The development of the OCTA toolbox:
An accessible, open-source tool to create
flexible and reproducible visual displays

Eline Van Geert, Christophe Bossens, & Johan Wagemans
Laboratory of Experimental Psychology, KU Leuven, Belgium

Aim of OCTA

Create reproducible and flexible multi-element displays varying qualitatively and quantitatively in:

ORDER
order
structure and organization
COMPLEXITY
complexity
quantity and variety

available as a free tool for
programmers (as a Python library) and
non-programmers (as an online Shiny app)

1 Create stimulus  &   2 Add positions

Specify stimulus type (Grid, Outline, Concentric)
and stimulus features (e.g., orientation, background color)

Specify position pattern for elements


Create2DGrid

CreateSineGrid

CreateRandomPositions

CreateCircle

CreateShape

CreateCustomPositions

Test OCTA











Shiny app    documentation    Python code

stimulus generation tool for researchers
but can also be used by broader public
to easily create interesting visual displays

3 Add feature patterns and pattern values  &   4 Add deviations  &   5 Save and recreate the stimulus

Features (including dynamic feature options!)

shapes

fillcolors

boundingboxes

orientations

borderwidths

bordercolors

opacities

mirrorvalues

additional non-visual features: links, classlabels, idlabels

Pattern types

Repeat

ElementRepeat

Mirror

Gradient



Random

TiledGrid

TiledElementGrid
Pattern directions

AcrossElements

AcrossRows

AcrossColumns



AcrossLeftDiagonal

AcrossRightDiagonal

AcrossLayers
Position and element deviations

position
jitter

position
deviations

swap
elements

randomize
elements

remove
elements
Feature deviations

swap
features

change
features

randomize
features

jitter
features
Output options
  • stimulus as vector or raster image
  • computer-readable output to recreate the stimulus in Python with the LoadFromJSON function
  • in the online app: download or view the Python code

Interactive online applications

Make research data available for exploration by a broader audience in an easy and interactive way: OCTA ratings app


Why use OCTA?

OCTA facilitates reproducible stimulus construction and experimental design in
research on aesthetics and visual perception
Use OCTA when you want to create stimuli that are:
  • varying qualitatively or quantitatively in order and/or complexity
  • reproducible, adjustable, and open source
  • easy to create
  • tailored for online use
  • static or dynamic
  • multimodal (adding sound is possible using Javascript)
Many opportunities for further development

Subscribe to email updates on OCTA here

Get in touch for questions, feature requests,
or collaborations!
eline.vangeert@kuleuven.be
Animated online version of poster:

Contact

Eline Van Geert - eline.vangeert@kuleuven.be
supported by a Ph.D. fellowship of the Research Foundation - Flanders (FWO)
GestaltReVision logo

DigiSoc Launch Event 2021 - October 26th - Leuven

The OCTA Shiny app