Colorectal cancer remains one of the leading causes of cancer mortality. Colonoscopy is the clinical gold standard for detecting and removing precancerous polyps because it provides direct visualization of the colonic mucosa. Nevertheless, the field of view is limited and the colon’s geometry is complex, so relevant areas can remain unobserved during routine inspection. This thesis introduces a pipeline that reconstructs a three-dimensional model of the inner colonic surface from monocular endoscopic video, with the aim of measuring where and how much mucosa was not seen. The method fuses RGB frames, predicted depth, and estimated camera pose through a TSDF-based reconstruction module to produce dense, anatomically faithful meshes.