OBJECTIVE AND SUBJECTIVE MODELING OF HUMAN COLOR PROCESSING SYSTEM AND ITS APPLICATIONS
| Autor: | Shen, Yu-Chuan, 沈毓銓 |
|---|---|
| Rok vydání: | 1997 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 85 A successful modeling of human color processing system plays animportant role for computer-based color evaluations. Conventionally, acomprehensive (both objective and subjective) color modeling from anyengineering perspective has received limited attention because of itsinvolving the complex characteristics of the physics (e.g., spectralstimuli), the physiology (e.g., color blindness), the psychophysics(e.g., color appearance), and the psychology (e.g., color imagery, colorharmony and color selection). In this study, a comprehensive colorrelationship is proposed to clarify those transforms from the input ofspectral stimuli into color appearance, color imagery, color harmony,color selection, and even color blindness.Color appearance is the color vision indicating the physiologicaladaptation to both background and viewing conditions. For a typicalphenomenon of simultaneous color contrast, the empirical "p factor"(ranged from 0 to --1) conventionally used in color appearance models isquantified by both the number of pixels and the separation betweenforeground and background colors. This quantizationreports a 0.3485% (CIE1976UCS) color-difference between the predictedand measured results. Besides, the color appearances between softcopyand hardcopy are predicted by four color models (i.e., von Kries, CIELAB, RLAB and Hunt) under the more general environments of unequalluminance levels and dim surround. Results of the Zscale values measured by the psychophysical procedure based on 30ordinary observers demonstrate that, on the average, the Hunt modelachieved the best color prediction against the worst one of the RLABmodel. Color imagery and color harmony are closely related to the psychologicalfeature of human pleasure. A new pleasure-related function of CLD(colorlinguistic distribution, corresponding to the color imagery) is proposedto quantitatively represent human mental color impression of interiorimages upon a designed one dimensional linguistic-based image scale of" EXCITING-CALM". Supported by a database, thedistribution state of CLD is capable of indicating the fashion trends inTaiwan. Also, on the image scale, the grade of color harmony can bemeasured by its CLD similarity to an RHD(reference harmonydistribution). Evaluated results demonstrate a 95.56% correlationcoefficient with those questioned from 69 young people, which is betterthan that (i.e., 50.73%) of the famous Moon-Spencer theory based on huefeature. Color selection''s performance depends chiefly on the focused feature andapplied fields. A novel technique of color selection considering colorharmony is proposed for subjective-orientedapplications. Based on encoding color image into itspleasure-related feature of CLD, the selection of colors in thetristimulus color space can correspond to the specification of CLD uponthe linguistic- based image scale. Also, the specified CLD can be decodedto tristimulus values by a reverse procedure. This design can gain 400%harmony grades over the original image. Color deficiencies inflict different color visions on almost 8.438% ofthe entire population (i.e., 6.3% for the type of "anomaloustrichromatism", 2.133% for the type of "dichromatism", and 0.005% forothers). Two potential approaches based on tristimulus values andspectrum are constructed. The tristimulus approachspecifies the related tristimulus parameters of color appearance modelto zero for representing the absence of physiological color-differencesignal to report dichromatic color-blind simulation. Also, thisspecification can be applied to the lack of physiological cone sensors(e.g., [Nature, 1995;95vienot Science, 199595david and 199696neitz]).Moreover, the spectrum approach derives the spectraltransmittance of an optic-based simulator from the reciprocal ofwavelength discrimination functions measured experimentally. In theconsideration of dichromatic population ratio, this derivation reports asimilar performance to the tristimulus approach, and is suitable to boththe dichromatic and the anomalous trichromatic color deficiencies. Finally, a concrete application of the comprehensive color relationshipis developed, called "computer-based color consultation system", forevaluating colors objectively and subjectively from the viewpoints ofcolor-normal and color-defective people. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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