The Journal of The Institute of Image Information and Television Engineers

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Digital drive systems for TFT-LCDs generally require multi gray-scale voltage sources. This paper proposes a multi-gray-scale drive method with binary values using an alternating voltage drive method : in place of gray-scale voltage sources, gray-scale signals that are digital signals are input to the drivers. A gray-scale signal is the signal that has a duty ratio whose average value is equal to the gray-scale voltage in the conventional drive system. A drive composes waveforms whose average values correspond to the data by combining the gray-scale signals and outputs them via output buffers. As the gray-scale signals can be generated by the same ASIC generating control signals, the circuitry of the drive system can be greatly simplified. We have developed a 4-bit drive system by using this method and have applied it to mass-produced modules. We have also developed a prototype 6-bit drive system and have showed that this method is applicable to generating 64 gray scales.

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Recent years have seen composite coding systems based on intraframe coding and component MC (motion compensation) coding systems utilizing MPEG-2 with a Y/C separation. But because these conventional systems have drawbacks such as low coding efficiency and quality degradation, respectively, we have developed the motion-compensated NTSC composite coding system “MUCCSII”. Significant coding gain is obtained by the mixed mode coding, and significant quality improvement is obtained by the quantization cube. Results of subjective and objective assessment tests prove that quality degradation of the system is less than 12% at 12-18 Mbps and that the system outperforms intraframe composite coding systems and MPEG-2 component coding systems with Y/C separation.

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A visualization method of multiple images by one monochromatic image is presented on the basis of the projection pursuit approach of the inverse process of the anisotropic diffusion which is a method of image restoration preserving intensity edges. The proposed method is derived through successive improvements added onto the principal component analysis, which is one of the most basic projection pursuit schemes. The annealing technique is incorporated into the optimization process of the present method and its convergence properties are analyzed. An application of this method to an example of MRI images of a brain reveals its promising performance.

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