JPS6339280A - Picture processor - Google Patents

Abstract

PURPOSE:To make a contrast according to gradational distribution and to make picture easy to be seen by detecting the gradational distribution of the picture projected with a liquid crystal display unit with the aid of a gradational distribution detection means and correcting gamma characteristic according to the detected gradational distribution with the aid of a gamma correction means. CONSTITUTION:A processing circuit 6 reads a gamma characteristic table corresponding to the gradational distribution detected by a histogram circuit 5 from a gamma conversion table and supplies the read gamma characteristic data to the liquid crystal display unit 3. And a gamma correction means is constituted with a RAM 4 and the process circuit 6. If the gradational distribution of the picture projected with the liquid crystal display unit 3 concentrates in a medium gradation, the gamma characteristic data corresponding to the gradational distribution detected by the histogram circuit 5 is read out from the gamma characteristic table stored in the RAN 4 by the process circuit 6. And the read gamma characteristic data is supplied to the picture display unit 3. Therefore, the picture can be made easy to be seen by making the contrast.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image processing device that processes images displayed on a liquid crystal display device.

(Prior art) Fig. 2 shows a conventional example of an image processing device.
is an A/D converter that converts a video signal (analog transmission) into a digital signal. 2 is a ROM which stores data for converting the comma characteristic of the digital signal III+ in the form of a table (comma conversion table). 3 is a liquid crystal display device that displays images based on a video signal whose gamma characteristics have been converted.

[Problem that the invention seeks to solve]

Conventional image processing devices obtain constant gamma characteristics according to a table stored in ROM 2.
When the gradations of the image displayed by the liquid crystal display device 3 are concentrated in intermediate gradations, there is a problem that contrast is not obtained and the image is difficult to see.

This invention aims to make the image easier to see by adding contrast in accordance with the gradation distribution when the gradations of the image displayed by the liquid crystal display device 3 are concentrated in intermediate gradations.

[Means for solving problems]

The image processing device according to the present invention processes an image displayed on a liquid crystal display device, and detects the gradation distribution of the image displayed by the liquid crystal display device using a gradation distribution detection means. The gamma characteristics are corrected by a gamma correction means according to the gradation distribution.

[Effect]

The f-stage gamma correction in this invention corrects the gamma characteristics according to the gradation distribution of the image displayed by the liquid crystal display device. The contrast is expanded, making it easier to see.

[Actual ha example]

FIG. 1 shows an embodiment of the invention. In the figure, 1.
3 shows the same part as in FIG. 4 is RAM, which contains a table of gamma characteristics for gradation distribution (gamma conversion table)
and stored.

A histogram circuit 5 detects the gradation distribution of the image displayed by the liquid crystal display device.

Reference numeral 6 denotes a processing circuit which reads a gamma characteristic curve corresponding to the l@tonal distribution detected by the histogram circuit 5 from the gamma conversion table and supplies the read gamma characteristic data to the liquid crystal display device 3. Said I
(^M4 and the processing circuit 6 constitute a gamma correction means.

Since the image processing device of this embodiment is configured as described above, when the image projected by the liquid crystal display device is concentrated on the 1@ tone distribution or intermediate gradation, the gradation distribution detected by the histogram circuit is The corresponding gamma characteristic data is stored in RAM.
A processing circuit reads out the gamma characteristic data stored in the gamma characteristic data, and the read gamma characteristic data is supplied to the image display device. Therefore, the image has contrast and becomes easier to see.

In this embodiment, the gamma characteristic data corresponding to the detected tone distribution is read out from the gamma conversion table stored in the RAM 4, but the gamma characteristic data corresponding to the tone distribution is read out from the corresponding ROM. The same effect can be obtained even if the information is read out.

〔Effect of the invention〕

This invention has a structure that corrects gamma characteristics according to the detected gradation distribution, so even if the gradations of the projected image are concentrated in the intermediate gradations, contrast is added and the image becomes easier to see. effective.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing a conventional example of an image processing apparatus. In the figure, 3...Liquid crystal display device, 4...-RAM, 5
. . . histogram circuit, 6 . . . processing circuit. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] An image processing device that processes an image to be displayed on a liquid crystal display device includes a gradation distribution detection unit that detects a gradation distribution of an image displayed by the liquid crystal display device, and a gamma detection device that detects a gradation distribution of an image displayed by the liquid crystal display device; An image processing device comprising: gamma correction means for correcting characteristics.