The use of RGB-tracking of color changes during indigo-reduction processes based on LabVIEW machine vision

The use of an RGB-tracking chart for monitoring the reduction of indigo (color changes) based on the LabVIEW machine vision is demonstrated for the first time. In contrast to a normal analytical chromatographic chart, the time scale is used on the X-axis, but the sum of “RGB-pixels” is used on the Y-axis, instead of “signal intensity”. The RGB-tracking chart was obtained from an investigation of the process involved in the reduction of indigo, in which a PC camera was used as a detector and LabVIEW machine vision was simultaneously operated. As a result, when sodium dithionite (Na₂S₂O₄) and yeast were used, respectively, during the indigo-reduction processes, two types of reduction processes were found; the optimized timing for dyeing can be easily determined from the RGB-tracking charts. Furthermore, based on the changes in HSV (hue, saturation, lightness), the use of sodium dithionite provides a higher number of hue and saturation when clothes & fabric were dyed. In contrast to this, a longer time was required for the yeast solution to reach the same high number for hue and saturation. After comparing several series of dyed fabrics, we found that the use of an RGB-tracking chart is indeed a reliable novel tool for measuring color changes that occur during the chemical reactions that are associated with this process. Graphical abstract: [Figure not available: see fulltext.]