This research work is part of the STANDUP project http://www.standupproject.eu/ dedicated to improve diabetic foot ulcer prevention and treatment of the plantar foot surface using smartphone-embedded thermal imaging system. The aim of this preliminary work is to build an ulcer assessment tool based on a smartphone and an IR thermal camera. The proposed system represents a practical tool for accurate DFU healing assessment, combining color and thermal information in a single user-friendly system. To ensure robust tissue identification, an annotation software was developed based on SLIC superpixel segmentation algorithm. The tool thus developed allows clinicians to achieve objective and accurate tissue identification and annotation. The proposed system could serve as an intelligent telemedicine system to be deployed by clinicians at hospitals and healthcare centers for more accurate diagnosis of diabetic foot ulcers.