밝기 척도를 위한 정신물리학 실험 방법 비교: 크기 추정법과 크기 생성법

Abstract

The psychophysical experimental methods affect the observer’s evaluation because of the bias error. Therefore, it is necessary to design experiments properly. In this study, the experimental methods were compared for the brightness scale experiment, and the effect of stimuli setting was investigated. Magnitude estimation and magnitude production were used for comparison. There were three brightness scale experiments which have different stimuli settings. Each experiment had two phases. The magnitude estimation and magnitude production were conducted in each phase. The neutral patches were used for stimuli. In magnitude estimation, observers evaluated the brightness of test stimuli by number compared with reference. Magnitude production is the inverse of magnitude estimation. Observer was provided with a number representing the magnitude of a stimulus and adjusted the luminance of the stimulus to produce corresponding brightness with given number. As an overall result, there are large differences between magnitude estimation and magnitude production. As the luminance of test stimulus increases or decreases compared to reference stimulus, the difference between results of two methods is increased. The range of test stimuli and the number of stimuli also affect the result. As the range of test stimuli became wider and the number of test stimuli increased, the effect of the experimental method decreases in a mid-range. Therefore, to reduce the bias according to the psychophysical experimental method, it is necessary to set a wide stimulus range and the number of stimuli properly when conducting a brightness scale experiment.