著者

重松 征史

出版者

The Institute of Electrical Engineers of Japan

雑誌

電気学会論文誌A(基礎・材料・共通部門誌) (ISSN:03854205)

巻号頁・発行日

vol.110, no.4, pp.267-274, 1990-04-20 (Released:2008-07-15)

参考文献数

15

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Neural mechanism of the retina may perform the principal role of luminosity transformation. In this paper, non-linearity of the Munsell value function was discussed on the physiological basis. Amplitude response function of the retinal neurons is approximated as a sigmoidal one V=Vmax•X/(X+S). This function may more essentially express the visual process, because it could be shown that this function includes parts well fitting to the well known psychological response functions, Weber-Fechner and Steven's law.Introducing an idea of neural adaptation to this function, the Munsell value function can be more precisely approximated. The conclusive equations were expressed as V=Vmax•X/{X+S(X)} and S(X)=X0{1+5.55•X/(X+1.8•X0)}, where X0 was background light intensity or refrectance, and X was test light one. This equation means that the adaptation level S(X) varied with two components, groval intensity (X0) and local one (X).

著者

重松 征史 菅野 義之

出版者

一般社団法人 照明学会

雑誌

照明学会誌 (ISSN:00192341)

巻号頁・発行日

vol.70, no.6, pp.268-272, 1986-06-01 (Released:2011-07-19)

参考文献数

13

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A physiological intensity transform function, y=Xn/ (Xn+Sn); (sigmoidal function) was introduced by examining the stimulus-response relationship in the retinal neural-cell to lightness scale.The responses of the photoreceptor and horizontal cell show that the light intensity is transformed to be nonlinear. Their transform function is the sigmoidal one, which fits to the psychological functions at low light level of the power function and at middle level of the logarithmic one.This function also explained the characteristics of Weber's ratio as a function of light intensity by adopting the effectof light adaptation, and simulated the Munsell gray scale as well as the CIE lightness function.