This paper investigates intensity coding in human vision. Specifically, we address the following question: how do different luminances influence the perceived total luminance of a composite image? We investigate this question using a paradigm in which the observer attempts to judge, with feedback, which of two texture patches has higher total luminance. All patches are composed of nine luminanc...

375 Although attention profoundly alters visual perception1, it is not equally important to all aspects of vision. For example, attention is of little or no help to many detection tasks (for example, detecting a luminance increment2), and the degree to which it benefits discrimination tasks varies widely with the discriminated attribute (for example, discriminating color, orientation, form3,4)....

One of the important task in most of Content Based Image Retrieval(CB1R) system is similarity matching. Similarity matching requires distance computation of feature vectors for each candidate image in image database. Conventional algorithms based on exhaustive search are highly time consuming and inefficient. With rapid increase in database size, there is a growing need of a fast and efficient ...

Projectors suffer from nonuniformity across the display, as well as spurious contours due to insufficient levels. This work offers an efficient and accurate solution to both problems. A camera-based calibration scheme both measures the spatial luminance nonuniformity and detects the projected levels that are unique. Using this data, an attenuation array is built using reverse-3D-table lookup. T...

Luminance and contrast are two major attributes of objects in the visual scene. Luminance and contrast information received by visual neurons are often updated simultaneously. We examined the temporal response properties of neurons in the primary visual cortex (V1) to stimuli whose luminance and contrast were simultaneously changed by 50 Hz. We found that response tuning to luminance changes pr...

It has been demonstrated widely that at isoluminance moving chromatic stimuli are seen to be stationary or moving more slowly than their luminance counterparts. We have examined the effect on perceived velocity of adding luminance contrast to an isoluminant chromatic stimulus. We show that moving luminance contrast 'captures' colour so that a combined colour and luminance stimulus is seen movin...

We investigated the interactions between flicker thresholds and luminance pedestals using threshold versus contrast (TvC) and method of constant stimuli paradigms. High amplitude luminance pedestals were found to elevate flicker thresholds, but low amplitude luminance pedestals were unable to reduce flicker thresholds. Luminance pedestals elevated flicker thresholds more at low temporal frequen...