US 9,811,733 B2
Method, apparatus and system for selecting a frame
Ka Ming Leung, Marsfield (AU)
Assigned to Canon Kabushiki Kaisha, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Oct. 2, 2014, as Appl. No. 14/505,364.
Claims priority of application No. 2013237718 (AU), filed on Oct. 4, 2013.
Prior Publication US 2015/0098645 A1, Apr. 9, 2015
Int. Cl. G06K 9/00 (2006.01); G06F 17/30 (2006.01); G06T 7/55 (2017.01)
CPC G06K 9/00664 (2013.01) [G06F 17/30811 (2013.01); G06T 7/55 (2017.01)] 19 Claims
OG exemplary drawing
 
1. A non-transitory computer-readable medium storing instructions that, when executed by a processor, implement a method of selecting a pair of keyframes from a plurality of video frames captured by a camera, said method comprising: determining features of a candidate frame to which predetermined map points in a three dimensional space are projected; creating a histogram of the determined features for a plurality of regions in the candidate frame; determining one of the regions as being an unmapped region based on the created histogram; selecting the candidate frame as a new keyframe based on a size of the unmapped region; and selecting a previous keyframe to pair with the new keyframe based on a density of features in the unmapped region and a determined size between the previous keyframe and the new keyframe to produce a 3D map of point features.