Introduction

Abstract

As we have often said, it is a truism that a good picture is better than a bad picture, but it has not been abundantly clear, especially to the designers of most electrooptical imaging systems, what criteria must be used to decide if the picture is good or bad. The lens designers and the airborne camera designers have done considerable research in order to know beforehand that the optics they propose to build will permit the purchaser of their equipment to resolve the specified test chart that he expects to see with their equipment. From this need to meet contractual specifications for camera and lens performance grew a sharper understanding of lens quality. Though the questions about image quality, signal, and noise in photographs are still actively argued, the effects of image quality are now sufficiently well known that one can specify hard physical parameters and expect a definite range of performance from photointerpreters using imagery produced by equipment meeting definite specifications.