*2.1.1 Thermal camera specifications*

Most of the work in plantar foot thermography has been done on thermograms acquired using an infrared thermal imaging camera. Thermal imaging cameras with a high resolution made suitable for medical applications can measure subtle temperature changes and hence are capable of improved detection of diabetic foot complications. A FLIR E60 thermal imaging camera is used for the present study to acquire plantar foot thermal images. It has a resolution of 320x240 pixels and covers a Field of View (FOV) of 25°x19°. The range of operation of the camera is in the region of the infrared spectrum from 7.5 μm to 13 μm wavelength. It can detect the temperature in the range of 20–650°C with thermal sensitivity of less than 0.05°C at 30°C and has an onboard digital camera with a resolution of 3.1 megapixels (MP). The onboard digital camera covers the same FOV as that of the thermal imaging camera and acquired images are of size 2048x1536 pixels. The temperature values are associated with a color palette (Rainbow Color Scheme palette) to represent and distinguish them graphically, where blue and green shades represent cooler regions. Warmer regions are represented by yellow, orange, and red colors in the increasing order of temperature respectively. Maximum temperature (intensity) is represented in white.

**Figure 1.** *Statistical analysis-based system for detection of diabetic foot.*

It is ensured that the thermal imaging camera is calibrated against a black body reference as per the manufacturer's recommendations [14].
