A degree of crowdedness in public pedestrian space is obtained from sequences of greyscale images and still colour images in order to provide a route selection hint to pedestrians. Two measures are employed: amount of motion and colour entropy, and they are used selectively depending on the nature of target space. The pedestrian space is categorised into two: smooth and stagnated. The smooth space urges pedestrians to flow smoothly without pausing, while the stagnated space invites pedestrians to pause for socialising. A degree of stagnation, obtained from accumulated differentiated images, is used to distinguish these two types of space. The amount of motion and the colour entropy are compared against human's sense of crowdedness for evaluation. The experiments have shown that the amount of motion represents the smooth space's crowdedness well, while the colour entropy is suitable for evaluating the stagnated space. It has also shown tendency of significance between the degree of stagnation and the types of space.

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Literatures use disparity as a principle measure evaluating discomfort, various artifacts, or movie production styles associated to stereoscopy, yet, statistics used to represent image or frame are often different. The current study examines 20 disparity statistics to find metrics that would best represent subjective stereoscopic sensation. Additionally, effect of disparity distribution pattern within an image is considered: Here, the patterns are categorised either single-peak or multiple-peak from the shape of disparity histogram. In the experiment, 14 stereoscopic images were presented to 15 subjects. Each subject evaluated perceived sense of distance and volume (3D space) through 7 points Likert scale. The result shows that the statistics that correlated significantly to the subjective sensation differed by the disparity compositions, hence, the metrics should be chosen accordingly. For the sense of distance, maximum, range, and the difference between 95th and 5th percentiles were found to be appropriate metrics under the single-peak, and minimum, contrast, and 5th percentile were representative under the multiple-peak. Similarly, for the sense of volume, range was found to be appropriate under the single-peak, but no metrics was found under the multiple-peak. The discrepancy is assumed due to different observation styles under differently composed images. We believe that the current study provides optimal disparity metrics for stereoscopic sensation measurements.

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