Display technology for radiology

Objectives

A brief overview on the operating principles of current display technologies, namely catho-de-ray-tube (CRT) monitors and active-matrix liquid crystal displays (AMLCD), will be given. Physical properties having major impact on the perceived image quality, and respective measurement procedures will be described. Based on this introduction, the results of the evaluation of several displays will be discussed.

Materials and methods

The luminance output of displays, veiling glare, and reflected ambient light were measured with a high precision photometer by LMT (L1003). Resolution measurements were performed with a scientific CCD camera system. The images of the CCD camera were object to various calibration procedures and feature extraction algorithms developed at Aachen.

Results

The highest overall image quality is provided by monochrome CRT displays. However, the latest generation of LCDs is almost similar in terms of resolution. Yet, the LCD technology suffers from severe drawbacks in the gray-scale rendition.

Conclusion

Although LCD technology is developing very rapidly, it has not yet achieved the quality to replace standard displays based on CRTs. Standard computer monitors show least quality and require sophisticated image processing to be employed in medical imaging.