European Conference on Visual Perception edition:34 location:Toulouse, France date:August 28 - September 1 2011
To study perceptual organization processes, vision scientists often use stimulus displays that consist of separated local elements, in a particular spatial arrangement and with particular element feature properties. To aid researchers in the fast and flexible generation of perceptual grouping displays we introduce GERT, the Grouping Element Rendering Toolbox for Matlab. In addition, GERT could serve as a general and transparent platform for debating, improving and unifying methods to place elements in a grouping display. GERT consists of a modular set of general functions, comprising the following steps of display generation. (1) Define the foreground structure to be perceptually evoked by the stimulus. (2) Populate this structure with foreground elements, in regular or random positions. (3) Randomly populate the rest of the display with background elements. (4) Perform an explicit statistical check to detect proximity cues, should the researcher wish to eliminate these. (5) Render the display, using a customizable element drawing function. Each individual element feature parameter is under the control of the researcher for manipulation or randomization, while the required code remains succinct. We demonstrate the creation of a variety of perceptual grouping displays, and discuss the currently implemented methods.