著者

三品 博達 田中 恒雄

出版者

社団法人 日本印刷学会

雑誌

日本印刷学会論文集 (ISSN:00400874)

巻号頁・発行日

vol.21, no.1, pp.13-21, 1983

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A New image modulation process for printing by means of laser speckle pattern is proposed and analysed theoretically by standing on optical and staitistical base. In this method, image plane laser speckle pattern is used for the modulation in a platemaking process instead of usual contact or glass screesn. It can be shown that the characteristics of image modulation in this process are closely related to the first order statistics of laser speckle which represent the intensity probability distribution function.<br>By considering the platemaking and printing process, the relation between the density of the original and printed image is obtained for various surface roughness and different parameters of optical system. As the results, the widest and most linear reproduction curve is given when the speckle pattern having the contrast value of 0.5 is used for image modulation. The screen range of speckle modulation depends strongly on the ratio of the threshold level of the sensitized plate to the average intensity level of the speckle pattern.