Motion lines

Abstract: People can keep track of target objects as they move among identical distractors using only spatiotemporal information. We investigated whether or not participants use motion information during the moment-to-moment tracking of objects by adding motion to the texture of moving objects. The texture either remained static or moved relative to the object’s direction of motion, either in the same direction, the opposite direction, or orthogonal to each object’s trajectory. Results showed that, compared to the static texture condition, tracking performance was worse when the texture moved in the opposite direction of the object and better when the texture moved in the same direction as the object. Our results support the conclusion that motion information is used during the moment-to-moment tracking of objects. Motion information may either affect a representation of position or be used to periodically predict the future location of targets.

Abstract: Still images can portray motion by using a stylized technique. Most of these techniques are commonly used for dynamic images as well (e.g., for cartoons). Typically, an artist abstracts the motion of a specific scene or animation to illustrate movement. Depicting motion in real-time environments is no less essential, and therefore a similar approach is desirable. Our approach is focused on three methods to stylize motion: squash-and-stretch, multiple images, and motion lines. A discussion of these methods for depicting motion in dynamic images and an implementation are presented in this paper. Finally, we discuss the results and conclude with the outlook for further development.

Abstract: We present an experimental study exploring how to best guide users when playing RealDance, a next generation dancing game prototype. It uses four Nintendo Wii remotes, attached to the wrists and ankles, to create a 3D spatial interface utilizing the entire body to more closely mimic real dancing. Since RealDance requires a player to use both arms and legs, the player needs to know which of their four limbs to use, where they are expected to move, and when they are expected to move in the dance sequence. To understand the best way to present this information, we implemented three visual interface methods: Timeline, Motion Lines, and Beat Circles, that are based on existing rhythm video games but extended to support RealDance's 3D interaction requirements.Our study explores each visual interface's effectiveness in conveying dance sequence information and assisting the player in providing a rewarding experience. Our evaluation is based on points scored in the game, and post-questionnaires used to solicit reactions about each visual interface including which was preferred and why. The results of the study show that players had significantly higher scores when using Motion Lines and Beat Circles than with the Timeline. The results also indicate that players found Motion Lines and Beat Circles significantly easier to follow than Timeline and icon position significantly less confusing than the Timeline interface. From these results, we believe that Motion Lines and Beat Circles are more appropriate visual interfaces than the traditional Timeline interface for full body, rhythm dance games.

Abstract: How do spatially disjoint and ambiguous local motion signals in multiple directions generate coherent and unambiguous representations of object motion? Various motion percepts, starting with those of Duncker (Induced motion, 1929/1938) and Johansson (Configurations in event perception, 1950), obey a rule of vector decomposition, in which global motion appears to be subtracted from the true motion path of localized stimulus components, so that objects and their parts are seen as moving relative to a common reference frame. A neural model predicts how vector decomposition results from multiple-scale and multiple-depth interactions within and between the form- and motion-processing streams in V1–V2 and V1–MST, which include form grouping, form-to-motion capture, figure–ground separation, and object motion capture mechanisms. Particular advantages of the model are that these mechanisms solve the aperture problem, group spatially disjoint moving objects via illusory contours, capture object motion direction signals on real and illusory contours, and use interdepth directional inhibition to cause a vector decomposition, whereby the motion directions of a moving frame at a nearer depth suppress those directions at a farther depth, and thereby cause a peak shift in the perceived directions of object parts moving with respect to the frame.