Physical color measurements of gold object can only indicate that the color is yellow. We have already proposed a hypothesis that recognition of gold color requires recognition of shape of the object as a necessary step before the recognition of gold color. We now focus on an image reflection of ambient environment on a surface of an object. We consider that the image reflection assists us to recognize the shape of the object correctly. We thus consider image reflection consequently assists us to recognize gold color. We have taken photographs of gold plated spoon in two different lighting conditions and have gotten two different appearances of pictures with and without the surface reflection of the ambient objects. Subjective evaluation of the two pictures has shown that gold color recognition was rather difficult on the picture with no surface reflection of ambient objects. The subjective evaluation has also shown that shape recognition of the object was difficult on the picture with no surface reflection of ambient objects. We thus conclude that the surface reflection of ambient objects assists us to recognize the shape of the object and consequently assists us to recognize gold color.

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Recently, resolutions of printing devices are increased rapidly. Obviously, higher resolution makes better quality for any type of print. In regard thermal printing technology, highest resolution of mass production printhead is 600dpi except for the particular application of higher resolution than 600dpi with small quantity.
To search the possibility of much higher resolution by thermal printing method, Kyocera developed 2400dpi and 4800dpi thermal printhead, and made printouts successfully. Printouts by those ultra high resolution thermal printhead are too small to see by naked eyes. Microscope is required to see it. The other hand, there are issues to solve as thermal printing with this ultra high resolution. In this paper, future possibility and issues of ultra high resolution thermal printing are introduced. Also the new potential application will be discussed.

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Positively or negatively charged electrophoretic white particles were prepared via two step chemical reactions : 1) modification of TiO₂ particles with silane coupling agents having polymerizable moiety or quaternary ammonium moiety, and 2) graft polymerization of hydrophilic monomer in the presence of modified TiO₂ particles. Characteristics of electrophoretic image display containing these particles were highly influenced by addition of non-ionic surfactants. Some surfactants in sorbitan derivatives with large HLB number were very effective to improve display characteristics, and increase electrical conductivity of Isopar G solutions. These non-ionic surfactants might promote dissociation of ion pairs, and therefore accelerate electrophoretic mobility of TiO₂ particles dispersed in Isopar G.

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Usefulness of near infrared image acquired by commercial digital cameras is undisputable in remote sensing analysis for vegetation estimates and detection of faded black strokes on archeological wooden materials. It has not been so clear that what region of chromaticity space near infrared light signal would be reproduced in images of visible light. Is it possible for infrared images of foliage to be used to estimate vegetation activity of plant in captured images without using a high-cost and professional spectral radio-photometer? The main purpose of this research is to clarify the characteristics of infrared images by the digital camera and to utilize its special features for a lower-cost detection of vegetation activity from the infrared images. It was manifested that an artificial sunlight lamp shows several peaks in infrared spectral region and its reflection could be detected in the infrared images by digital cameras. The detection and estimation of foliage activity seems to be feasible to generate NDVI (Normal Difference Vegetation Index) distribution from near infrared image and visible red image acquired by the digital camera.
Results from the NDVI distribution map show high correlation with the NDVI derived by measured spectral reflectance of green foliage.

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The traditional theories of scene recognition, scene gist, change detection and blindness have emphasized the role of achromatic (luminance) information in high-level vision. However, the accumulating behavioral, neuroimaging and psychological evidence indicates that the surface color of an object and the coloration of a scene affect their cognition. In this article, we discuss the research that examines the conditions under which color influences the operations of high-level vision and the neural substrates that might mediate these operations. Also individual difference of color perception and recognition might be attributed to the plasticity of high-level vision. The relationship between color and cognition must be emphasized in the model of high-level vision.

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Recently, with the development of CCD or CMOS imaging sensor, and imaging system, multi-spectral imaging is expected to be the key imaging technology to measure the spectral information on the tissue. In this manuscript, the multi-spectral imaging techniques are introduced from its basis to application. The skin image analysis and endoscopic image processing are specially introduced on this manuscript.

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This paper introduces several interesting topics on color perception. The topics are as follows : How our visual system should be factorized? Can we really distinguish between reflective objects and emissive objects? Do emissive displays really fatiguing than reflective displays? Can color appearance of emissive displays be really constant when lighting condition is varied? What is gold color? How is the importance of color for human? Several results of simple experiments related with these topics are introduced and discussed. These experimental results do not always agree with our simple prejudices. We hope such disagreements remind us that color is really interesting, full of pitfalls, and worthy of intensive regard.

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The CIE color appearance model (CIECAM02) is reviewed in related to the human visual information processing. Then, the CIECAM02-UCS giving a uniform color space for color difference formula is introduced as an application of the CIECAM02.

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Structural colors are widely distributed in the natural world and have attracted considerable attention as nanostructures anticipating a coming photonic era. The fundamental optical processes contributing to the structural colors are described in relation to their coloration mechanisms, which include thin-film and multilayer interference, photonic crystal, diffraction grating and light scattering. Finally, the principles of structural colorations in the natural world and the importance of multi-functionality found in the biological system are emphasized.

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Colloidal liquid of gold or silver nanoparticle exhibits red or yellow color, respectively, as well as the film containing them. This is because the surface plasmon in the nanoparticle co-oscillates in accordance with the incident light of a certain wave length, and absorbs the light. As a result, the complementary color of the absorbed light is observed. In this article, the mechanism of the light absorption by surface plasmon is briefly explained together with the factors which influence the wave length of the absorbed light. Next, the preparing method of gold and silver nanoparticles developed by the authors is shown. Finally, an example of application, where the gold nanoparticle was used as a coating colorant, and the characteristics of the plasmon coloring are exhibited.

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