table number calculated previously Is output as the conversion table switching control signal 107. When the difference value of the image data is smaller than the threshold value, there is not much change in the scene. At this time, if a basic conversion table different from that in the previous field is selected, visual flicker or the like may occur. Therefore, at this time, the interpolation conversion table 103 is selected to prevent a sense of incongruity such as visual flicker. The optimum conversion table number is the conversion table switching control signal 10
7, and the optimum conversion table in the conversion table 104 is selected.

Next, a detailed description will be given. Conversion table group 1
04 are classified as (FIG. 2). In FIG. 2, the conversion tables whose physical distances are close are arranged so that the conversion characteristics are also close. Now, it is assumed that the basic conversion table 0 201 is selected as the conversion table. When the difference value between the image data of one field before and the image data of the current field is larger than the threshold value, the scene changes, and the basic conversion table is selected. For example, the optimum conversion table is calculated as the basic conversion table 1. Then, the basic conversion table 1202 is selected. As described above, when the difference value between the image data of one field before and the image data of the current field is larger than the threshold value, the basic conversion table is selected. However, when the difference value between the image data of one field before and the image data of the current field is smaller than the threshold value, there is not much change in the scene, and the basic conversion table to be selected next is the basic conversion table 1202. However, it does not move immediately. Interpolation conversion table 0 205, interpolation conversion table 1 20
6. After the interpolation conversion table 2 207 and the interpolation conversion table are selected, the basic conversion table 1 202 is selected.

As described above, in this embodiment, a plurality of basic conversion tables that are switched according to the characteristics of the digital signal data, the interpolation conversion table selected during the transition period of the basic conversion table switching, the basic conversion table, and the interpolation conversion table. By providing the switching control unit for controlling the switching, the visual flicker or the like is not generated even when the conversion table is switched.

The present invention is not limited to the above-mentioned embodiment, and the characteristics extracted from the display image, the physical specifications of the conversion table, the switching timing of the conversion table are not limited, and the apparatus using the present invention is not limited. Is not limited to liquid crystal displays.

[0022]

As described above, according to the present invention, a plurality of basic conversion tables switched according to the characteristics of digital signal data, an interpolation conversion table selected in the transition period of the basic conversion table switching, the basic conversion table, and the interpolation. By providing the switching control unit that controls the switching of the conversion table, it is possible to combine the flexibility of changing the processing contents only by rewriting the conversion table and the high-speed adaptive processing capacity according to the display image. There is no visual discomfort even in time. Therefore, it is possible to cope with a change in signal processing corresponding to a change in various optical characteristics of the display element, and further, real-time processing of a moving image becomes possible.

[Brief description of drawings]

FIG. 1 is a block diagram of a signal processing device according to an embodiment of the present invention.

FIG. 2 is an arrangement diagram of a conversion table group of the signal processing device of the present invention.

FIG. 3 is a block diagram of a conventional signal processing device.

FIG. 4 is an arrangement diagram of a conversion table group of a conventional signal processing device.

[Explanation of symbols]

 101 Input Video Signal 102 Basic Conversion Table 103 Interpolation Conversion Table 104 Conversion Table Group 105 Output Video Signal 106 Feature Extraction Conversion Control Unit 107 Conversion Table Switching Signal

Claims (10)

[Claims] 1. A signal processing device for converting digital signal data according to a table, wherein a plurality of basic conversion tables are switched depending on characteristics of the digital signal data, and an interpolation selected during a transition period of switching the basic conversion table. A conversion table and a switching control unit that controls switching between the basic conversion table and the interpolation conversion table are provided, and an output of the switching control unit is connected to an input of the basic conversion table and an input of the interpolation conversion table. A signal processing device characterized by the above. 2. The signal processing apparatus according to claim 1, wherein the basic conversion table is obtained by calculation from digital signal data. 3. The basic conversion table does not change its contents during processing of digital signal data.
The signal processing device described. 4. The signal processing apparatus according to claim 1, wherein the interpolation conversion table is obtained by calculation from the basic conversion table. 5. The interpolation conversion table does not change its contents during processing of digital signal data.
The signal processing device described. 6. The signal processing apparatus according to claim 1, wherein switching between the basic conversion table and the interpolation conversion table is performed in units of one field period. 7. The interpolation conversion table is selected after the basic conversion table is selected.
The signal processing device described. 8. The signal processing device according to claim 1, wherein the digital signal data is a video signal. 9. The signal processing apparatus according to claim 1, wherein the basic conversion table and the interpolation conversion table are constituted by a digital memory. 10. The signal processing device according to claim 1, wherein a processor is used as the switching control unit.