An Objective Method for Rating Picture Sharpness: SMT Acutance

Abstract

An objective quantity called “system modulation transfer (SMT) acutance” will generally predict or confirm a subjective evaluation of picture sharpness. The formula for calculating it is based on image magnifications and on the areas under experimental and proposed standard modulation transfer curves of each component in a photographic system. Values of SMT acutance for thirty color films and motion-picture film systems are tabulated; they range from 70 (passing) to 100 (excellent), each unit representing one just-perceptible difference in picture sharpness.