A New Measure of Television Display Quality Relatable to Observer Performance
AIR FORCE AEROSPACE MEDICAL RESEARCH LAB WRIGHT-PATTERSON AFB OH
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This report describes a new, direct measurement method of determining the imaging quality of cathode-ray tube CRT, line scan displays. This measurement was specifically developed as a more critical and realistic indicator of display quality. The measurement consists of recording the modulation contrast available on the display as a function of spatial frequency. An electronic sine wave generator produces a sine wave intensity pattern of the face of a CRT display. The display luminance distribution is scanned using a telephotometer or microphotometer depending on the size of the display. The modulation contrast of the display is obtained from the photometer scan for several spatial frequencies. The resulting graph showing modulation versus frequency is defined as the Sine Wave Response SWR Curve of the display. Since human vision is not linearly related to modulation, it is desirable to transform the modulation axis to another parameter which is linearly related to vision. This can theoretically be accomplished by transforming the modulation contrast to square root of 2 incremented Gray Shades. The resulting Gray Shade Response GSR indicates how many gray shades are visible as a function of spatial frequency.
- Electrooptical and Optoelectronic Devices
- Non-Radio Communications