Abstract: Two psychophysical measurement techniques, flicker photometry and successive heterochromatic brightness matching, were used to measure changes in luminance efficiency functions with increasing levels of light adaptation. Both measurement techniques were performed using the same optical system and the same seven healthy adults as subjects. Measurements were taken at four reference stimulus intensities, 1, 10, 100 and 1000 foot-lamberts. Luminous efficiency was found to depend on both the technique and the reference stimulus intensity with which the measurements were taken. For heterochromatic brightness matching, luminous efficiency increased for longer wavelengths as reference intensity increased. Peak luminous efficiency shifted from approximately 540nm to greater than 6OOnm with increasing intensity for all seven subjects. Peak luminous efficiency was constant for flicker photometry across all intensities but the function narrowed slightly at 100 foot-lamberts.
| Limitations: |
 APPROVED FOR PUBLIC RELEASE |
| Description: |
Doctoral thesis |
| Pages: |
66 |
| Report Date: |
APR 2004 |
| Report Number: |
A843324 |
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