階調数伸長処理による画質向上法 [in Japanese] Bit-Length Expansion for Digital Images [in Japanese]
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Bit-length of digital images is decided by the Analog to Digital (AD) converter. The bit-length expansion technique is necessary for the high-quality display such as the liquid crystal display (LCD) and the plasma display. Moreover, bit-length expansion is also necessary for low-bit length images, which are degraded by the pseudo-contour. In this paper, we propose a bit-length expansion method from M-level to N-level (<i>N</i> = 3(<i>M</i> -1)+1). This operation means that two quantization-levels are introduced between existing levels. The bit-length expansion method results in the estimation problem of an error image between an M-level's image and an N-level's image. The error image is the pattern image which is consisted of three values. We show the estimation method of the three values pattern image and the proposed method can remove the pseudo-contour of digital images through a lot of application results.
- IEEJ Transactions on Electronics, Information and Systems
IEEJ Transactions on Electronics, Information and Systems 128(3), 484-492, 2008-03-01
The Institute of Electrical Engineers of Japan