The Effects of Image Speed and Overlap on Image Recognition

Rapid Serial Visual Presentations (RSVPs) mimic the riffling of a book´s pages and are widely employed as a way of gaining familiarity with a collection of images or selecting images of interest from a collection. In a typical RSVP a number of images within a collection enter a display in (say) the lower left-hand corner and move towards the opposite corner where they disappear (´diagonal RSVP´). If the rate at which images appear on the display is high, the speed with which images traverse the display may be such that the images overlap to some degree. As a consequence there is a need to know how much overlap can be tolerated without seriously affecting image recognition. Diagonal RSVP was implemented for four different levels of overlap and four different image speeds in such a way as to separate the effects of these two parameters. Participants were required to identify theme images (such as ´ships´ or ´cars´) in a series of image sequences at various combinations of speed and overlap. In addition to recording their performance, participants also completed a questionnaire to gauge their opinion on perceived presentation speed and ease of recognition. Results showed a significant effect of both overlap and speed on the percentage of correctly identified images. On the basis of the experimental results suggestions are made concerning interaction design for RSVP.