About Entrez
Text Version
Entrez PubMed
Overview
Help |
FAQ
Tutorial
New/Noteworthy
E-Utilities
PubMed Services
Journals Database
MeSH Database
Single Citation Matcher
Batch Citation Matcher
Clinical Queries
LinkOut
Cubby
Related Resources
Order Documents
NLM Catalog
NLM Gateway
TOXNET
Consumer Health
Clinical Alerts
ClinicalTrials.gov
PubMed Central
|
|
Color opponency is an efficient representation of spectral properties in natural scenes.
Lee TW, Wachtler T, Sejnowski TJ.
Institute for Neural Computation, University of California, San Diego, La Jolla, CA 92093-0523, USA. tewon@salk.edu
The
human visual system encodes the chromatic signals conveyed by the three
types of retinal cone photoreceptors in an opponent fashion. This
opponency is thought to reduce redundant information by decorrelating
the photoreceptor signals. Correlations in the receptor signals are
caused by the substantial overlap of the spectral sensitivities of the
receptors, but it is not clear to what extent the properties of natural
spectra contribute to the correlations. To investigate the influences
of natural spectra and photoreceptor spectral sensitivities, we
attempted to find linear codes with minimal redundancy for trichromatic
images assuming human cone spectral sensitivities, or hypothetical
non-overlapping cone sensitivities, respectively. The resulting
properties of basis functions are similar in both cases. They are
non-orthogonal, show strong opponency along an achromatic direction
(luminance edges) and along chromatic directions, and they achieve a
highly efficient encoding of natural chromatic signals. Thus, color
opponency arises for the encoding of human cone signals, i.e. with
strongly overlapping spectral sensitivities, but also under the
assumption of non-overlapping spectral sensitivities. Our results
suggest that color opponency may in part be a result of the properties
of natural spectra and not solely a consequence of the cone spectral
sensitivities.
PMID: 12169429 [PubMed - indexed for MEDLINE]
|