Characterization of Monochrome CRT Display Systems in the Field

This article presents a review of image quality assessment methods for monochrome CRTs in the field as opposed to the laboratory. The review includes image quality programs at the University of Washington, the University of Texas at Houston, the University of Michigan, and the University of Arizona. CRT manufacturers and display-board suppliers also are concerned with image quality, particularly with respect to the life time of the CRT. The programs show that the need for image quality assessment for CRTs in the clinic is recognized. Although several experimental programs are in place, there is no universally accepted program. In fact, the clinical consequences of degraded monitor performance are not even well known and must be established. The existing programs mainly are based on the most comprehensive test pattern, the SMPTE pattern. The programs permit assessment of maximum luminance, display function, dynamic range, and contrast. They do not permit assessment of spatial resolution. There is no easy method to determine the spatial resolution in the field as precisely as desired simply because there are no visual aids (test patterns) to reliably determine loss of spatial resolution and signal-to-noise ratio using human observers. This report also presents initial and encouraging data obtained at the University of Arizona with a CCD camera. This CCD camera has the potential to be developed into an important tool for practical CRT evaluation for the clinic.