A method of detecting an edge of a support surface by an imaging controller includes: obtaining a plurality of depth measurements captured by a depth sensor and corresponding to an area containing the support surface; selecting, by the imaging controller, a candidate set of the depth measurements; fitting, by the imaging controller, a guide element to the candidate set of depth measurements; and detecting, by the imaging controller, an output set of the depth measurements corresponding to the edge from the candidate set of depth measurements according to a proximity between each candidate depth measurement and the guide element.