Image Processing Method to Estimate Water Quality Parameter

Abstract

Human settlements in rural areas face multiple sanitary challenges including water quality, the control of which is usually deemed as secondary due to the lack of materials or appropriate equipment. Hence, the measurement of water quality parameters, including the concentration of free chlorine, is extremely important. This paper proposes a sensing system for the measurement of free chlorine concentration based on the traditional colorimetric method, with N,N-diethyl-p-phenylenediamine as the reagent. The major hardware components are a dark room and a stationary digital camera. Using the proposed image processing method, the algorithm quantifies the pigmentation change and subsequently estimates the free chlorine concentration of the sample. Following this, a regression model is derived from the compiled data, which enables the evaluation of new samples in terms of free chlorine concentration. This model has an estimation error of less than 7% and a working range of 0.26 ppm to 1.50 ppm.