Microprocessor-controlled light-emitting diode dark adaptometer
Autor: | E. S. Beatrice, H. Zwick, P. A. O'Mara, D. J. Lund |
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Rok vydání: | 1982 |
Předmět: |
Physics
Optics and Photonics business.industry Computers Biomedical Engineering Absolute threshold Dark Adaptation Integrated circuit Computer Science Applications law.invention Microprocessor Data acquisition Optics Microcomputers law Psychophysics Optoelectronics Humans business Pulse-width modulation Diode Light-emitting diode |
Zdroj: | Medicalbiological engineeringcomputing. 20(1) |
ISSN: | 0140-0118 |
Popis: | A microprocessor-controlled light-emitting diode (l.e.d.) display is used to measure dark adaptation. The apparent intensity of the l.e.d. display is controlled by varying the pulse width while holding the pulse repetition rate constant. During the period of dark adaptation, the absolute threshold is measured by the method of limits. Separate series of threshold values are obtained for red and green l.e.d. stimuli. The design uses inexpensive programmable and conventional integrated circuits. Stimulus parameters, test administration, and data acquisition are under software control. The dark adaptation functions derived with this device are comparable to those obtained with other instruments. |
Databáze: | OpenAIRE |
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