Measurement parameter of color on yacon (Smallanthus sonchifolius) slices using a computer vision system

The aim of this research was to design, implement and calibrate a Computer Vision System (CVS), for use in real-time, in order to measure the color on minimally processed yacon slices. For this purpose, a device (software and hardware) was designed and implemented which consisted of two steps: a) image acquisition and b) image processing and analysis. For both, an algorithm and a graphical user interface (GUI) were developed in MatLab. CVS calibration was performed with a conventional colorimeter (Model CIE L*a*b*). Minimally processed yacon slices were obtained and stored at 5 degrees C. Color changes were estimated every 2 h, for 26 h, obtaining its color parameters. L* decreased from 65.9 to 60.8, with a tendency to a black color; a* increased from 7.3 to 17.7, approaching a red color; b* increased from 35.1 to 41.5, presenting a tendency to a yellow color. Moreover, C* increased from 35.9 to 40.1, H* decreased from 78.2 to 66.9 and Delta E* increased from 2.6 to 13.2. Low errors calculated (e(L*) = 5.001%, and e(a*) = 2.287%, and e(b*) = 4.314%) ensure suitable and efficient application in industrial process automation and quality control in the food industry. (C) 2014 Elsevier Ltd. All rights reserved.