OPI (version 1.6)

opiKineticStimulus: Stimulus parameter list.

Description

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

Details

The list should contain the following elements.

• pathlist of (x,y) coordinates in degrees that is usable byxy.coords()
• imageimage[i]is the image to display (in a machine specific format) in the section of the path specified bypath[i]..path[i+1].
• levelsifis.na(image)thenlevels[i]is the stimulus level in cd/$\mbox{m}^2$in the section of the path specified bypath[i]..path[i+1]
• sizessizes[i]is the size of stimulus (diameter in degrees) to use for the section of path specified bypath[i]..path[i+1], or a scaling factor forimages[i].
• colorscolors[i]is the color to use for the stimulus in the section of path specified bypath[i]..path[i+1]. Ignored if !is.na(image).
• speedsspeeds[i]is the speed (degrees per second) for the stimulus to traverse the path specified bypath[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/$\mbox{m}^2$, 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 round to the nearest Goldmann Size I..V for display. }

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

# 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"