Trichromatic Color Analyser

Trichromatic Color Analyser
Original author(s) Razvan Ion Preda, Pichayada Katemake
Developer(s) Thai Colour Science Research Unit
Development status on hold
Operating system Microsoft Windows (x86, x64)
Available in English
Type Computational Physics
License Proprietary[1]
Website trichromaticity.com

Trichromatic Color Analyser (TCA) is the name of a software package and of a software system. The software package contains tools that offer the possibility to set up flatbed scanners as tristimulus colorimetric devices, having the advantage over commercial colorimeters of measuring color on flexible sized areas (ranging from 0,07 sqmm to 100 sqcm) and of performing a list of colorimetric calculations that exploit this feature. TCA was developed in the Color Research and Multimedia Laboratory of the Department of Imaging and Printing Technologies in the Faculty of Science of Chulalongkorn University and is the first scientific software package ever released by this university.[2][3]

History

Software creation started within development of a method for analyzing, identifying and preserving traditional Thai colors used in Thai mural paintings.[4] A beta version of the software was presented at the 'Colours in Life' Symposium in Bangkok in January 2012.[5] The color correction methodology of the scanner's output for the software version used in analyzing and identifying the traditional Thai colors has been published in Color Research and Application Journal in the article "Complete Study of Traditional Thai Colors used in Mural Paintings: Traditional Thai Color Name Dictionary".[6] A system, containing the TCA software installed on a specially configured computer connected to an Epson GT20000 scanner, was created and later expanded for general use. The system, also called Trichromatic Color Analyser, has been tested in applications such as determining the color of ink written on paper (for forensic laboratories) and optimising the print pressure in offset printing of half-tones on coated and uncoated substrates.[2][3] The system was further adapted for the creation of a novel method for monitoring the developing of browning in fruit and fruit-juice.[7] Its use for automatic monitoring of apple browning for determining optimal inhibitor mixtures was orally presented at the 2nd International Conference on Agriculture and Agro-Industry in 2014.[8]

Description

TCA is described in three articles,[6][9][10] a description that can be summarized as follows.

The system was named 'Trichromatic Color Analyser' to reflect its basic function: trichromatic color analysis. Its main purpose is to turn a scanner into a colorimeter in order to use the scanner's glass as measurement port. Its main advantage is that it measures color samples on flexible sized areas, unlike dedicated colorimeters that are limited by their fixed aperture of the measurement port.
TCA's primary goal is to obtain accurate color information from scanner by defining a color space, named TCA colorspace, based on user's needs and system's limits, in which any color sample can be analyzed with the accuracy of a tristimulus colorimetric device. This approach is fundamentally different compared with color management software that has the objective of obtaining good matches across color devices connected to computers while sacrificing colorimetric accuracy in favour of offering pleasing images on these devices.
TCA was initially developed during the research for finding a reasonable solution to the problem of color-measurement on inhomogenous color-samples painted with traditional Thai colors. Encouraged by the fact that no scientific software was released in Chulalongkorn University until 2011, according to the university's IP office, the authors decided to create a fully functional software system that controls the scanner, overrides its factory settings and performs a variety of colorimetric calculations. Tools have been developed continuously according to the needs of several research projects in which TCA has been used, keeping the system in a perpetual beta version. The functions qualifying TCA for monitoring browning of fruits, for example, are given by its tools of automatically capturing images at given intervals, of calculating colorimetric values for all color positions contained in the captured images, of analyzing the color-homogeneity of the measured surface and of recording the color difference in an established time-frame over hours and days.

User Guide

Trichromatic Color Analyser has a user manual with 139 pages that combine both system documentation and user documentation. Printed in 2012, the manual has not been updated yet.[11] In order to use the Trichromatic Color Analyser, computer and scanner have to be configured in a 3-step calibration followed by procedures not entirely described in the user manual but added subsequently in published articles.[6][9][10] First steps are:
1. a primary rough calibration that involves the Munsell grey patches N2, N3.5, N5, N6.5, N8 and N9.5;
2. a secondary calibration using the 24 ColorChecker colors from which cyan is excluded;
3. a third calibration stage using 1300 Munsell mat patches.
Once the calibration sequences are concluded, TCA must be used to establish a color space (called TCA colorspace) based on an optimum balance between:
a) minimum mean color differences of scanned colors versus their spectrophotometric measured values (CIE L*a*b* D65/2°);
b) minimum mean standard deviation;
c) a maximum of Munsell colors captured within a color-tolerance value decided by the user.
The Trichromatic Color Analyser system designed as TCA LabPack System[12] does not need the above preparatory procedures in order to be used. Published functioning parameters for one of the TCA systems are: 2.39 deltaE2000 units for the mean color difference of the Color-Checker Colors versus their spectrophotometric values with a mean standard deviation of 0.8952 and 1140 Munsell colors, out of 1300, captured within a 4.4 deltaE2000 imposed color tolerance.[6] TCA system uses digitized values for Munsell, Resene, Crayola and NBS-ISCC colour dictionaries, as well as a NCS digitized color dictionary with restricted license,[13] for color-matching within the TCA colorspace.
There are 2 ways of scanning. One way is with TCA’s Location Calibrator (a physical grid used for placing samples on the scanner glas) and a software module developed for it. Another way is through a different software module that controls the scanner’s TWAIN interface. The Location Calibrator places the sample at a determined distance from the scanner-glass-edges and forces user to scan always in the same position, keeping consistency of measurements and eliminating part of the influence that image noise could have on TCA’s color correction algorithms. Samples are placed on the clean scanner glass with a pair of gloves to avoid the interference of fingerprints. TCA can be operated through voice commands and has built in voice user guides, so that gloves do not have to be removed when handling multiple scans.

