Abstract
Purpose: A conventional bipartite apparatus to measure color matching functions (CMFs) usually consists of plural optical paths; a path for a test stimulus consisted of three primaries, and that for the reference stimulus. The primaries should be presented to both optical paths, as "negative" light in the reference stimulus is sometimes required to complete color matching. Thus, the conventional apparatus should have plural light sources in each optical path and required complicated alignments. In order to realize a compact apparatus to measure CMFs, we developed a bipartite apparatus with time-controlled LED lights.
Method: We used a single light source, which consisted of plural LEDs inserted to a small integral sphere (4'' diameter). A beam splitter was used to divide the light into two optical paths. The optical path, which was delivered to a subject, was temporally switched alternatively. Its frequency was high enough for the observer not to detect the flicker of the lights. By changing the lighting timing of LEDs, it was possible to arbitrarily select any combinations of the LEDs to present in either the test or the reference stimulus area. Subjects adjusted the intensity of the test stimulus which was controlled by modulating the width of the driving pulse.
Results: We succeeded in building a compact apparatus that can present bipartite stimulus with a single light source by time-controlled of the LEDs. The results of the CMFs measured with this apparatus will be shown at the conference.