Histogram Equalization (HE) is a simple and effective image enhancement technique.But, it tends to change the mean brightness of the image to the middle level of the permitted range, and hence is not a very suitable for consumer product. While preserving the original brightness is essential to avoid annoying artefacts. To preserve brightness and to enhance contrast of images, numerous methods a...

Several brightness illusions indicate that borders can affect the perception of surfaces dramatically. In the Cornsweet illusion, two equiluminant surfaces appear to be different in brightness because of the contrast border between them. Here, we report the existence of cells in monkey visual cortex that respond to such an "illusory" brightness. We find that luminance responsive cells are locat...

This paper reviews the brightness and coherence properties of radiation from storage rings and free electron lasers (FELs). Starting from the statistical optics and using mutual coherence function of the radiation field, we define the transverse and temporal coherence and modes. Spectral brightness can be represented in radiation phase-space via the Wigner function which is the Fourier transfor...

Subjects matched the brightness of test patches located within a larger surround, where the surround was made to appear either different in reflectance from neighboring regions, or of the same reflectance but viewed beneath a transparent film. In both conditions the luminance and spatial extent of the immediate surround was equivalent, thus controlling for the effects of local contrast. Perceiv...

In this paper we present a method to obtain corresponding contour features in a sequence of images. Our final goal is to compute camera motion and structure, for navigation based on vision. We make a feature tracking in the image considering not only the contour geometric information, but also a brightness-based description. A kinematic model of brightness attributes has been proposed in order ...

To capture the full brightness range of natural scenes, cameras automatically adjust the exposure value which causes the brightness of scene points to change from frame to frame. Given such a video sequence, we introduce an adaptive stereo system that automatically generates texture-mapped 3D models. The key part of the system is a new method for tracking features and estimating the radiometric...

Our visual systems account for stimulus context in brightness perception, but whether such adjustments occur for stimuli that we are unaware of has not been established. We therefore assessed whether stimulus context influences brightness processing by measuring unconscious priming with metacontrast masking. When a middle-gray disk was presented on a darker (or brighter) background, such that i...

We examined the spatial integration of simultaneously induced achromatic contrast and compared it to the spatial integration of simultaneously induced brightness. This study extends the work of Zaidi et al. [(1992). Vision Research, 32, pp. 1695-1707], who showed that the total magnitude of induced brightness can be described as the weighted sum of the brightness induced by individual elements ...

We demonstrate an anode concept, based on a liquid-metal jet, for improved brightness in compact electron-impact x-ray sources. The source is demonstrated in a proof-of-principle experiment where a 50 keV, ;100 W electron beam is focused on a 75 mm liquid-solder jet. The generated x-ray flux and brightness is quantitatively measured in the 7–50 keV spectral region and found to agree with theory...

We report a patient with extensive brain damage in the right hemisphere who demonstrated a severe impairment in the appreciation of brightness. Acuity, contrast sensitivity as well as luminance discrimination were normal, suggesting her brightness impairment is not a mere consequence of low-level sensory impairments. The patient was not able to indicate the darker or the lighter of two grey squ...