## 2 Materials and Methods
### Methodological Framework  
#### 2.2.1 Capture of the Clinical Dataset  
The study was conducted at the Diabetic Foot Unit from Universidad Complutense de Madrid, in Spain, following the approved study protocol. This protocol was approved by a local institutional review board (Clinical Research Ethics Committee--CEIM Clinic Hospital Clinico of San Carlos, Ref No: 24/007-E). The Diabetic Foot Unit from Universidad Complutense de Madrid took on the process of collecting written consent for all patients included in this study. Thermographic images were first captured from the patients participating in the study. The sample consisted of a total of 147 patients, generating 147 images in total, corresponding to one image per feet for each participant (see Figure 1). Figure 1: Examples of captured thermographic images. The patients selected for the study met the following criteria:  
* Adults, without distinction of sex. * Diagnosed with type 1 or type 2 diabetes mellitus, regardless of pharmacological treatment received. * No exposure to extreme temperatures for at least three days prior to the consultation. * No intense physical activity was performed in the 24 h period before image acquisition. Patients were excluded from the study if they presented any of the following conditions:
* Active foot ulcers. * Neuropathy of non-diabetic origin. * Lower limb revascularization performed within the past four weeks. * Inability to capture thermographic images due to anatomical characteristics. * Cognitive impairments that hindered participation in the study. * Explicit refusal to participate in the study. * Major amputations of either foot. The patients included in the study were previously diagnosed by clinical specialists. To this end, these patients underwent a standardized neurological screening (including Semmes-Weinstein monofilament testing, tuning fork examination, and NerveCheck Master(r); Phi Med Europe SL, Barcelona, Espana) and a vascular assessment (palpation of distal foot pulses, ankle-brachial index [ABI], toe-brachial index [TBI], and transcutaneous oxygen pressure [TcPO2]). This allowed for the determination of whether the study participants were specifically affected by diabetic neuropathy and/or peripheral arterial disease. Based on these evaluations, they were categorized into two groups: patients with DPN and/or PAD (non-healthy patients) and patients without these conditions (healthy patients). Based on that, a detailed distribution of participants is presented in Table 1.  
Prior to the acquisition of thermographic images of both feet, the environmental conditions of the room were verified. The temperature was maintained at 25 \({}^{\circ}\)C (\(\pm\)1 \({}^{\circ}\)C), with a relative humidity of 55% [11]. These conditions were controlled to ensure the reproducibility of the thermographic measurements. Participants were instructed to remove their shoes and socks and to cleanse their feet using a damp towel. After that, to take the picture, each patient was positioned supine on an examination table for a minimum of 15 min. Based on our experience and prior experimental evidence [11], this period allowed for thermal equilibrium in the plantar region, minimizing variability and ensuring reliable temperature acquisition. To ensure thermal isolation and preserve patient privacy, a blue cloth with specific openings was used to expose only the soles of the feet. This method minimized thermal interference from the rest of the body and maintained subject confidentiality. Thermographic images were captured using a Thermal Expert TE-Q1 camera (i3 System Inc., Daejeon, Republic of Korea), which has a good performance for e-health applications [12]. This device was chosen for its high thermal sensitivity and precision, essential features for clinical evaluation. The acquired images were processed to automatically segment the soles of the feet and to dynamically adjust the thermal scale according to the maximum and minimum