A comparison of thermal camera technology in diabetic foot complications

Abstract

Aim: The aim of the study was to compare temperature readings from low-cost thermal cameras to a higher quality thermal camera in order to determine whether these cameras could be safely utilised when obtaining such temperatures in the diabetic foot in a clinical setting. Research Design and Method: This research project was a quantitative, postpositivist and quasi-experimental study which investigated the ability of low-cost thermal cameras to report temperature readings which are comparable to those of a high-cost thermal camera. The higher cost, ‘gold standard’ thermal camera was the FLIR T630, while the two low-cost thermal cameras used were one stand-alone thermal camera, the FLIR C3, and one smartphone-attached thermal camera, the FLIR One Gen 1. A thermal image of each participant was taken with each camera at three different ambient temperatures of 19℃, 23℃ and 28℃, in order to investigate whether the surrounding ambient temperature could affect the ability of those low-cost thermal cameras to report the appropriate temperature readings. From each thermal image, 8 different toe and forefoot regions of interest were manually demarcated using the FLIR ResearchIR programme, which then provided the mean temperature of each region. The mean temperature scores of the low-cost thermal cameras were then compared to the mean temperature scores of the FLIR T630 camera through the appropriate statistical analysis. Results: The findings of this study showed that the FLIR C3 camera did not report comparable results to the FLIR T630 (p=<0.05) at 19℃ and 23℃, however, the temperature readings were statistically similar at 28℃. The FLIR One camera on the other hand reported statistically similar readings (p>0.05) in all three room temperatures, which contrasts to what was observed in the FLIR C3. From the FLIR One temperature readings, only the 5th digit readings at 19℃ varied significantly from the FLIR T630. Conclusion These findings in the present study indicate that while the FLIR One smartphone thermal camera was able to report similar temperature readings to the FLIR T630, the FLIR C3 was not, even though the FLIR One is a cheaper option than the FLIR C3. A possible explanation for this observation is that although the FLIR C3 has a higher cost, its infrared resolution is lower than that of the FLIR One. This could be due to the fact that since the FLIR C3 is a stand-alone thermal camera, it requires a lot of computational features and specifications that the FLIR One camera does not need since it uses the features of the smartphone device to which it is attached. This helps keeps the cost of the FLIR One camera very low, and since the only major feature of the FLIR One is the infrared sensor, an improvement in the sensor still allows the cost of the FLIR One to remain low. This study has shown that certain low-cost thermal cameras may be used to report temperature readings correctly, however, it is important that the thermal camera is tested and validated before it is used for detailed temperature reading analysis of the diabetic foot.