Non-destructive testing of tea fermentation using image processing

Tea colour determination during fermentation is a vital problem in the tea industries. Experts have been traditionally measuring change of colour during fermentation by picking up some amount and observing the colour by eye approximation. Methods are also available for analysing the formation of colour constituents during fermentation. Another method uses colorimeter for determining the colour during fermentation. These methods are invasive and rely on frequent touching, contacting and collecting samples for chemical analysis. They destroy the quality and quantity of tea, disturb the environment created for fermentation in the fermenting room and make the measurement unhygienic. A non-destructive imaging technique has been developed, which is able to monitor the colour of the tea during fermentation with the help of a digital camera. The paper describes the imaging set-up, colour matching algorithm and comparison of the results with conventional manual methods.