Chain for digitization and recording of transparent images

The paper presents a system, consisting of an image analyzer, magnetic recorder, and control and processing unit, for the digitization and recording of transparent images. A fine light beam from a flying spot cathode tube illuminates the transparency at given points and a photomultiplier gathers the transmitted light. After filtering and logarithmic conversion, the signal is digitized by an analog-to-digital converter. The control and processing unit includes cabled sequencing of the addresses determining the scanning, circuits for correct scanning distortions of the image, current amplifiers feeding the deflection and focusing coils of the cathode tube, and a circuit for coding the digitized signal with one of three types of available words. Considerable attention is devoted to the analysis of the measurement errors in the digitization process and their correction.