Boots – shoes – and leggings
Patent
1991-04-30
1993-01-05
Lall, Parshotam S.
Boots, shoes, and leggings
356421, G01N 2125
Patent
active
051776944
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
(1) Field of the Invention
THIS INVENTION relates to a method of, and apparatus for, computerised colour matching.
(2) Prior Art
Colour matching is a major problem in many industries, including automobile repair; paint and dye manufacture; printing; and fabric dyeing.
Tooth colour matching is a major problem for dentists and dental technicians when preparing dental caps, crowns or bridge work. They must seek to match the cap, or teeth on the bridge, to the surrounding natural teeth. At present the method is subjective and the results very much dependent on the skills of the person doing the colour matching.
The dental technician is supplied with a "colour map" of the tooth by the prescribing dentist or the map may be drawn by the dental technician, the map being made by comparison with standard porcelain chips. From that "colour map", the technician must build the dental caps/or prosthetic teeth being aware of the following problems:
(a) the dentist and the technician are most likely to have different colour perceptions of the colours under a standard reference light, let alone under different lights;
(b) there are variations in the colour of the porcelain powders as supplied by the various manufacturers against standard "shades" (or coded colours);
(c) some of the standard shades are very similar and therefore difficult to separate by eye;
(d) the depth of the dentine layer (or its translucency) affects the final colour; and
(e) the moisture content of the porcelain mix, the mix density, the firing frequency and temperature and the permeation of oxides through the opaque layer all affect the final colour.
Because of all these problems, colour mismatches may occur 10+% of the time.
In an effort to reduce the problem, a colour mixture indicator device as disclosed in U.S. Pat. No. 4,657,399 (Neil R. Hall) was developed where colour samples were provided in an array where the selected colour is either one of the samples or a mixture of the colour of two adjacent samples.
While this indicator is an improvement over the conventional porcelain colour chips, colour mismatches still occur.
SUMMARY OF THE PRESENT INVENTION
It is an object of the present invention to overcome, or at least minimize, the colour mismatches which can occur.
It is a preferred object to provide a method which can incorporate compensation factors to relate all colours against set standards.
It is a further preferred object to provide a method where the colours are measured against, colour corrected, even, constant light.
It is a still further preferred object to provide a method where the colours are measured in computer processable form, enabling a "colour corrected" map to be generated.
It is a still further preferred object to provide a suitable light source for effecting the method.
Other preferred objects of the present invention will become apparent from the following description.
In one aspect the present invention resides in a method of computerised colour matching of a first article with one or more other articles with which it is, or is to be, associated, the method including the steps of:
placing a reference set of colours adjacent the associated articles;
taking a photograph of the associated articles and the reference set of colours;
analysing the data from the photograph; and
generating a colour map and/or computer enhanced photograph of the associated articles using a computer, the colour map and/or enhanced photograph identifying the colour(s) of the associated articles relative to an absolute set of colours.
Preferably the computer compares the reference set of colours against the absolute reference set of colours to determine the compensation factor required to bring the reference set of colours into conformity with the absolute reference set, and applies this compensation factor to the colours of the associated articles (as photographed) to produce a corrected picture.
A specific analysis area of the corrected picture may be computer enhanced and the resultant enhanced picture may be prin
REFERENCES:
patent: 4422759 (1983-12-01), Holman et al.
patent: 4654794 (1987-03-01), O'Brien
patent: 4813000 (1989-05-01), Wyman et al.
patent: 4836674 (1989-06-01), Lequime et al.
patent: 4967379 (1990-10-01), Ott
Cartwright Iain
Graham Martin A. S.
Brown Laurence R.
Garibaldi Pty Ltd.
Lall Parshotam S.
Zanelli Michael
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