Authors:
Taiki Yano
1
;
Nobutaka Kimura
2
and
Kiyoto Ito
1
Affiliations:
1
Research & Development Group, Hitachi, Ltd., Kokubunji, Tokyo, Japan
;
2
Research & Development Division, Hitachi America, Holland, Michigan, U.S.A.
Keyword(s):
Object Recognition, 6DoF Pose Estimation, Depalletizing, Shrink-Wrapped Item.
Abstract:
We developed an object-recognition method that enables six degrees of freedom (6DoF) pose and size estimation of shrink-wrapped items for use with a mixed depalletizing robot. Shrink-wrapped items consist of multiple products wrapped in transparent plastic wrap, the boundaries of which are unclear, making it difficult to identify the area of a single item to be picked. To solve this problem, we propose a surface-graph-based 6DoF object-pose estimation method. This method constructs a surface graph representing the connection of products by using their surfaces as graph nodes and determines the boundary of each shrink-wrapped item by detecting the homogeneity of the edge length, which corresponds to the distance between the centers of the products. We also developed a recognition-process flow that can be applied to various objects by appropriately switching between conventional box-shape object recognition and shrink-wrapped object recognition. We conducted an experiment to evaluation
the proposed method, and the results indicate that the proposed method can achieve an average recognition rate of more than 90%, which is higher than that with a conventional object-recognition method in a depalletizing work environment that includes shrink-wrapped items.
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