Thesis-1995-Kuo.pdf (5.32 MB)
Quantification of metamerism and colour constancy
thesis
posted on 2014-07-29, 10:39 authored by Wen-Guey KuoReliable colour constancy
by industry for colour
conducted to quantify
metamerism.
and metamerism indices are highly desired
quality control. Two experiments were
the degree of colour constancy and
In the colour constancy experiment, 240 wool samples were
prepared and scaled using a magnitude estimation method by a
panel of 5 experienced observers under sources D65, A and TL84. 2
corresponding data sets derived from the experimental results were
used to test various chromatic adaptation transforms. The results
clearly show that the BFD transform gave the most precise prediction
than the other transforms. Attempts were also made to derive 4 new
transforms from four independent data sets. These gave similar
performance as that of the BFD, but overcome the BFO's problem
(incapable of predicting some of the high saturated colours). Hence,
these transforms should be used with confidence for predicting the
degree of colour constancy.
This experimental results were also used to test various
uniform colour spaces and colour appearance models. The Hunt94
model gave the most precise prediction to the colourfulness and hue
results. Modification was made to its lightness scale for improving
the fit.
In the metamerism experiment, 76 pairs of wool samples were
prepared and assessed with 20 observations using a grey scale under
7 sources: D65, A, TL84, TL83, P27, W and WW. The experimental
results were used to test 3 types of illuminant metamerism indices
derived here. It was found that calculating colour difference using 3
colour difference formulae, i.e. CMC, BFD and CIE94 gave the most
precise prediction to the visual results. The degree of precision is
quite satisfactory in comparison with typical observer precision.
A new standard deviate observer (SDO) was also derived. This
together with the CIE SDO and 1964 Observer were tested using the
author's and the Obande's data. The results showed that the new SDO
predicted results more accurate than those from the other two CIE
Observers. An Observer Metamerism Index (OMI) was also derived
to indicate the degree of metamerism based upon the new SDO. The
results showed that the new SDO was more suitable for indicating the
degree of observer metamerism.
History
School
- Science
Department
- Computer Science
Publisher
© Wen-Guey KuoPublication date
1995Notes
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.EThOS Persistent ID
uk.bl.ethos.283982Language
- en