About this Research Topic
Optical scientists have measured how intraocular glare affects the image on the retina. Neural processes make spatial comparisons at every stage along the visual pathway. Both glare and neural processing alter visual response to scene radiances. Neural processing acts to cancel in part the impact of glare. The reduction of glare effects represents a new type of object constancy.
Studies of impaired-vision and cataracts measured the Glare Spread Function in eyes. In everyday experience, outside the effects of solar and headlight glare we usually do not notice it, so we might assume that glare is negligible. Scientists carefully record scene radiances for their model’s input. We must avoid the unarticulated assumption that the spatial array of scene radiances is equal to the spatial array of retinal radiances. Colorimetry and thresholds (detection and increment) using spots with no other source of straylight can work without calculating the retinal radiance image. Real-life images have variable, and unpredictable, scene content. Real images have High Dynamic Range (HDR) because of nonuniform illumination. Every “pixel” in a scene contributes small glare to every other pixel. Glare is the sum of millions of these small, and very small contributions.
Recent calculations of retinal images (in normal eyes) show large changes compared to the scene radiance distribution. Further, these calculations show the strong influences of scene content. In other words, objects with a given scene radiance become different retinal radiances due to optical glare from other parts of the scene. While glare is a part of all optics, it is remarkable that humans with normal vision usually do not observe its effects, even from scenes with considerable spatial transformation of scene radiances (beach scenes).
The current realization is that:
1. Scatter lowers the contrast of the scene’s image on the retina.
2. Scene-dependent neural spatial processing generates higher apparent contrast sensations from low-contrast retinal images.
A second, highly related, part of this Research Topic is HDR Imaging. Electronic Imaging can perform spatial image processing. It can reproduce the appearance of scenes, rather than attempting to capture and reproduce scene radiances. Glare in camera optics, similar to the glare in the eye, limits the dynamic range of light on the camera’s sensor. This Research Topic includes papers on the limits of camera scene capture, and the need and approaches for spatial image processing for improving camera performance.
This Research Topic is the multidisciplinary intersection of:
• perceptual constancy from the retinal glare plus post-receptor neural processing;
• computer programs to convert scene radiances to retinal images;
• models of vision using retinal radiances;
• measurement of appearances in HDR scenes;
• HDR scene capture and image processing.
This topic includes clinical eye care, neuroscience, visual psychophysics, models of appearance, digital imaging and processing, and digital camera design. All are essential components of a human’s response to light in real scenes. This is a new topic in visual appearance; its results will be of great interest.
See “Glare in Vision” for links to Reviews of related literature: http://mccannimaging.com/Glare_in_Vision/Introduction.html
Keywords: Glare, Eye Care, Neural processing, Appearance, High-Dynamic-Range (HDR) imaging
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.