Biomaterial Database

A real-time method for generating random-dot motion displays of specified coherence. 1997

J Intriligator

Department of Psychology, Harvard University, Cambridge, MA 02138, USA. ji@wjh.harvard.edu

A method that allows the creation of moving random-dot patterns with any desired level of motion coherence is presented. In the present context, a random-dot pattern with 100% coherence is a sliding sheet of dots (all dots move at the same speed and in the same direction). A random-dot pattern with 0% coherence is visual dynamic noise (similar to detuned TV snow). Coherences between 100% and 0% have a specific percentage of the dots moving coherently together, while the remaining 'twinkle' in a random fashion. The use of look-up table animation allows the dot patterns to move smoothly and rapidly even on computers that lack computational speed. Additionally, the coherence of the motion in a particular region of the screen is determined by the spatial arrangement of pixel indices in that local region. Therefore, this technique allows different regions of the screen to have different levels of coherence which makes the creation of motion-defined shapes straightforward. The basics of look-up table animation are discussed and a general algorithm for creating motion with any level of coherence is presented.

UI	MeSH Term	Description	Entries
D009039	Motion Perception	The real or apparent movement of objects through the visual field.	Movement Perception,Perception, Motion,Perception, Movement
D010775	Photic Stimulation	Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.	Stimulation, Photic,Visual Stimulation,Photic Stimulations,Stimulation, Visual,Stimulations, Photic,Stimulations, Visual,Visual Stimulations
D003118	Color Perception	Mental processing of chromatic signals (COLOR VISION) from the eye by the VISUAL CORTEX where they are converted into symbolic representations. Color perception involves numerous neurons, and is influenced not only by the distribution of wavelengths from the viewed object, but also by its background color and brightness contrast at its boundary.	Color Perceptions,Perception, Color,Perceptions, Color
D003196	Computer Graphics	The process of pictorial communication, between human and computers, in which the computer input and output have the form of charts, drawings, or other appropriate pictorial representation.	Computer Graphic,Graphic, Computer,Graphics, Computer
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000465	Algorithms	A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.	Algorithm
D016248	Computer Storage Devices	Devices capable of receiving data, retaining data for an indefinite or finite period of time, and supplying data upon demand.	Mass Storage Devices,Computer Memory Systems,Computer Memory System,Computer Storage Device,Device, Computer Storage,Device, Mass Storage,Devices, Computer Storage,Devices, Mass Storage,Mass Storage Device,Memory System, Computer,Memory Systems, Computer,System, Computer Memory,Systems, Computer Memory
D016288	Computer Terminals	Input/output devices designed to receive data in an environment associated with the job to be performed, and capable of transmitting entries to, and obtaining output from, the system of which it is a part. (Computer Dictionary, 4th ed.)	Terminals, Computer,Video Display Terminals,Computer Terminal,Display Terminal, Video,Display Terminals, Video,Terminal, Computer,Terminal, Video Display,Terminals, Video Display,Video Display Terminal