Automatic Range Adjustment of the Fluorescence Immunochromatographic Assay Based on Image Processing
College of Physics and Information Engineering, Fuzhou University, Fuzhou 350108, China
Key Lab of Medical Instrumentation & Pharmaceutical Technology of Fujian Province, Fuzhou 350108, China
Key Lab of Eco-Industrial Green Technology of Fujian Province, Nanping 354300, China
State Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, Macau 999078, Macau SAR, China
Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macao 999078, China
Author to whom correspondence should be addressed.
Sensors 2020, 20(1), 209; https://doi.org/10.3390/s20010209
Received: 29 November 2019 / Revised: 20 December 2019 / Accepted: 25 December 2019 / Published: 30 December 2019
(This article belongs to the Special Issue Point-of-Care Sensing Devices)
As an emerging technology, fluorescence immunochromatographic assay (FICA) has the advantages of high sensitivity, strong stability and specificity, which is widely used in the fields of medical testing, food safety and environmental monitoring. The FICA reader based on image processing meets the needs of point-of-care testing because of its simple operation, portability and fast detection speed. However, the image gray level of common image sensors limits the detection range of the FICA reader, and high-precision image sensors are expensive, which is not conducive to the popularization of the instrument. In this paper, FICA strips’ image was collected using a common complementary metal oxide semiconductor (CMOS) image sensor and a range adjustment mechanism was established to automatically adjust the exposure time of the CMOS image sensor to achieve the effect of range expansion. The detection sensitivity showed a onefold increase, and the upper detection limit showed a twofold increase after the proposed method was implemented. In addition, in the experiments of linearity and accuracy, the fitting degree (R2) of the fitted curves both reached 0.999. Therefore, the automatic range adjustment method can obviously improve the detection range of the FICA reader based on image processing.