Evaluation of 8 bits versus 11 bits softcopy displays

Abstract

This paper presents the outcome of an initial study to compare softcopy displays (Liquid Crystal Displays) with 8 bits contrast resolution with those of 11 bits contrast resolution. Of particular interest was decreased detection of objects and appearance of artifacts like false contours as a result of quantization. The study was based on simulation of objects like squares, discs and Gaussian nodules at different amplitudes on uniform backgrounds. We also placed simple objects like disks and Gaussian objects into a clinical image. These objects were displayed on the two different types of displays to untrained observers. These objects were also analyzed quantitatively in their digital form with a computer program made for display and analysis. The study found that subtle objects can be missed and artifacts such as false contours can occur, dependent on signal amplitude and noise. A comprehensive observer study is necessary to confirm and refine these results.