Use of Contrast of Digital Photo Images for the Determination of the Turbidity of Liquids

Resumo

A possibility of using a digital camera and the subsequent computer processing of chromaticity characteristics of a photo image for the determination of the turbidity of liquids is studied on examples of measurements of the transparency of technical sulfuric acid and the determination of the kaolin turbidity of water. Measurements were performed on a modified Jackson turbidimeter. It was shown that, in the RGB space, the contrast of a photo image of an alignment template is a chromaticity characteristic suitable for measuring turbidity. The interference of the yellow color of suspensions in measurements of turbidity was eliminated in the green channel. A correlation equation was found for the contrast (degree of turbidity) and concentration of the suspension. The equation does not differ from that of the law of light absorption. Performance characteristics of the determination of the kaolin turbidity of water were estimated in comparison with those of conventional turbidimetry. It was shown that, despite the primitiveness of the instrumentation for the proposed method of photographic turbidimetry, its characteristics are not inferior to those of classical turbidimetry.