Abstract
In an imaging system, expression of contours in image is very important. Because it influences the image quality. The contour is important in human visual system. It is significant to understand contour perception condition. In this study, stepwise density change patterns of various step and width are prepared, and subjective evaluation of the step perception of the pattern is carried out at seven kinds of observation distance and two levels of brightness. The ratio of feeling the contour or a step in each condition is obtained. From the result, as for the perception ratio it is found that step width gave big influence than the density jump. It is obtained that contour or step is not perceived if the density constant area disappears.
