視線軌跡に基づいた画像中の空間周波数特性に対する視覚探索の検討

抄録

To design novel displays guiding gaze, it is important to know how the visual search affects the perception and cognitive processing of objects. The purpose of this study was to investigate the characteristics of the visual search that are controlled by spatial frequency. We measured the detection time, accuracy rate, and scan path during eye movement in response to target stimuli. The stimuli, embedded in one of 30 areas (6 horizontal × 5 vertical directions) in background image with the broad frequency range, were presented while the spatial frequency parameter β was varied; this corresponded to the slope of the luminance power spectrum in the target stimuli. Twelve healthy men (aged 21-23 years) with normal vision participated in the experiment. The results showed a visual search threshold of 0.5 of β for both subjective and objective responses, corresponding to oral responses and support vector machine (SVM) applied to the deviation of the scan path from the target stimuli, respectively. Furthermore, the objective responses observed using SVM suggest the possibility of subconscious discrimination of target stimuli even when the subjects could not discriminate the target stimuli subjectively.