Deep Object Ranking for Template Matching

Abstract

Pick-and-place is an important task in robotic manipulation. In industry, template-matching approaches are often used to provide the level of precision required to locate an object to be picked. However, if a robotic workstation is to handle numerous objects, brute-force template-matching becomes expensive, and is subject to notoriously hard-to-tune thresholds. In this paper, we explore the use of Deep Learning methods to speed up traditional methods such as template matching. In particular, we employed a Single Shot Detection (SSD) and a Residual Network (ResNet) for object detection and classification. Classification scores allows the re-ranking of objects so that template matching is performed in order of likelihood. Tests on a dataset containing 10 industrial objects demonstrated the validity of our approach, by getting an average ranking of 1.37 for the object of interest. Moreover, we tested our approach on the standard Pose dataset which contains 15 objects and got an average ranking of 1.99. Because SSD and ResNet operates essentially in constant time in a Graphics Processor Unit, our approach is able to reach near-constant time execution. We also compared the F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> scores of LINE-2D, a state-of-the-art template matching method, using different strategies (including our own) and the results show that our method is competitive to a brute-force template matching approach. Coupled with near-constant time execution, it therefore opens up the possibility for performing template matching for databases containing hundreds of objects.