TransHist: Occlusion-robust shape detection in cluttered images

Abstract

Shape matching plays an important role in various computer vision and graphics applications such as shape retrieval, object detection, image editing, image retrieval, etc. However, detecting shapes in cluttered images is still quite challenging due to the incomplete edges and changing perspective. In this paper, we propose a novel approach that can efficiently identify a queried shape in a cluttered image. The core idea is to acquire the transformation from the queried shape to the cluttered image by summarising all pointto-point transformations between the queried shape and the image. To do so, we adopt a point-based shape descriptor, the pyramid of arc-length descriptor (PAD), to identify point pairs between the queried shape and the image having similar local shapes. We further calculate the transformations between the identified point pairs based on PAD. Finally, we summarise all transformations in a 4D transformation histogram and search for the main cluster. Our method can handle both closed shapes and open curves, and is resistant to partial occlusions. Experiments show that our method can robustly detect shapes in images in the presence of partial occlusions, fragile edges, and cluttered backgrounds.

Manufacturable pattern collage along a boundary

“…Kwan et al [7] proposed a bottom-up solution to generate collages with arbitrary and irregular shapes in a scale-invariant domain, using a scaleinvariant shape descriptor called PAD. They further adopted this descriptor to identify a queried shape in a cluttered image [11]. Saputra et al [12] presented a technique for drawing ornamental designs consisting of simple elements that are carefully arranged and deformed to conform to a user-specified flow.…”