出版社：The Society of Photographic Science and Technolgy of Japan
摘要：Recently, we have made a high-speed simple-operating RMS granularity measuring instrument which could be used with microdensitometer connected directly with it.We call it a “one-touch” RMS granularity measuring instrument.This instrument has so fast scanning speed on a sample that it needs very short computing time in analog computing circuit and consequently instantaneous RMS granularity measurement can be attained.This instrument also has a simple operating mechanism and one can obtain directly digitallyrepresented RMS granularity values at only 2-3 sec after one has pushed the starting button.The researches on circularly scanning RMS granularity measuring instrument were already reported by several authers but in any measuring instrument, the out-put signals of microdensitometer were connected to RMS voltmeter directly and were read by eyes.In our method, however, this RMS granularity measuring instrument have analog computing circuits internally so the improvement of measuring accuracy and digitalization of signals can be attained easily.Moreover, vibrational noise from rotating mechanism is far less than computing ciscuit noise (RMS; 0.003).The error of this instrument is about 4%.From result of our RMS granularity measurement for two kinds of photographic film it was ascertained that the aperture-independent Selwyn's granularity relation was fairly well hold, and good coincidence with other instruments was also obtained.
