A digital test target system is described which may be used to evaluate digital imaging systems and line-scan and digital displays (soft or hard copy) in a fashion similar to the use of resolution targets for the evaluation of optical analogue image systems. The digital test target system consists of a basic pattern of checkerboards of different sizes, which is repeated with different commanded "brightness" and "contrast" levels; a procedure for reading the target; and a method of adjusting the reading scores to obtain an index of image quality. The target system presently consists of an eight-target set, arranged for evaluation of 512 pixel square matrix display having eight bit gray level capability. The system is applicable to other sized display matrices and gray level capability. An index is derived from the readings so that displays having similar image quality index values will have the same average image quality performance regardless of differences in matrix size and nominal gray level capability.