In most radiological imaging workstations today, soft-copy diagnosis is done on a monochrome cathode ray tube (CRT) display or on a liquid crystal display (LCD). The relevance of quality control of these imaging systems has been well recognized and several methods have been used for performing quality evaluation. These methods can be broadly classified into psychophysical and analytical studies.

In this project, we developed more comprehensive comprehensive methods to evaluate the transfer function and to refine the existing techniques. Work was also done on quantifying the noise (including spatial and temporal components) on these displays and finding a relationship with results from the psychophysical studies. The ultimate aim is to devise a display system on which the image perception is not distorted due to the inherent properties of the display and effects from the human eye.

The following image shows LCD pixels magnified, in which the three components (subpixels) of each pixel and the spatial noise are clearly visible. Also shown is a typical transfer function (horizontal and vertical) for an LCD display.

Publications:

1. Amarpreet S. Chawla, Hans Roehrig, Jeffrey J. Rodriguez, and Jiahua Fan, "Determining the MTF of Medical Imaging Displays Using Edge Techniques," Journal of Digital Imaging, vol. 18, no. 4, Dec. 2005, pp. 296-310. [ PDF ]