The early detection of diabetic ulcers using thermal imaging is an important aspect of non-invasive medical instrumentation. An accurate assessment of a diabetic foot ulcer (DFU) using a machine-based approach requires a crystal-clear region of interest (ROI) of the foot ulcer. Different shapes based on automatic contour determination after the segmentation procedure can act as a major guide for the purpose of appropriate localization of the ROI. The purpose of this paper is to present a novel shape-area-based analysis for precisely localizing the ROI from the patient’s foot. The novel data set, which is suitable for Indian healthcare settings, was created at PGIMER hospital Chandigarh with the support of specialized clinicians. A comparison of various cutting-edge segmentation techniques was carried out. The quantitative analysis concluded that the average area (AA) of ROI, derived from different shapes, was extremely close to the ground truth values and thus offered a better prospective to automatically examine the ulcer area.