Chiun-Hong Chien

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With the advent of devices that can directly sense and determine the coordinates of points in space, the goal of constructing and recognizing descriptors of three-dimensional (3-D) objects is attracting the attention of many researchers in the image processing community. Unfortunately, the time required to fully sense a range image is large relative to the(More)
This paper presents our work from an on going project on motion and pose estimation for supporting vision-guided fine manipulation of orbital replaceable units in a cluttered environment. The major challenges of this work include target objects, some with highly reflective or mirror surfaces, moving in a cluttered environment with changing illumination.(More)
Octrees have been extensively used for 3D object representation. The authors have previously developed a scheme, that exploits the volume intersection approach, to generate the octree of an object from three orthogonal views. In this paper, the scheme is extended to generate a “generalized octree” of an object from three known non-coplanar views. The block(More)
The Extravehicular Activity Helper/Retriever (EVAHR) is a free-flying robot currently being developed by the Automation and Robotics Division at the NASA Johnson Space Center to support activities in the neighborhood of Space Station Freedom or planetary habitat. The EVAHR's primary responsibilities are rescue of crew, and retrieval of critical equipment.(More)
In this paper, we present work from our ongoing project on vision-guided retrieval and insertion of ORUs. Guidance is to be provided through estimated relative poses between an ORU (to be retrievedinserted), a robotic arm and the related worksite. The major challenges of this work include objects with highly reflective or mirror surfaces moving with(More)
The quadtree is a hierarchical data structure used for the compact representation of two-dimensional images. It has the advantages of data compression and fast execution of certain feature computations. However, the quadtree representation of an object is heavily affected by its location, orientation, and relative size. If the image of an object is(More)