In studying videotape frame-by-frame, it is often difficult to spot subtle changes. However, by using VIS to view the frames side by side, changes can be readily identified. By scanning backward through the images, factors leading up to a problem are located. When using VIS, be sure to not only capture the images that show a problem, but also capture and study the preceding images to get a feel for the motion flow that might have set up the problem.
