Foveal crowding for large and small Landolt Cs: Similarity and Attention.

We compare the recognition of foveal crowded Landolt Cs of two sizes: brief (40 ms), large, low-contrast Cs and high-contrast (1 sec) tests at the resolution limit of the visual system. In different series, the test Landolt C was surrounded by two identical distractors located symmetrically along the horizontal or by a single distractor. The distractors were Landolt Cs or rings.

[Noise affect to the fragmented contour image recognition].

We performed a comparison of the results of recognition of fragmented outline images in the presence of noise and without it. Contour images and visual noise were synthesized form Gabor elements. Distances between the Gabor elements in contour and in noise were changed and image sizes varied too.

[Estimates of the size of inhibitory areas in crowding effects in periphery].

In psychophysical experiments we studied how surround influences recognition of test objects. The tests were low-contrast Landolt rings of the size 1.1, 1.

Complexity of images: experimental and computational estimates compared.

We tested whether visual complexity can be modeled through the use of parameters relevant to known mechanisms of visual processing. In psychophysical experiments observers ranked the complexity of two groups of stimuli: 15 unfamiliar Chinese hieroglyphs and 24 outline images of well-known common objects. To predict image complexity, we considered: (i) spatial characteristics of the images, (ii) spatial-frequency characteristics, (iii) a combination of spatial and Fourier properties, and (iv) the size of the image encoded as a JPEG file.

[Acuity and hyperacuity for pupils of 11-17 years old].

Estimations of hyperacuity and visual acuity (VA) have been compared in schoolchildren aged 11-17 years with normal vision. VA was measured using Landolt Cs and Tumbling Es. Hyperacuity was measured by vernier stimuli.