Evaluation of Direct-View Imaging Devices

Abstract

Image-intensifier devices have traditionally been evaluated by a somewhat subjective estimate of performance in terms of output picture quality, particularly limiting resolution of the output image as seen by a human observer, as a function of input image illumination. To translate these subjective impressions into quantitative data, both to spectify tube performance objectively and to identify the factors which govern performance as a guide to corrective measures, workers have agreed on several quantitative measurements of image-intensifier performance. Most important are measurements which determine the sensitivity, in terms of the brightness gain and the contrast degradation in the device due to background,* and the resolution performance of the device. Following Perrin,¹ we believe limiting resolution is completely unsatisfactory as a measure of resolution performance, and have standardized on the modulation transfer function to describe image-intensifier resolution performance.