Introducing blur into the color components of a natural scene has very little effect on its percept, whereas blur introduced into the luminance component is very noticeable. Here we quantify the dominance of luminance information in blur detection and examine a number of potential causes. We show that the interaction between chromatic and luminance information is not explained by reduced acuity...

For each session of the experiments, the staircases reached stable luminance levels after approximately 200 trials (Supplementary figure 1). A slow luminance descent was used to allow bigger variations in participants' performance and color sensitivity, as a few participants had significantly higher threshold levels than the average. Additionally, green dots were expected to be easier to detect...

The spatial resolution of disparity perception is poor compared to luminance perception, yet we do not notice that depth edges are more blurry than luminance edges. Is this because the two cues are combined by the visual system? Subjects judged the locations of depth-defined or luminance-defined edges, which were separated by up to 5.6 min of arc. The perceived edge location was a function of t...

The luminance-response function of the brief flash full-field photopic electroretinogram (ERG) rises to a peak before falling to a sub-maximal plateau -- the 'photopic hill'. The combination of on- and off-responses inherent in the brief flash photopic ERG suggests that this luminance-response function could be modelled by the sum of a Gaussian function and a logistic growth function. Photopic ...

The luminance of a test within an inhomogeneous ("checkerboard") surround was adjusted to match the brightness of a comparison patch within a uniform surround. All stimuli were achromatic. Both surrounds had the same space-averaged luminance. With an incremental comparison patch, a test-within-checkerboard at a luminance between the luminances of the brighter and dimmer checks appears dimmer th...

The Café Wall illusion (seen on the tiles of a local café) is a Münsterberg chequerboard figure, but with horizontal parallel lines which may have any luminance separating the rows of displaced squares. These (the 'mortar' lines) display marked wedge distortion which is especially affected by: contrast of the squares ('tiles'); width of the 'mortar' lines, and their luminance which must not be ...

We have tested the independence of red-green chromatic and luminance mechanisms at detection threshold using a method of subthreshold summation. Stimuli were isoluminant red-green gratings and yellow-black luminance gratings that uniquely activate the red-green color and luminance mechanisms, respectively. Stimuli were Gaussian enveloped 0.25, 1 or 4 cpd sinewave gratings, counter-phase flicker...

Perceived depth is conveyed by multiple cues, including binocular disparity and luminance shading. Depth perception from luminance shading information depends on the perceptual assumption for the incident light, which has been shown to default to a diffuse illumination assumption. We focus on the case of sinusoidally corrugated surfaces to ask how shading and disparity cues combine defined by t...

As the eye changes focus, the resulting changes in cone contrast are associated with changes in color and luminance. Color fluctuations should simulate the eye being hyperopic and make the eye grow in the myopic direction, while luminance fluctuations should simulate myopia and make the eye grow in the hyperopic direction. Chicks without lenses were exposed daily (9 a.m. to 5 p.m.) for three da...

This study aimed to identify the luminance and contrast levels necessary to minimise the threshold identification size of bright letters displayed over a dark background on an LCD under low (1.5 lux) and high (260 lux) lighting conditions. White, pure red, pure green and pure blue upper-case Bailey Lovie letters with a contrast between 3:1 and 300:1 were displayed on an LCD to 20 participants. ...