Transparency is a program which shows some basic stimuli which can be made with Reinder Verlinde’s ‘Dots & Pixels’ library for the Macintosh.
System requirements
Transparency is not a 100% normal Macintosh program and it does not properly check at startup whether its system requirements are met. Therefore, you should not run it while other programs are running or when you are not sure that the requirements it needs are met.
CPU
A 68020 or better CPU with FPU. A special PowerMac native version, called ‘Transparency PPC’ is available now.
Monitor
The main monitor (the one with the menu bar on it) must be a monitor which can be switched to both black and white and 4-colour mode.
Using the program
Start Differential. You will get several example stimuli. A mouse click leads to the next stimulus in the series. When all stimuli have been displayed a window is shown with some timing information. A mouse click quits the application.
Currently, the following stimuli are present:
• Temporal transparency
• Spatial transparency with horizontal stripes moving vertically
• Spatial transparency with vertical stripes moving horizontally
• LSNR Demo (move mouse from left to right to vary the Luminance Signal to Noise Ratio)
• Stimulus which shows correlation over a gap and contrast control (move mouse from left to right to vary contrast) The upper half of the figure contains some long-time correlations (pixels move from left to right, but are masked in the center part)
• Transparency by using 1 step every frame to the right together with N steps to the left every Nth frame (percept varies with viewing distance and retinal eccentricity)
