Performance Evaluation for Digital Color Halftoning in Different Color Spaces

• Main Authors: Sheng-Chong Ho, 何聖崇
• Other Authors: Ching-Hsiang Tseng
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/72221041387712284587

碩士 === 國立海洋大學 === 電機工程學系 === 91 === The computer technology makes progress in a tremendous pace nowadays. Personal Computers (PCs) become more and more important in our daily work, and digital products continuously bring new technology into our life. The color inkjet printer is one of the most popular PC peripherals. Among the large variety of printing devices, only those with low prices and high quality will be favored by consumers. If we try to enhance the printing quality of the printer by improving the hardware, we often also have to increase the manufacturing cost. In this thesis, we consider enhancing the printing quality through improving the software algorithm used by the printer. Hopefully, this can be done with minimum impact on the manufacturing cost of the printer. The main objective of this thesis is to study color halftoning algorithms. Most color halftoning algorithms were designed to be used in the RGB color space. In this thesis, we consider using the CIEL*a*b* color space instead. We found that the low frequency portion of the halftone image obtained using the RGB color space performs better than that obtained using the L*a*b* color space. On the contrary, the high frequency portion of the halftone image obtained using the L*a*b* color space has better resolution than that obtained using the RGB color space. Based on the above observation, we propose a new halftoning algorithm which uses both the RGB and L*a*b* color spaces. Using a decision algorithm, we deal with the low frequency portion of the image in the RGB color space and the high frequency portion of the image in the L*a*b* color space. By doing so, we can combine the advantages algorithm with better performance the RGB and the L*a*b* color spaces to obtain as. The performance of the proposed method is evaluated subjectively and objectively by comparing the resulting color halftone images to those obtained by other methods.