Comparison of color and luminance contrast: apples versus oranges?
نویسندگان
چکیده
Using a spatial, forced-choice, matching protocol, we have measured observers' ability to equate the contrasts of sinusoidal gratings which vary along differing directions in a 3-dimensional color space. In a given experiment, the observer obtained a perceptual match between the contrasts of two gratings whose chromaticities or luminances varied along differing chromatic directions which were selected from among five axes: an achromatic luminance axis (lum), an isoluminant axis where only S-cone activation varied (S-axis), an isoluminant axis where L- and M-cone activation varied in a complementary manner (LM-axis), an axis where only L-cone activation varied (L-axis), and an axis where only M-cone activation varied (M-axis). Even though these chromatic axes were chosen to activate independent mechanisms involved in the early stages of spatiochromatic visual processing, and despite the distinctly differing appearance of patterns from variations along differing directions, we find that observers can reliably make such pairwise contrast matches. Furthermore there is reasonable consistency of matching contrasts among observers and the pairwise contrast matches exhibit the properties of homogeneity and transitivity. This observed homogeneity and transitivity allows, for each color direction, the specification of a single scaling factor which relates perceptual contrast to physical contrast.
منابع مشابه
Contrast salience across three-dimensional chromoluminance space
We have extended previously studies of relative contrast salience [Switkes & Crognale, 1999. Comparison of color and luminance contrast: apples versus oranges? Vision Res. 39 (10), 1823-1831] to chromaticities intermediate to cardinal chromatic axes. We find that: (i) observers can reliably match the perceptual contrast of gratings differing in chromoluminance irrespective of whether they lie a...
متن کاملComparing apples and oranges: a randomised prospective study.
For many years the comparison of apples and oranges was thought to be impossible. Many authors use the analogy of the putative inability to compare apples and oranges as a means of scornfully reviewing the work of others. The titles of some recent publications 2 suggest an actual comparison of apples and oranges, but the authors do not, in fact, compare these two fruits. Our laboratory has been...
متن کاملHow not to give a presentation.
At first glance, some papers seemed to have addressedthe important topic of a real comparison of apples and oranges. Table 3 reveals the truth. This article, certain to become the classic in the field, clearly demonstrates that apples and oranges are not only comparable; indeed they are quite similar. The admonition “Let’s not compare apples with oranges” should be replaced immediately with a m...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Vision Research
دوره 39 شماره
صفحات -
تاریخ انتشار 1999