| |
Records |
Links |
|
Author |
C. Alejandro Parraga; Jordi Roca; Maria Vanrell |
|
| |
Title |
Do Basic Colors Influence Chromatic Adaptation? |
Type |
Journal Article |
| |
Year |
2011 |
Publication |
Journal of Vision |
Abbreviated Journal |
VSS |
|
| |
Volume  |
11 |
Issue |
11 |
Pages |
85 |
|
| |
Keywords |
|
|
| |
Abstract |
Color constancy (the ability to perceive colors relatively stable under different illuminants) is the result of several mechanisms spread across different neural levels and responding to several visual scene cues. It is usually measured by estimating the perceived color of a grey patch under an illuminant change. In this work, we hypothesize whether chromatic adaptation (without a reference white or grey) could be driven by certain colors, specifically those corresponding to the universal color terms proposed by Berlin and Kay (1969). To this end we have developed a new psychophysical paradigm in which subjects adjust the color of a test patch (in CIELab space) to match their memory of the best example of a given color chosen from the universal terms list (grey, red, green, blue, yellow, purple, pink, orange and brown). The test patch is embedded inside a Mondrian image and presented on a calibrated CRT screen inside a dark cabin. All subjects were trained to “recall” their most exemplary colors reliably from memory and asked to always produce the same basic colors when required under several adaptation conditions. These include achromatic and colored Mondrian backgrounds, under a simulated D65 illuminant and several colored illuminants. A set of basic colors were measured for each subject under neutral conditions (achromatic background and D65 illuminant) and used as “reference” for the rest of the experiment. The colors adjusted by the subjects in each adaptation condition were compared to the reference colors under the corresponding illuminant and a “constancy index” was obtained for each of them. Our results show that for some colors the constancy index was better than for grey. The set of best adapted colors in each condition were common to a majority of subjects and were dependent on the chromaticity of the illuminant and the chromatic background considered. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1534-7362 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
CIC |
Approved |
no |
|
| |
Call Number |
Admin @ si @ PRV2011 |
Serial |
1759 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
O. Fors; J. Nuñez; Xavier Otazu; A. Prades; Robert D. Cardinal |
|
| |
Title |
Improving the Ability of Image Sensors to Detect Faint Stars and Moving Objects Using Image Deconvolution Techniques |
Type |
Journal Article |
| |
Year |
2010 |
Publication |
Sensors |
Abbreviated Journal |
SENS |
|
| |
Volume |
10 |
Issue |
3 |
Pages |
1743–1752 |
|
| |
Keywords |
image processing; image deconvolution; faint stars; space debris; wavelet transform |
|
| |
Abstract |
Abstract: In this paper we show how the techniques of image deconvolution can increase the ability of image sensors as, for example, CCD imagers, to detect faint stars or faint orbital objects (small satellites and space debris). In the case of faint stars, we show that this benefit is equivalent to double the quantum efficiency of the used image sensor or to increase the effective telescope aperture by more than 30% without decreasing the astrometric precision or introducing artificial bias. In the case of orbital objects, the deconvolution technique can double the signal-to-noise ratio of the image, which helps to discover and control dangerous objects as space debris or lost satellites. The benefits obtained using CCD detectors can be extrapolated to any kind of image sensors. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
|
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
CIC |
Approved |
no |
|
| |
Call Number |
CAT @ cat @ FNO2010 |
Serial |
1285 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Xavier Otazu; C. Alejandro Parraga; Maria Vanrell |
|
| |
Title |
Towards a unified chromatic inducction model |
Type |
Journal Article |
| |
Year |
2010 |
Publication |
Journal of Vision |
Abbreviated Journal |
VSS |
|
| |
Volume |
10 |
Issue |
12:5 |
Pages |
1-24 |
|
| |
Keywords |
Visual system; Color induction; Wavelet transform |
|
| |
Abstract |
In a previous work (X. Otazu, M. Vanrell, & C. A. Párraga, 2008b), we showed how several brightness induction effects can be predicted using a simple multiresolution wavelet model (BIWaM). Here we present a new model for chromatic induction processes (termed Chromatic Induction Wavelet Model or CIWaM), which is also implemented on a multiresolution framework and based on similar assumptions related to the spatial frequency and the contrast surround energy of the stimulus. The CIWaM can be interpreted as a very simple extension of the BIWaM to the chromatic channels, which in our case are defined in the MacLeod-Boynton (lsY) color space. This new model allows us to unify both chromatic assimilation and chromatic contrast effects in a single mathematical formulation. The predictions of the CIWaM were tested by means of several color and brightness induction experiments, which showed an acceptable agreement between model predictions and psychophysical data. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
|
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
CIC |
Approved |
no |
|
| |
Call Number |
CAT @ cat @ OPV2010 |
Serial |
1450 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Maria Vanrell; Jordi Vitria; Xavier Roca |
|
| |
Title |
A multidimensional scaling approach to explore the behavior of a texture perception algorithm. |
Type |
Journal Article |
| |
Year |
1997 |
Publication |
Machine Vision and Applications |
Abbreviated Journal |
|
|
| |
Volume |
9 |
Issue |
|
Pages |
262–271 |
|
| |
Keywords |
|
|
| |
Abstract |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
|
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
OR;ISE;CIC;MV |
Approved |
no |
|
| |
Call Number |
BCNPCL @ bcnpcl @ VVR1997 |
Serial |
35 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Judit Martinez; Eva Costa; P. Herreros; F. Javier Sanchez; Ramon Baldrich |
|
| |
Title |
A Modular and Scalable Architecture for PC-Based Real-Time Vision Systems |
Type |
Journal Article |
| |
Year |
2003 |
Publication |
Real–Time Imaging, (IF: 0.512) |
Abbreviated Journal |
|
|
| |
Volume |
9 |
Issue |
|
Pages |
99-112 |
|
| |
Keywords |
|
|
| |
Abstract |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
|
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
CIC |
Approved |
no |
|
| |
Call Number |
CAT @ cat @ MCH2003b |
Serial |
394 |
|
| Permanent link to this record |
