<title>Dynamic sine wave response measurements of CRT displays using sinusoidal counterphase modulation</title>

Abstract

7 18 :013Approvd for pub5c re,•m; dietbuton uimtahd. United States Army Aeromedical Research LaboratoryFort Rucker, Alabama 36362-0577 Oualified reauestersQualified requesters may obtain copies from the Defense Technical Information Center (DTIC), Cameron Station, Alexandria, Virginia 22314. Orders will be expedited if placed through the librarian or other person designated to request documents from DTIC. Chanae of addressOrganizations receiving reports from the U.S. Army Aeromedical Research Laboratory on automatic mailing lists should confirm correct address when corresponding about laboratory reports. DispositionDestroy this document when it is no longer needed. Do not return it to the originator.The views, opinions, and/or findings contained in this report are those of the author(s) and should not be construed as an official Department of the Army position policy, or decision, unless so designated by other official dowumentation.Citation of trade names in this report does not constitute an official Department of the Army endorsement or approval of the use of such commercial items. Reviewed 23I 02 I ABSTRACT (Continue on reverse if necessay and identify by block number)The current practice of basing the performance of cathode ray tube (CRT) displays on static image quality figures-of-merit fails to provide a valid assessment of a display's ability to reproduce real-world scenes where there is relative motion within the scene or between the sensor and scene.Techniques which provide assessment of a display's capability to reproduce spatial information in a dynamic environment are needed. One technique based on response to sinusoidal counterphase modulation is presented. ABSTRACTThe current practice of basing the performance of cathode ray tube (CRT) displays solely on static image quality figures-of-merit fails to provide a valid assessment of a display's ability to reproduce real-world scenes where there is relative motion within the scene or between the sensor and scene. Techniques which provide assessment of a display's capability to reproduce spatial information in a dynamic environment are needed. One technique based on response to sinusoidal counterphase modulation is presented.

Contributive Research in Aviation Medicine, Bioengineering, Human Performance Analytic and Modeling Systems

“…But, because the rate of the beam sweep in CRTs is a constant, moving that target across frames in dynamic imagery will not greatly effect the contrast already available at a particular spatial frequency (unless the phosphor is inordinately slow as shown in Figure 4-70). This was demonstrated in a study by Verona et al (1994) using temporally modulated sine waves as generic dynamic imagery (undergoing sinusoidal counterphase modulation). They tested two CRTs, with a slow phosphor (P-1) and a fast phosphor (P-44), and found the expected spatial MTF curve, which is the reduction in contrast for higher spatial frequencies.…”

“…MIL-A-49425 (CR) states that distortion shall be no greater than 4 percent across the field-of-view. Martin et al, (1994) found distortion values less than 2 percent.…”

“…Sighting through the ANVIS should have unity gain and any deviation from this would be an estimate of magnification. Measurements taken by Martin et al, (1994) using a precision test method, found a magnification of 2 percent or less. MIL-A-49425 (CR) states that magnification shall be less than +5 percent.…”

“…Should one simply generalize previous FOMs such as the MTF for static displays, to now include data for different temporal frequencies and/or velocities of the standard stimuli, as Verona et al (1994) and Beasley et al (1995) have done for CRTs. If done for new technologies, this might produce a great deal of data, and some means of rationally reducing the data might be necessary.…”

“…Field-of-view was measured by Martin et al, (1994) and was found to be 40.4 degrees. The technique they used measured the light output of the ANVIS as a function of angular rotation.…”