The brightness of the flash lights observed were with the threshold level or one of three suprathreshold levels. For flashes with one of three suprathreshold brightnesses, the ELI started to decrease as the intervals increased from about 10 milli-seconds irrespective of the durations. The ELI increased to a stable level at a duration of longer than about 500 milli-seconds, irrespective of the brightness. Each of the representative points has the least distortion from the other points. Further, Voronoi partition technique is used to divide the space into segregated small spaces.
Representative points represent the points in the segregated small spaces.
This report proposes a new method for improving the vector quantization so as to make an approximately equal number of points to comprise each area. One of the applications of this vector quantization method is the evaluation of illumination environment. The general evaluation of illumination value is obtained from the measured values of uniformly divided points in the space. However, this proposed method is comprised of specific measured points corresponding to the positions where human beings exist. Therefore, this evaluation is a better method for the evaluation of illuminating environments for human beings rather than more traditional uniformly spaced illumination measurement methods.