Stimulus parameter list.

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Description

List containing stimulus parameters with an S3 class attribute of opiKineticStimulus.

Details

The list should contain the following elements.

  • path list of (x,y) coordinates in degrees that is usable by xy.coords()

  • image image[i] is the image to display (in a machine specific format) in the section of the path specified by path[i]..path[i+1].

  • levels if is.na(image) then levels[i] is the stimulus level in cd/m^2 in the section of the path specified by path[i]..path[i+1]

  • sizes sizes[i] is the size of stimulus (diameter in degrees) to use for the section of path specified by path[i]..path[i+1], or a scaling factor for images[i].

  • colors colors[i] is the color to use for the stimulus in the section of path specified by path[i]..path[i+1]. Ignored if !is.na(image).

  • speeds speeds[i] is the speed (degrees per second) for the stimulus to traverse the path specified by path[i]..path[i+1].

  • ... machine specific parameters

Octopus 900

x and y are in degrees, with precision to three decimal places recognised.

image is not possible on an Octopus 900.

levels are in cd/m^2, and are rounded to the nearest one tenth of a dB for display.

colors are ignored. Use opiSetBackground() to alter stimulus color.

sizes are in degrees, but are rounded to the nearest Goldmann Size I..V for display.

Kowa AP 7000

Only a simple path with a start and an end point is supported by the AP-7000.

x and y are in degrees and should only be length 2. (precision?)

image is not possible on an Kowa AP 7000.

levels are in cd/m^2 in the range 0.03 to 3183, and are rounded to the nearest one tenth of a dB for display. (precision?)

colors one of .KowaAP7000Env$COLOR_WHITE, .KowaAP7000Env$COLOR_GREEN, .KowaAP7000Env$COLOR_BLUE, and .KowaAP7000Env$COLOR_RED.

sizes are in degrees, but are rounded to the nearest Goldmann Size I..V for display.

speeds are in degrees per second in the range 3 to 5.

Author(s)

Andrew Turpin <aturpin@unimelb.edu.au>

References

Please cite: A. Turpin, P.H. Artes and A.M. McKendrick "The Open Perimetry Interface: An enabling tool for clinical visual psychophysics", Journal of Vision 12(11) 2012.

http://perimetry.org/OPI

Examples

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    # A Size III white kinetic stimuli on
    # a bilinear path {(27,27), (15,20), (0,0)} 
stim <- list(path=list(x=c(27,15,0), y=c(27,20,0)),
                sizes=rep(0.43,2), 
                colors=rep("white",2), 
                levels=rep(318,2), 
                speeds=c(4,3))
class(stim) <- "opiKineticStimulus"