Skin image mosaicing with topological inference and global adjustment

Teledermatology offers several advantages in comparison to the traditional in-place consultations with a dermatologist. It is particularly useful for easing the access to the dermatological care for patients with mobility or travel constraints. A dedicated mosaicing scheme for creating extended panoramas of skin video sequences is proposed to surmount the limitations posed by the small field of view of stationary images acquired by currently used devices. The video sequences used for this purpose are acquired using a specially designed device for a colorimetrically correct rendering of the skin surface. After a study of various image registration approaches, an approach optimally suited to skin image registration with some compromise between registration accuracy and computation time is selected. In addition, an approach for refining the initially detected key-point correspondence is presented. Central focus of this study is on the overall coherent construction of the mosaic. To achieve this objective, a mosaicing scheme capable of generating coherent panoramas from long video sequences is presented. This scheme dynamically estimates the topology of the image trajectory in the panoramic plane to mosaic the images by reducing the number of images over the path used for reaching a given image from a reference image in order to place it on the panoramic plane. A small number of images reduces the accumulated errors, thus improving the visual coherency of the overall mosaic. Besides, the proposed approach offers robustness against failed registrations, which would interrupt the mosaicing process in the absence of the alternative paths. Moreover, a global adjustment scheme for further improving the coherency of the mosaic is presented