Image processing method for a TFT LCD

Abstract

Image compression, decompression and motion detection methods are described. Two temporally adjacent frame images, a previous time frame and a current time frame, are compressed in round-off and averaging techniques. Next, according to the compressed data of two corresponding pixels of the two frame images, whether or not the pixel of the current time frame image is of a motion picture is detected. If the pixel is of a motion picture, the compressed pixel data of the previous time frame image is decompressed, and an overdrive process is performed on the decompressed pixel data and the original pixel data of the current time frame image to produce an overdrive output. If the pixel is not of a motion picture, an overdrive process is not performed.

Description

RELATED APPLICATIONS [0001] The present application is based on, and claims priority from, Taiwan Application Serial Number 93111657, filed Apr. 26, 2004, the disclosure of which is hereby incorporated by reference herein its entirety. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to an image processing method for a display device. More particularly, the present invention relates to an image compression method, an image decompression method, and a motion picture detection method for a thin film transistor liquid crystal display device (TFT LCD). [0004] 2. Description of Related Art [0005] In the past few years, LCD devices have been widely used to replace traditional cathode-ray tube (CRT) display devices. Presently, due to the development and progress of TFT technology, using a TFT as an image pixel of an LCD has become very popular. FIG. 1 illustrates a normal process for processing an image for a TFT LCD. With reference to FIG. ...

AI Technical Summary

Benefits of technology

[0010] Therefore an objective of the present invention is to provide an image compression method and an image decompression method for a TFT LCD, to reduce the amount of image data to be stored in and retrieved from the frame memory, thereby effectively reducing the size of the frame memory and EMI level.

[0011] Another objective of the present invention is to provide a motion detection method for a TFT LCD, to ensure that the overdrive is enabled only for motion pictures, thereby avoiding noise amplification in still pictures.

[0012] Still another objective of the present invention is to provide an image compression method and an image decompression method for a TFT LCD, to simplify the operations of image compression and decompression, so as to reduce the hardware design complexity and therefore make the whole system more cost effective.

[0013] Yet another objective of the present invention is to provide a motion detection method for a TFT LCD, to improve the performance of the overdrive, and therefore the performance of image processing.

[0014] Yet another objective of the present invention is to provide an image compression method, an image decompression method and a motion detection method for a TFT LCD, to increase the quality of image display and avoid side effects of image picture degradation as generally produced by mismatches between the original image pictures and decompressed image pictures.

Problems solved by technology

However, the response time of liquid crystal molecules of an LCD for displaying motion pictures is generally slow.

However, storing all image pixels in a complete time frame requires a large frame memory buffer, particularly for a large TFT LCD panel with high resolution.

Also, the concurrent storage and retrieval of image pixels utilizing the frame memory requires a very high bandwidth bus to access the frame memory, and this makes it difficult to implement the bus interface and induces significantly high electromagnetic interference (EMI) in the TFT LCD panel.

Image compression based on DCT algorithm or vector quantization method may create some artifacts, which degrade the video pictures with artificial text or graphical patterns, and thus still require image compression with higher resolution for fine details.

Because the image source may itself be noisy or the images may be transmitted through an unreliable transmission channel easily coupled with noise, still pictures may also be treated as motion pictures, so that the overdrive intended to improve the response time for motion pictures may lead to noise amplification for still images with unpleasant visual effects.

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