Characterization of distribution pattern of eye fixation pauses in observation of knotty wood panel images

Wood is widely accepted as a human-friendly material. Many people use a large amount of wood in their living space. However, information on why and how humans are affected by wood is insubstantial. Understanding what a person is focusing on when looking at wood is an important first step in solving the above problem. The manner and style of our wood observation can be extracted directly by using an eye-tracker. The purpose of this study is to characterize the distribution pattern of eye fixation pauses in observing wood including many knots. Fifty-five kinds of wood panel images were prepared as visual stimuli. Various sizes of knots appeared on most of them. Twenty subjects observed these images for about 20 seconds per image freely with the eye-tracker on their heads. Their eye movements were recorded as eyemarks during the observations, and many eye fixation pauses on each image were extracted for each subject. To express the distribution pattern of the eye fixation pauses quantitatively, two numerical indexes, the aspect ratio and the rate of expansion, were proposed in this study. The former index indicated the overall shape of the distribution, and the latter corresponded to the size of the observation area. Based on the relationships between these indexes, the distribution patterns were classified into three types.