scholarly journals When luminance increment thresholds depend on apparent lightness

2013 ◽  
Vol 13 (6) ◽  
pp. 21-21 ◽  
Author(s):  
M. Maertens ◽  
F. A. Wichmann
Keyword(s):  
Luminance Increment ◽  
Apparent Lightness

scholarly journals When luminance increment thresholds depend on apparent lightness

2012 ◽  
Vol 12 (9) ◽  
pp. 1213-1213
Author(s):  
M. Maertens ◽  
F. Wichmann
Keyword(s):  
Luminance Increment ◽  
Apparent Lightness

Bipolar or rectified chromatic detection mechanisms?

2001 ◽  
Vol 18 (1) ◽  
pp. 127-135 ◽  
Author(s):  
MARCEL J. SANKERALLI ◽  
KATHY T. MULLEN
Keyword(s):  
Color Vision ◽  
Masking Effect ◽  
Yellow Light ◽  
Detection Thresholds ◽  
Noise Masking ◽  
Human Color Vision ◽  
Early Processing ◽  
The Cross ◽  
On And Off Pathways ◽  
Luminance Increment

It is widely accepted that human color vision is based on two types of cone-opponent mechanism, one differencing L and M cone types (loosely termed “red–green”), and the other differencing S with the L and M cones (loosely termed “blue–yellow”). The traditional view of the early processing of human color vision suggests that each of these cone-opponent mechanisms respond in a bipolar fashion to signal two opponent colors (red vs. green, blue vs. yellow). An alternative possibility is that each cone-opponent response, as well as the luminance response, is rectified, so producing separable signals for each pole (red, green, blue, yellow, light, and dark). In this study, we use psychophysical noise masking to determine whether the rectified model applies to detection by the postreceptoral mechanisms. We measured the contrast-detection thresholds of six test stimuli (red, green, blue, yellow, light, and dark), corresponding to the two poles of each of the three postreceptoral mechanisms. For each test, we determined whether noise presented to the cross pole had the same masking effect as noise presented to the same pole (e.g. comparing masking of luminance increments by luminance decrement noise (cross pole) and luminance increment noise (same pole)). To avoid stimulus cancellation, the test and mask were presented asynchronously in a “sandwich” arrangement (mask-test-mask). For the six test stimuli, we observed that noise masks presented to the cross pole did not raise the detection thresholds of the test, whereas noise presented to the same pole produced a substantial masking. This result suggests that each color signal (red, green, blue, and yellow) and luminance signal (light and dark) is subserved by a separable mechanism. We suggest that the cone-opponent and luminance mechanisms have similar physiological bases, since a functional separation of the processing of cone increments and cone decrements could underlie both the separation of the luminance system into ON and OFF pathways as well as the splitting of the cone-opponent mechanisms into separable color poles.

APPARENT LIGHTNESS

1966 ◽  
pp. 76-114
Author(s):  
RAYMOND J. SEEGER
Keyword(s):  
Apparent Lightness

3. On the Specific Gravity of certain Substances commonly considered lighter than Water

1845 ◽  
Vol 1 ◽  
pp. 424-426
Author(s):  
Davy
Keyword(s):  
Specific Gravity ◽  
Oak Wood ◽  
The Subject ◽  
The Common ◽  
Apparent Lightness

The author enters on the subject by adverting to the apparent lightness imparted to the common woods, and to certain vesicular minerals, by the entanglement of air in their substance, as is commonly understood, and as is proved by the action of the air-pump. The specific gravity of oak-wood, after having been kept under the exhausted receiver till it sunk in water, and ceased to give off air, he found to be (inclusive of hygrometric moisture) 1.58; that of deal, 1.18, or when crushed about 1.5; that of the pith of the elder, 1.45; and that of pumice, 1.94, or crushed, 2.41, which is nearly the same as that of obsidian, from which pumice appears to be formed by the action of volcanic fire.

Object-based visual attention in luminance increment detection?