Development and Distribution

Trichromatic Color Analyser is claimed to be the first distributable software that turns scanners into colorimeters.[14] The system has been in a perpetual beta version due to its continuous use within different projects that needed different types of adaptations and expansions of the system. The software system has been built as a commercial product to be distributed through the Faculty of Science of Chulalongkorn University. It is used in the Thai Color Science Research Unit, where it can be seen and tested.[15] Development has been put on hold and resumption is to be announced by the authors when research environment and collaboration conditions will allow it.[7]

About the authors

Dr. Eng. Razvan Ion Preda received a B.S. degree in Chemistry from the University Politechnica Bucharest, Romania in 1993 and a Ph.D. in applied physical chemistry in 1999. He is also certified Analyst Programmer. After working a short period in the National Institute for Research and Development in Informatics, Bucharest he led research projects in partnership with Computerland, Curtidos Mare Nostrum, National Research and Development Institute for Textiles and Leather, etc. and collaborated with several universities. His work has primarily focused on developing and improving methods and processes for the industrial sector. He created TCA while working as an expert in Chulalongkorn University and as a researcher under National Research Council of Thailand (Reg. No. 0157).[16]
Assoc. Prof. Dr. Pichayada Katemake received a B.S. degree in imaging and printing technology from Chulalongkorn University in 1993 and M.S. and Ph.D. degrees in color physics from University of Leeds, United Kingdom, in 1996 and 2001 respectively. She was a guest professor for Master CIMET course, University Jean Monnet, Saint Etienne, France. She is currently an associate professor in the Department of Imaging and Printing Technology and the Head of Colour Science Research Unit, Chulalongkorn University.[16]

References

  1. ↑ http://thaicolour.com/download/software_copyright.pdf
  2. 1 2 (2012), Thailand. AIC (Association International de la Couleur) Annual Report, 25, p31.
  3. 1 2 "AIC Annual Report" (PDF). International Colour Association. 2012-10-30. Retrieved 2015-10-29.
  4. ↑ Preda, R. I., Katemake, P., Pungrassamee, P. and Hoontrakul, D. (2011). Method for identifying, analyzing and preserving colors of Thai Mural Paintings, ICIPT 2011 Conference Proceedings, Bangkok, Thailand pp.15-18.
  5. ↑ Preda, R. I., Katemake, P. (2012). First final version of the Trichromatic Colour Analyser Software, Colours in Life 2011 Proceedings, Bangkok, Thailand pp.11-14.
  6. 1 2 3 4 Katemake, P. & Preda, R.I. (2014). Complete Study of Traditional Thai Colors Used in Mural Paintings: Traditional Thai Color Name Dictionary. Color Research and Application, 39 (6), pp616-629.
  7. 1 2 "Thai Colour Science Projects". Colour Science Research Unit. 2013-08-11. Retrieved 2015-10-29.
  8. ↑ "Oral presentation program: Automatic Monitoring Method of Apple Browning for Determining Optimal Inhibitor Mixtures" (PDF). Mae Fah Luang University. 2014-10-18. Retrieved 2015-10-29.
  9. 1 2 Katemake, P. and Preda, R. I. (2013). Bringing Traditional Thai Colours to Life using an Original Developed Software System, AIC2013 – 12th International AIC Congress, The SAGE, Gateshead 8–12 July 2013, pp1473-1476.
  10. 1 2 Katemake, P., Preda, R.I. and Duangmal, K., Automatic Monitoring Method of Apple Browning for Determining Optimal Inhibitor Mixtures. In the 2nd International Conference on Agriculture and Agro-Industry 2014 (ICAAI2014) Fresh Produce, Novel Process and Health Product, 20–21 November.
  11. ↑ Preda, R. I. and Katemake, P. (2011) Trichromatic Colour Analyser V 1.0.0.0.0 User's Manual. Interprint Supply (Thailand)
  12. ↑ "Trichromatic Color Analyser Product Page". Colour Science Research Unit. 2012-10-01. Retrieved 2015-10-29.
  13. ↑ "NCS license" (PDF). Thai Colour Science Research Unit. 2011-12-08. Retrieved 2015-10-29.
  14. ↑ "Trichromatic Color Analyser". Colour Science Research Unit. 2012-10-01. Retrieved 2015-10-29.
  15. ↑ "TCA LabPack". Colour Science Research Unit. 2012-10-01. Retrieved 2015-10-29.
  16. 1 2 (2014), About the authors. Color Research and Application, 39 (6), pp532-534.
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