Apparatus and methods are described for use with an endoluminal data-acquisition device configured to acquire endoluminal data points while moving through a lumen of a subjects body generally in a first direction with respect to the lumen. While the endoluminal data-acquisition device is being moved through the lumen, a plurality of endoluminal data points of the lumen are acquired using the endoluminal data-acquisition device. It is determined that, at least one location, two or more endoluminal data points were acquired. An output is generated using a portion of the plurality of endoluminal data points of the lumen acquired using the endoluminal data-acquisition device, by using only a single endoluminal data point corresponding to the location. Other applications are also described.