libLDB: A Library for Extracting Ultrafast and Distinctive Binary Feature Description

LDB (Local Difference Binary) is a highly efficient, robust and distinctive binary descriptor. The distinctiveness and robustness of LDB are achieved through 3 steps. First, LDB captures the internal patterns of each image patch through a set of binary tests, each of which compares the average intensity Iavg and first-order gradients, dx and dy, of a pair of image grids within the patch (Fig1. (a) and (b)). Second, LDB employs a multiple gridding strategy to capture the structure at different spatial granularities (Fig1. (c)). Coarse-level grids can cancel out high-frequency noise while fine-level grids can capture detailed local patterns, thus enhancing distinctiveness. Third, LDB selects a subset of highly-variant and distinctive bits and concatenates them to form a compact and unique LDB descriptor. Fig.1 illustrates the key idea of LDB feature extraction.

Fig. 1 Illustration of Key Idea of LDB Feature Extraction.

Fig. 2 LDB is invariant to object rotation.


X. Yang, C. Huang and K. -T. Cheng, "libLDB: A Library for Extracting Ultrafast and Distinctive Binary Feature Description," in ACM International Conference on Multimedia (ACMMM),Open Source Software Competition, 2014.