Implementation of a pedobarographic system through effective crosstalk suppression with an all programmable system on chip

Abstract

Diabetes Mellitus which is characterized by longstanding hyperglycemia, promote diabetic peripheral neuropathy (DPN) and peripheral artery diseases (PAD) which invoke ulcerations especially on the foot plantar ultimately leads to amputations related morbidity and mortality. Recent clinical studies have identified distinct associations between DPN and foot plantar pressure, and PAD and foot plantar temperature. Hence, development of technology to analyze foot plantar pressure (pedobarography) and foot plantar temperature (pedothermography) to infer DPN and PAD associated diseases at the onset have recently stirred a significant interest among the scientific community. In the present study, we have primarily investigated the possibility of implementing a highly accurate large piezoresistive platform sensor array (a pedobrographic system) with an improved readout mechanism. We devised a readout circuit to mitigate inherent crosstalk interference with an improved scanning architecture implemented using a decoder-transistor based row driving electrodes and related electronics compatible with high frequency sensing. Then, the developed readout circuit was extensively validated and the proposed implementation was able to make measurements of significant accuracy with errors < 1% while not compromising the shape accuracy of the measured object. Initiatives were also taken to improve the data acquisition rate despite massive sensor data influx from 30,000 sensels. A Xilinx Zynq APSoC based data acquisition system was implemented to scan the entire array with 30,000 sensels and the analysis showed that the system demonstrated expected behavior. Overall, the proposed implementation entertained both static and dynamic pressure measurements of a foot plantar. A subsequent static calibration of the piezoresisitive sensor array was conducted using weight plates and the calibrated sensor array was validated against an existing commercial plantar pressure measurement system to determine its performance. In addition, possibility of implementing a screening tool for pedothermographic assessment using near infrared (NIR) technology was investigated to provide an overall assessment of both foot planters in a single frame and record both regional and point temperatures of the foot plantar. The proposed thermal imaging system is anticipated to be used in routine clinical assessment of diabetic foot complications at diabetic clinics to provide improved diagnostics, thereby contributing to prevention of diabetic foot ulcerations, amputations and related morbidity.