Technical Characterization of a Low-Cost Thermal Imaging System for Future Diabetic Foot Assessment

A diabetic foot is a serious complication of Diabetes Mellitus (DM) and a leading cause of non-traumatic lower-limb amputations. Infrared thermography has been suggested as a low-cost, noninvasive tool for the early detection of thermal alterations associated with this condition. This study evaluates the performance of a thermal imaging system based on the FLIR Lepton 3.1R module through technical characterization under predefined acquisition conditions. A blackbody source was used as the thermal reference within a temperature range of 31 to 40 °C, and measurements were acquired at predefined distances. Thermal measurements obtained with the FLIR Lepton 3.1R were compared with those acquired using an FLIR C5 thermal camera, which was used as a comparison device in the experimental evaluation. The FLIR Lepton 3.1R measurements showed an average deviation of 1 to 2 °C relative to the blackbody reference values, indicating stable performance under the evaluated acquisition conditions. Overall, the results support the potential of the FLIR Lepton 3.1R module as a low-cost platform for the analysis of spatial thermal patterns, representing a preliminary step toward future clinical validation studies aimed at diabetic foot assessment.