Using the Infocus-Breakpoint to estimate the scale of neoplasia in colonoscopy

Colonoscopy is the reference medical examination for early diagnosis and treatment of colonic diseases. This minimally invasive technique allows gastroenterologists to explore the colon and remove neoplasias - abnormal growth of tissue - such as polyps which may transform into malignant tumors. Shape, texture and size of polyps are of particular interest for determining their nature. However, the size of neoplasias is difficult to estimate because the absolute scale of the observed tissue is not directly conveyed in the 2D endoscopic images. We here improve our Infocus-Breakpoint (IB) technique, which estimates an imagewise scale by detecting the blur/ unblur breakpoint in a video sequence. We simultaneously track a neoplasia with a 2D affine transformation and estimate the amount of defocus blur. This leads to an areawise scale estimate with better accuracy.