<title>Imaging tristimulus colorimeter for the evaluation of color in printed textiles</title>

Abstract

The high-speed production of textiles with complicated printed patterns presents a difficult problem for a colormethc measurement system. Accurate assessment of product quality requires a repeatable measurement using a standard color space, such as CIELAB, and the use of a perceptually based color difference formula, e.g.color difference formula.Image based color sensors used for on-line measurement are not colormetric by nature and require a non-linear transformation of the component colors based on the spectral properties of the incident illumination, imaging sensor, and the actual textile color. This research and development effort describes a benchtop, proof-of-principle system that implements a projection onto convex sets (POCS) algorithm for mapping component color measurements to standard thstimulus values and incorporates structural and color based segmentation for improved precision and accuracy. The POCS algorithm consists of determining the closed convex sets that describe the constraints on the reconstruction of the true tristimulus values based on the measured imperfect values. We show that using a simulated D65 standard illuminant, commercial filters and a CCD camera, accurate (under perceptibility limits) per-region based values can be measured on real textile samples.

Color Sensors and Their Applications

“…In this latter case, however, employing a colorimeter may no longer be a viable option for real-time monitoring and other solutions had to be found. Such a solution used machine vision and image processing for large-area continuous textile process monitoring [55].…”

Preliminary study of vision system for the colorfastness rate assessment on woven fabrics

“…This method is conducted by a manual-direct comparison between the fabric's colors with the gray scale standard. Hence this method considered as an inaccurate, susceptible for any bias yet time consuming [3][4] [6]. Alternatively, the objective method is needed to improve the accuracy on the quality assessment process.…”

“…Principally, the colorfastness rate can be determined with a digital image processing method of the fabric samples which conducted by comparing both of observed (outdated) and reference fabric's colors which stated on the CIELAB color coordinate system [3] [7]), CIE94 ( [11]) and CIEDE2000 ( [9]). This color different formula will be continually executed until the proportional color difference value that adequate to the human visual perception obtained.…”