Description Details Author(s) References Examples
List containing stimulus parameters
with an S3 class attribute of opiTemporalStimulus
.
x
coordinate of the center of stimulus in degrees
relative to fixation
y
coordinate of the center of stimulus in degrees
relative to fixation
image
an image to display in a machine specific format
lut
if is.na(image)
then this is a lookup
table (vector) for stimulus level at each step of
rate Hz in cd/m^2. If image is
specified, then this is a list of images, in the
same format as image, that is stepped through at
rate Hz.
size
diameter of target in degrees, or scaling factor for
image if specified
color
machine specific stimulus color settings (ignored
if !is.na(image)
)
rate
frequency with which lut is processed in Hz
duration
total length of stimulus flash in milliseconds.
There is no guarantee that
duration %% length(lut)/rate == 0
.
That is, the onus is on the user to ensure the
duration is a multiple of the period of the stimuli.
responseWindow
maximum time (>= 0) in milliseconds to wait for a
response from the onset of the stimulus presentation
...
machine specific parameters
x
and y
are in degrees, with precision to one decimal place recognised.
image
is not possible on an Octopus 900.
lut
is not possible on an Octopus 900. Stimulus is at 0 dB.
rate
is in Hz, with precision to one decimal place recognised.
color
is ignored. Use opiSetBackground()
to alter stimulus color.
Not supported.
Not implemented.
Andrew Turpin <[email protected]>
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
1 2 3 4 5 6 7 8 | # A Size III flickering with a 10Hz square wave at
# location (7,7) with luminance 10 dB (HFA)
stim <- list(x=7, y=7, size=0.43, color="white",
rate=20, # one lut step per 50 ms
lut=c(0,318), # so one full lut per 100 ms == 10Hz
duration=400, # and 4 cycles per stimulus
responseWindow=1500)
class(stim) <- "opiTemporalStimulus"
|
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