@TechReport{Muenzer2012, author = {Münzer, Bernd and Schoeffmann, Klaus and Böszörmenyi, Laszlo}, institution = {Institute of Information Technology ({ITEC}), Klagenfurt University}, title = {Detection of Circular Content Area in Endoscopic Videos for Efficient Encoding and Improved Content Analysis}, year = {2012}, address = {Klagenfurt, Austria}, month = {nov}, number = {TR/ITEC/12/2.03}, abstract = {The actual content of endoscopic videos is typically limited to a circular area in the center of the image due to the inherent characteristics of the camera. This area is surrounded by a dark border that fills up the remainder of the rectangular image and is subject to noise. The position and size of the circle is not standardized and usually varies over time. In this paper a robust algorithm is presented that (1) classifies which parts of an endoscopic video feature a circular content area and (2) determines its exact position and size, if present. This information is useful for improving video encoding efficiency, limiting further analysis steps to the relevant area and saving ink when printing still images on findings. Our evaluation shows that the proposed method is very fast, reliable and robust. Moreover, it indicates that by exploiting this information for video encoding a considerable bitrate reduction is possible with the same visual quality.}, language = {EN}, pages = {20}, pdf = {https://www.itec.aau.at/bib/files/CircleDetection.pdf} }