A rectangular or sinusoidal grating. Default is a grayscale grating that oscillates between pure black and white in a square area. Includes an option for drift behind a mask element. For a fully static Gabor (sinusoidal grating with Gaussian envelope) see element type gabor.

No—runs until any condition you set in property end.

shape

Default: sinusoidal

A string <cds>"rectangle"<cds> or <cds>"sine"<cds> setting form of the grating (rectangular or sinusoidal).

size

Default: square with sides 5 deg

Sets display area for the grating. A number that is side length for a square, or a vector [width height] for a rectangle (deg).

frequency

Default: 2 cycles/deg

Spatial frequency (cycles/deg).

orientation

Default: sine grating left → right (vertical bars)

Orientation angle of the grating, + = clockwise (deg). 0 = sine grating left → right (vertical bars). This sets rotation of the grating within its rectangular display area. For rotation of the whole display use property rotation.

phase

Default: sine grating with angle = 0 at center

Phase of grating (cycles). 0 = sine grating with angle = 0 at display center, 0.5 = negative sine grating, 0.25 = cosine grating, etc. Display center is at element position.

meanIntensity
amplitude
contrast

Defaults: meanIntensity = 0.5, amplitude = 0.5

meanIntensity is a number between 0–1 (black–maximum) setting the pixel intensity the grating oscillates about.

Also set one of:

amplitude is max intensity − mean intensity.

OR

contrast is Michelson contrast, amplitude / mean intensity. If you set contrast, mean intensity must be > 0.

It's possible to set a combination of these properties that causes the grating to clip at intensity 0 or 1. See record properties maxAmplitude and maxContrast below.

color

Default: white

A 1×3 RGB vector with numbers between 0–1. This defines the color at pixel intensity = 1. Color at intensity = 0 is <cd>[0 0 0]<cd>. Color at all other intensities is linearly interpolated between the two.

driftVelocity

Default: no drift

Use this property if you want to show a drifting grating behind a mask. This is a drift velocity (+ = direction of orientation above, − = opposite, deg/sec). If you set this, the grating will move in the specified direction at that speed and switch back to its starting position each time it moves one spatial period (1/frequency above). The size of the grating will also be padded on each side by one spatial period (without affecting spatial frequency). If you also run a mask element at the same position as the grating, the resulting display will be a drifting grating.

position
nn_eyes
rotation
colorMask
alpha
intensity
contrastMult
drawCodeVars

maxAmplitude
maxContrast

Values for input properties amplitude and contrast that would cause intensity to clip at 0 or 1 given the current value of meanIntensity.