Monitoring of dry powder mixing with real-time image processing

The aim of this study was to develop and evaluate a PC-based continuous image processing technique to monitor binary dry powder mixing homogeneity in real-time. Gray scale images of the binary powder mixture during mixing were captured with a low-cost CMOS camera. The pixel value with the maximum number of occurrences for each image at every scan interval during mixing was determined and observed over time with a computer program developed in G-programming language. The time when the maximum number of occurrences over time stayed constant was considered to be the equilibrium state for the mixture. The equilibrium times were 12.5, 13.9 and 13.6 min for 10 kg plaster and 20, 40 and 60 g black dye mixtures and 10, 14.7 and 26 min for 10 kg plaster and 20, 40 and 60 g red dye mixtures, respectively. The test results showed that the system can be used to monitor the degree of mixing homogeneity of binary powders in real-time. © 2007 Asian Network for Scientific Information.