
The Black Box Toolkit Page 39 of 98
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8.2.2. Tutorial 2: Rapid serial visual presentation (RSVP)
Typically RSVP involves making use of a PC as a pseudo tachistoscope where images are
presented in rapid succession with primes and masks contained in the sequence.
For a PC to successfully be able to present RSVP sequences ideally the software one is
using should be able to present a different image on each refresh or frame. For example,
at a refresh rate of 100Hz, that would mean one every 10ms. For a TFT running at a
nominal 60Hz that would theoretically be one every 16.66ms.
In this tutorial an experiment generator has been programmed to display 8 bitmapped
images in rapid succession. Each image was programmed to be displayed for 1ms. This
theoretically should mean that a new image should be displayed on each refresh.
Again all images have three 32x32 pixel blocks superimposed on to them. The left and
right blocks on the images alternated between black and white. White blocks should be
easily detectable by the opto-detectors whereas black would not.
Two opto-detectors attached to the screen of the remote PC (lines 3 and 4) were
positioned over where alternative white blocks would appear. Sensitivity should be
adjusted so that a white screen just triggers the opto-detector and illuminates the activity
LED. Alternatively if using the adjustable fixing straps the white and black blocks may be
offset slightly.
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