電機資訊學院: 電信工程學研究所指導教授: 陳宏銘黃泰翔Huang, Tai-HsiangTai-HsiangHuang2017-03-062018-07-052017-03-062018-07-052016http://ntur.lib.ntu.edu.tw//handle/246246/276370隨著投影元件的進步，手提式的投影裝置已日漸普及。然而在日常生活中可見的投影平面卻未必是理想的白色，同時投影面的反射係數也未必理想。在本論文中，我提出了一個針對投影面的影像色彩補償系統。此系統會依照投影面的色彩及花紋在預投影的影像上做對應的修正，使得投影效果趨近於理想投影面上的結果。 人眼視覺系統的特性被大量的應用於此一色彩補償系統中。透過顏色定錨理論的應用，本系統能更精準的考慮人眼對環境色彩的適應性，進而在有色彩及花紋的投影平面上能更準確的重現一張影像原本該有的色彩。透過可見度模型的建立與使用，本系統能有效的預測哪些影像細節在非理想投影面上會變得不可見，進而對該影像細節做對應的增強。在主觀測試中，超過95%的受測者能在本系統的補償影像上看到相較於既有系統更好的色彩及影像細節。此一測試結果不僅反映了本系統的優越性，同時亦證明了視覺模型及理論可以有效的改善在非理想投影面上的投影品質。Ubiquitous projection, meaning being able to project an image anywhere, is no longer a fiction due to the miniaturization of projectors. However, flat surfaces in our living environment to be used as the replacement of a projection screen for pico or handheld projectors are not necessarily white. To improve the image quality for ubiquitous projection, a perceptual radiometric compensation system is presented in this dissertation to counteract the effect of color projection surfaces on image appearance. In the first part of the dissertation, a perceptual radiometric compensation method is presented to counteract the effect of color projection surfaces on image appearance. It reduces color clipping while preserving the hue and brightness of images based on the anchoring property of human visual system. In addition, it considers the effect of chromatic adaptation on perceptual image quality and fixes the color distortion caused by non-white projection surfaces by properly shifting the color of the image pixels toward the complementary color of the projection surface. User ratings show that the method outperforms existing methods in 974 out of 1020 subjective tests. In the second part of the dissertation, a visibility enhancement method is presented to counteract the visibility loss effect caused by the brightness scaling in the process of radiometric compensation. Based on JND theory and the HVS response model, the method effectively enhances the visibility of image details in dark regions without affecting the perceptual contrast of bright regions. The method also applies appropriate counter shading to eliminate halo effect and, meanwhile, enhance perceptual contrast of the brightness-scaled image. Experimental results are provided to show the performance of the method. In the last part of the dissertation, a simplified CIECAM02 model is presented to reduce the computational burden caused by the nonlinear color transforms of CIECAM02. Experimental results show that the simplified model reduces the computation time by 50% with only 2.3% approximation error. The speedup is important for practical applications.論文使用權限: 不同意授權針對投影幕的影像顏色補償具有相機的投影系統定錨理論人眼對顏色的自動校正CIE 色彩模型人眼視覺系統可視性模型Radiometric compensationprocamVasarely illusionchromatic adaptationCIECAM02Human visual systemvisibility modelthesis10.6342/NTU201603328