A second novel feature of the experiments is the use of synthetic textured images (see
Figure 1a). These are periodic, so as to avoid edge effects when modifying images in the Fourier domain, and have strongly non-random phase spectra while being spatially homogeneous in appearance. They therefore have the advantage over photographic images of natural scenes that they contain no images of identifiable objects, and so effects of image content on the detectability of changes in spectra, such as those identified by Peli and Geri (
2001), can be eliminated. While the identification of objects in natural scenes is one important function of vision, perception of properties of textures such as gradients, discontinuities, and local anomalies is also important for natural tasks such as object (Christensen & Todd,
2004) and scene (Renninger & Malik,
2004) recognition, depth and slant perception, camouflage (Billock, Cunningham, & Tsou,
2008), and illumination estimation (Chantler & Delguste,
1997). Moreover, the perception of texture often appears to be an automatic, effortless task (Landy & Graham,
2004), and except perhaps for the case of examining expensive consumer goods, we rarely examine textures actively using foveal vision. Therefore, it is of interest to study how well our visual system can recover information about texture with short display times and away from the fovea.