A Data Acquisition and Analysis System for On-Line Calibration and Measurements of Optical Density by a Scanning Microdensitometer

Abstract

A data acquisition and analysis system has been set up for on-line measurements of spatial variation of optical density using a microdensitometer. The entire processing and control of analog and digital signals as well as data analysis and plotting is carried out using a Window 95/98 based software ‘DEPICT’ developed for the purpose. Any possible errors due to variations in the scanning motor speed, intensity of the light source, and the amplifier gain are avoided by adding a shaft encoder, a photo-detector, and an on-line calibration set up. Optical density scans with a spatial accuracy better than 25 micron over large scan lengths are obtained upto an optical density of 2.5. The data acquisition and analysis system is simple, inexpensive, and is easily adaptable to various other instruments.