checkerboard
elements
A checkerboard pattern, including option for flicker.
▸ Object ends on its own?
If an element can end on its own, you don't need to set end conditions for it in property end (unless you want it to maybe end earlier).
No—runs until a condition you set in property end.
Input properties
Adjustable properties
You can vary or allow the subject to adjust the following input properties of an object of this type in real time when it's running. If you need to make other properties adjustable, you can edit the element type code—see Element Type Programming Manual.
position
nn_eyes
rotation
colorMask
alpha
intensity
contrastMult
drawCodeVars
(None)
(None)
size
Default: square with sides 10 deg
A number that is side length for a square checkerboard, or a vector [width height] for a rectangle (deg).
numChecks
Default: 20 square checks in the checkerboard width
Number of checks in the checkerboard in the x (width) direction. Number of checks in the y (height) direction is then automatic to give square checks.
Or a vector [n_x n_y] setting number of checks in the width/height directions independently. You can use this if you want non-square checks.
phase
Default: immediate check in quadrant 1 = light
0/1 setting the initial pattern: 0 = check immediately right and below element display center = dark, 1 = light. Note currently the checkerboard is always centered at element position, with the corners of four checks at that point. Element position can be set in property position.
meanIntensity
amplitude
contrast
Defaults: meanIntensity = 0.5, amplitude = 0.5
meanIntensity is a number between 0–1 (black-maximum) setting the mean intensity of light and dark checks.
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 checkerboard 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 intensity = 1. Color at intensity = 0 is <cd>[0 0 0]<cd>. Color at all other intensities is linearly interpolated between the two.
flickerFrequency
Default: no flicker
Frequency of switching between dark–light (cycles/sec). 0 = no flicker.
Input properties all visual elements have
Input properties all adjuster elements have
Input properties all objects have
Record properties
PsychBench uses record properties to record information during experiments. You can't set record properties but you can see them in experiment results by listing them input property report.
maxAmplitude
maxContrast
Maximum amplitude and contrast where intensity would clip at 0 or 1, whichever is reached first, given the set mean intensity.