| 摘要 |
PROBLEM TO BE SOLVED: To precisely and efficiently correct nonlinearity without requiring a special facility, in a photometer realized as a spectroluminance meter, a spectroscopic colormeter or the like. SOLUTION: An LED 24 for correction for light irradiation is provided in a light receiving sensor array 22, a computation control circuit 20 finds a correction value in each illuminance level, based on an expected sensor output level expected in the each illuminance level and an actual sensor output level, while lighting on in order at the plurality of illuminance levels with an at least known illuminance ratio, and corrects the sensor output level by the corresponding correction value in the actual measurement to serve as a measured output. The nonlinearity due to exponential-functional characteristics of a photosensor and an amplifier such as discontinuousness of input and output characteristics generated in association with switching of a gain of the amplifier for amplifying a photocurrent, and saturation of a photoelectric transfer characteristic of the photosensor is able to be corrected thereby without using large-scaled configuration such as a bench scale. COPYRIGHT: (C)2005,JPO&NCIPI
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