A new masking technique for natural scenes reveals the saliency of an image

Masking is a key experimental tool to precisely control the visibility of visual stimuli. We explore a new technique for masking images, in particular natural scenes: briefly flashing (e.g., 10 ms) a natural scene followed by a brief flash of a negative version of the same scene. The stimulus and its negative version are inversely related like a photo and its negative and can be obtained by subtracting the stimulus from the maximum palette entry in each respective color channel.