Classification and quantitative optical analysis of liquid and solid samples using a mobile phone as illumination source and detector

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• 作者：Zafar Iqbal ; Mats Eriksson
• 关键词：Mobile phone ; Optical sensor ; Beer&ndash ; Lambert law ; Absorption ; Colorants
• 刊名：Sensors and Actuators B: Chemical
• 出版年：2013
• 出版时间：August, 2013
• 年：2013
• 卷：185
• 期：Complete
• 页码：354-362
• 全文大小：1086 K

文摘

A mobile phone has been used both as illumination source and image detector for quantitative optical analysis of colored liquid samples (4 different colorants) and solid samples (printed color patterns, plastic beads and colored sand grains). Even though the measurement conditions were far from ideal, because the light source was strongly polychromatic and the illumination was not a collimated light beam with homogeneous light intensity, a logarithmic concentration dependence, in accordance with the Beer-Lambert law, described the data of the colored liquids quite well. By utilizing blue-blue (420-510 nm), green-green (480-590 nm) and red-red (575-695 nm) illumination/detection combinations, each sample could be assigned a unique color signature for classification that agreed with reference absorbance spectra measured with a spectrometer. Quantification of validation samples within a few percent of the actual values was achieved. Also the long-term repeatability of the measurements was investigated and was surprisingly good for such a simple system. Analysis of the colored solid samples was more complex with results being dependent on the morphology and colorimetric properties of the samples.