checkerboard

 elements

A checkerboard pattern, including option for flicker.

▸ Object ends on its own?

"Ends on its own" means ends automatically at that point. 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 any condition you set in property end.

Input properties

Adjustable properties

You can vary or allow the subject to adjust the following properties of an object of this type when it's running. If you need to make other properties adjustable, you can edit the element type code—see Element Type Programming Manual.

Adjustable properties

Adjustable properties

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

position

Input properties all adjuster elements have

adjust

Input properties all objects have

report
info

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 using 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.