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Welcome to the Active Stereogram Test

The Active Stereogram Test is a stereopsis test for stereoscopic 3D televisions with active shutter glasses. The framework of the test was written in Tscope, a C library written by Stevens et al. (see http://users.ugent.be/~masteven/tscope/)

The proposed test is based on random-dot stereograms, which are pairs of images with random visual noise. At first, the left and right image have exactly the same pattern of dots. Next, one or more objects, letters or geometrical shapes are cut out in one of the images and moved for a certain distance horizontally. When the left side of the stereogram is now directed to the right eye and the right side to the left eye, the brain tries to fuse both images into a single percept and the effect of binocular disparity is established. If a person’s stereopsis is well-developed, the cut-out objects now seem to pop out of the background of visual noise.

Applied to our test, two identical noisy images with a dimension of 1600 x 1600 pixels are pasted together. Next, one to ten little squares is cut out in one of both sides and moved 80 pixels horizontally. There were two replications for each number of squares, resulting in 20 different stereograms which are presented in random order for each participant. When displaying the stereogram full-screen (so both sides next to each other) and switching the television to 3D mode, the left and right side of the stereogram are directed to different eyes with a speed of 200 Hz and binocular disparity is established. The novelty of our test is the challenging task component: the participant has to count the number of on-screen squares (one to ten). For each image, the participant has fifteen seconds to type in the correct answer on the numeric keypad. After 20 trials, a global score is calculated and presented.At the beginning of the test, people are asked for age, gender and optical deviation. Per trial, responses, accuracies and reaction times are logged.

Please email klaas _ bombeke at hotmail dot com if you have any questions...