Abstract
Continuous flash suppression (CFS) is a popular masking technique widely used in vision research. By presenting a rapidly changing stimulus to one eye (the ‘mask’), a static image viewed by the other (the ‘target’) may remain suppressed from awareness for many seconds. Because of this, the suppressed image can be easily probed to assess unconscious visual processing, a question of broad interest in basic and clinical sciences. The spatio-temporal properties of the CFS mask and target affect the strength of interocular suppression, but the lack of principled stimulus selection has compromised generalisation of results across studies. To redress this, we created CFS-Crafter, a point-and-click, open-source tool for creating carefully controlled CFS stimuli. CFS-Crafter provides a streamlined workflow to create, modify and analyse (spatial and temporal frequency content, orientation, etc.) mask and target stimuli. Users can select CFS masks ranging from classic Mondrian patterns to those comprising objects or faces, or upload and analyse their own images. Mask and target images are analysed using image-processing operations performed in the frequency domain or can be custom made from noise images using spatial/temporal/orientation filtering and phase scrambling. CFS-Crafter thus offers controlled creation, analysis and comparison of customised images and can be used to analyse images from previous studies. CFS-Crafter – with its easy-to-use image processing functionality – will facilitate the use of CFS while strengthening the claims and conclusion that stem from it.