Online ISSN : 2189-552X
Print ISSN : 0389-9357
ISSN-L : 0389-9357
Volume 40 , Issue 2
Showing 1-2 articles out of 2 articles from the selected issue
Journal of the Color Science Association of Japan Vol.40, No.2
  • Hiroaki Kotera
    2016 Volume 40 Issue 2 Pages 49-59
    Published: March 01, 2016
    Released: April 25, 2016
    Atmospheric pollution by PM2.5 is exactly getting serious at China. The de-hazing or de-fogging task for polluted images has been a long-pending question at NASA remote sensing project. Currently the atmospheric scattering model is a mainstream for recovering the haze-less scene. Above all, a single image de-hazing model based on dark channel prior hypothesis by K. He et al. is most notable in practice. The key to solving this ill-posed problem lies in how to estimate the spatially smooth scene transmittance. This paper proposes an estimation method for spatially smooth scene transmittance based on atmospheric scattering model. The model introduces an anisotropic spatial filtering to reduce the banding artifact as a fatal drawback in the He’s model.The simulation shows how the proposed model enables us to look the clear scene through heavy PM 2.5 pollution or dense fog. Since any small particles are floating in the air even if under clear skies, we never see the hazeless true scenes. So far the de-hazing technologies have mainly targeted at heavy polluted scenes, but may be useful even for usual scenes. The model demonstrates how the brilliant scenic colors are restored from a slight hazy landscape by just adjusting the veiling factor for the scattered air light. Considering that we perceive aerial perspective through the air layer, the estimated scene transmittance must reflect the depth map. Lastly the paper introduces a novel application to the foreground/background separation for a perspective scene and visual effects on the spatial filtering corresponding to the each separated areas.
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  • Chanprapha Phuangsuwan, Mitsuo Ikeda
    2016 Volume 40 Issue 2 Pages 60-66
    Published: March 01, 2016
    Released: April 25, 2016
    If there is nothing placed in a space but only a uniform wall without any scratches or patterns one cannot recognize the existence of the space. If any object is inserted there he/she now can recognize the space and understands illumination filling the space although the recognition and the understanding might be slight. The object is called the initial visual information IVI. In a previous paper1) the recognition of a space started already with a little IVI of a carnation flower with a short stem but there was a gap of recognition of a space between the above IVI and no IVI. The present paper supplements the previous finding by providing observers with still smaller amount of IVI to see whether such smaller IVI gives less recognition of a space and less color constancy. It was found that with only a pair of white petals as the IVI the subject could already notice the existence of a space, understand the illumination in the space, and get the color constancy although very imperfect. The quantitative definition of IVI was proposed by the amount of whiteness which defines the degree of the color constancy.
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