STBD: a simple tri-bit binary descriptor for point matching

This study investigates the problem of constructing binary descriptor and develops a novel binary descriptor called simple tri-bit binary descriptor (STBD) based on a simple sampling pattern (SSP) and a tri-value binarisation strategy (TBS). First, an SSP is proposed, in which sample points are divided into two groups according to the distance from the pattern centre and smoothed by different circular filters. Then, to make the descriptor adaptive to the matched images, a selection strategy which directly employs detected keypoints as training data is introduced to select 256 point pairs with low correlation from initial pairs. Finally, a modified TBS method is presented to properly refine intensity comparison results. Experiments show that the proposed STBD can perform well and is robust to various transformations, except for scale change.