this study was conducted to determine the use of three-dimensional ultrasonography (3du) in ocular imaging of the dog and measuring of its optical axis. 12 healthy mixed-breed dogs including 6 males and 6 females were studied. 3du of the eyes were done using a 5–12 mhz linear trapezoid transducer. 3du of the eyes were evaluated and the normal optical long axis through a line between the cornea ...

The spectral resolution is a main index of evaluating the performance of the designed acousto-optic tunable filter (AOTF). In this letter, an accurate expression of the spectral resolution is presented by considering both the birefringence and the rotatory property of TeO2 crystal. The deduced expression is significant in improving the accuracy of the design of an AOTF and pushing the developme...

Recently we presented acousto-optic (AO) probing of scattering media using addition or subtraction of speckle patterns due to tandem nanosecond pulses. Here we present a theoretical framework for ideal (polarized, noise-free) speckle patterns with unity contrast that links ultrasound-induced optical phase modulation, the fraction of light that is tagged by ultrasound, speckle contrast, mean squ...

The field of depth recovery from optic flow has recently experienced much growth, both on the theoretical and on the empirical fronts. Unfortunately, the theoretical results are not as widely known to perception workers as they might be. This article gives a simple analysis of the information for depth present in optic flow. It also reviews the psychophysical results for depth recovery from mot...

Optic flow provides important information for the perception of self-motion and can be generated by both diffuse and specular reflectance. Previous self-motion research using virtual environments has primarily considered the properties of diffuse optic flow, but not of specular flow. We used graphical simulations to examine the extent to which visually induced self-motion (vection) is robust ag...

Experience has long-term effects on perceptual appearance (Q. Haijiang, J. A. Saunders, R. W. Stone, & B. T. Backus, 2006). We asked whether experience affects the appearance of structure-from-motion stimuli when the optic flow is caused by observer ego-motion. Optic flow is an ambiguous depth cue: a rotating object and its oppositely rotating, depth-inverted dual generate similar flow. However...

How do animals and insects use visual information to move through the world successfully? Optic flow, the pattern of motion at the eye, is a powerful source of information about self-motion. Insects and humans are sensitive to the global pattern of optic flow and try to maintain flow symmetry when flying or walking. The environments humans encounter, however, often contain demarcated paths that...

AIM To characterise measurement variability in scanning laser tomography of the optic nerve head. METHODS 21 normal and 21 glaucoma subjects underwent same and separate day test-retest Heidelberg retina tomograph imaging by the same and different operators. RESULTS Rim area was most reproducible among parameters. Its variability tended to be highest temporally and increased (p<0.05) with te...

Use of motion to break camouflage extends back to the Cambrian [In the Blink of an Eye: How Vision Sparked the Big Bang of Evolution (New York Basic Books, 2003)]. We investigated the ability to break camouflage and continue to see camouflaged targets after motion stops. This is crucial for the survival of hunting predators. With camouflage, visual targets and distracters cannot be distinguishe...

Visual perception studies typically focus either on optic flow structure or image structure, but not on the combination and interaction of these two sources of information. Each offers unique strengths in contrast to the other's weaknesses. Optic flow yields intrinsically powerful information about 3D structure, but is ephemeral. It ceases when motion stops. Image structure is less powerful in ...