1997 ◽  
Vol 35 (6) ◽  
pp. 843-853 ◽  
Author(s):  
Geoffrey W Stuart ◽  
Paul Maruff ◽  
Jon Currie
Keyword(s):  
Visual Attention ◽  
Object Based ◽  
Luminance Increment

Perceptual Organization and White's Illusion

Perception ◽  
10.1068/p3216 ◽  
2003 ◽  
Vol 32 (3) ◽  
pp. 269-284 ◽  
Author(s):  
Barton L Anderson
Keyword(s):  
Perceptual Organization ◽  
Context Dependence ◽  
Spatial Context ◽  
New Method ◽  
Low Level ◽  
New Evidence ◽  
Apparent Lightness

The apparent lightness of a surface can be strongly modulated by the spatial context in which it is embedded. Early theories of such context dependence emphasized the role of low-level mechanisms that sense border contrast, whereas a number of recent authors have emphasized the role of perceptual organization in determining perceived lightness. One of the simplest and most theoretically challenging lightness illusions was described by White. This illusion has been explained with a variety of different models, ranging from low-level filter outputs to computations underlying the extraction of mid-level representations of surfaces. Here, I present a new method for determining the organizational forces that shape this illusion. I show that the spatial context of White's pattern not only transforms the apparent lightness of homogeneous target patches, but can also induce dramatic inversions of figure–ground relationships of textured target regions. These phenomena provide new evidence for the role of scission in causing the lightness illusion experienced in White's effect.

Brightness Matching, Brightness Cancellation, and Increment Threshold in the Ehrenstein Illusion

Perception ◽  
1984 ◽  
Vol 13 (5) ◽  
pp. 513-520 ◽  
Author(s):  
Lothar Spillmann ◽  
Kenneth Fuld ◽  
Christa Neumeyer
Keyword(s):  
Detection Threshold ◽  
Receptive Fields ◽  
Negative Contrast ◽  
Positive Contrast ◽  
Relative Strength ◽  
Lateral Interaction ◽  
Test Flash ◽  
Increment Threshold ◽  
Small Test ◽  
Luminance Increment

Matching and cancellation techniques were used to measure the relative strength of the Ehrenstein illusion in dark figures on a light background (negative contrast) and light figures on a dark background (positive contrast). Brightness enhancement on the former was shown to be maximally 0.28 log unit (relative to the detection threshold), and darkness enhancement on the latter 0.43 log unit. Values differed little with figure–ground contrast (down to a minimum of ±0.5), but decreased with decreasing level of illumination. The luminance increment (decrement) needed to match the illusory brightness (darkness) was similar in size to the luminance decrement (increment) needed to cancel the illusion. The increment threshold for a small test flash measured in three locations relative to the subjective contour delineating the illusion did not differ systematically. The results are compatible with a neurophysiological explanation of the Ehrenstein illusion in terms of line-induced lateral interaction in hypercomplex receptive fields.

A Dugout Canoe from Ontario

1960 ◽  
Vol 25 (3) ◽  
pp. 417-418 ◽  
Author(s):  
Kenneth E. Kidd
Keyword(s):  
Shallow Water ◽  
Dugout Canoes ◽  
Apparent Lightness

AbstractIn recent years several dugout canoes have been found in Ontario, but details are lacking for most. One raised from shallow water at Balsam Lake is badly eroded and appears to be of some antiquity. It is a sleek craft of unusual length, remarkably slim proportions and contour, and considerable rigidity, despite its apparent lightness in proportion to its size, because of its substantial bow and stern.

Phenomena of Apparent Lightness Interpreted by the Recognized Visual Space of Illumination

1998 ◽  
Vol 5 (6) ◽  
pp. 380-386 ◽  
Author(s):  
Mitsuo Ikeda ◽  
Hiroyuki Shinoda ◽  
Yoko Mizokami
Keyword(s):  
Visual Space ◽  
Apparent Lightness
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