A class for presenting grating stimuli
Categories: Stimuli Works in: PsychoPy
Name of this component (alphanumeric or _, no spaces)
How do you want to define your start point?
Options: - time (s) - frame N - condition
How do you want to define your end point?
Options: - duration (s) - duration (frames) - time (s) - frame N - condition
When does the component start?
When does the component end? (blank is endless)
(Optional) expected start (s), purely for representing in the timeline
(Optional) expected duration (s), purely for representing in the timeline
Store the onset/offset times in the data file (as well as in the log file).
Synchronize times with screen refresh (good for visual stimuli and responses based on them)
Disable this component
Units of dimensions for this stimulus
Options: - from exp settings - deg - cm - pix - norm - height - degFlatPos - degFlat
Position of this stimulus (e.g. [1,2] )
Size of this stimulus (either a single value or x,y pair, e.g. 2.5, [1,2]
Which point on the stimulus should be anchored to its exact position?
Options: - center - top-center - bottom-center - center-left - center-right - top-left - top-right - bottom-left - bottom-right
Foreground color of this stimulus (e.g. $[1,1,0], red )
In what format (color space) have you specified the colors? (rgb, dkl, lms, hsv)
Options: - rgb - dkl - lms - hsv
Opacity of the stimulus (1=opaque, 0=fully transparent, 0.5=translucent). Leave blank for each color to have its own opacity (recommended if any color is None).
OpenGL Blendmode. Avg is most common mode in PsychoPy, add is useful if combining a beat with the carrier image or numpy array at point of display
Options: - avg - add
Contrast of background carrier
Orientation of this stimulus (in deg)
Options: - -360 - 360
The (2D) texture of the background - can be sin, sqr, sinXsin… or a filename (including path)
Options: - sin - sqr - sinXsin
An image to define the alpha mask (ie shape)- gauss, circle… or a filename (including path)
Options: - gauss - circle
Spatial frequency of background carrier repeats across the grating in 1 or 2 dimensions, e.g. 4 or [2,3]
Spatial positioning of the background carrier (wraps in range 0-1.0)
Resolution of the texture for standard ones such as sin, sqr etc. For most cases a value of 256 pixels will suffice
Options: - 32 - 64 - 128 - 256 - 512
How should the image be interpolated if/when rescaled
Options: - linear - nearest
The (2D) texture of the envelope - can be sin, sqr, sinXsin… or a filename (including path)
Options: - sin - sqr - sinXsin
Spatial frequency of the modulation envelope repeats across the grating in 1 or 2 dimensions, e.g. 4 or [2,3]
Spatial positioning of the modulation envelope(wraps in range 0-1.0)
Orientation of the modulation envelope(wraps in range 0-360)
Modulation depth of modulation envelope
Power of modulation envelope. The modulator will be raised to this power according to the equation S=cC*(1+mM)^power, where C is the carrier and M is the modulator. and c and m are there respective contrast and modulation depth. Only works with AM envelopes (hence +1) in equation. Power is ignored if a beat is requested. This is used to obtain the square root of the modulator (power = 0.5) which is useful if combining two envelope gratings with different carriers and a 180 degree phase shift as the resulting combined signal will not have any reduction in local contrast at any point in the image. This is similar - but not identical to - the method used by Landy and Oruc, Vis Res 2002. Note overall contrast (apparent carrier contrast) will be altered.
Do you want a ‘beat’? [beat = carrier*envelope, no beat = carrier*(1+envelope), True/False, Y/N]