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Jongmoo Choi

Possible papers associated with this exact author name in Arrow. This page groups case-insensitive exact name matches and is not a full identity disambiguation profile.

7 papers
2 author rows

Possible papers

7

AAAI Conference 2019 Conference Paper

Human Motion Prediction via Learning Local Structure Representations and Temporal Dependencies

  • Xiao Guo
  • Jongmoo Choi

Human motion prediction from motion capture data is a classical problem in the computer vision, and conventional methods take the holistic human body as input. These methods ignore the fact that, in various human activities, different body components (limbs and the torso) have distinctive characteristics in terms of the moving pattern. In this paper, we argue local representations on different body components should be learned separately and, based on such idea, propose a network, Skeleton Network (SkelNet), for long-term human motion prediction. Specifically, at each time-step, local structure representations of input (human body) are obtained via Skel- Net’s branches of component-specific layers, then the shared layer uses local spatial representations to predict the future human pose. Our SkelNet is the first to use local structure representations for predicting the human motion. Then, for short-term human motion prediction, we propose the second network, named as Skeleton Temporal Network (Skel-TNet). Skel-TNet consists of three components: SkelNet and a Recurrent Neural Network, they have advantages in learning spatial and temporal dependencies for predicting human motion, respectively; a feed-forward network that outputs the final estimation. Our methods achieve promising results on the Human3. 6M dataset and the CMU motion capture dataset, and the code is publicly available 1.

AAAI Conference 2018 Conference Paper

SPOT Poachers in Action: Augmenting Conservation Drones With Automatic Detection in Near Real Time

  • Elizabeth Bondi
  • Fei Fang
  • Mark Hamilton
  • Debarun Kar
  • Donnabell Dmello
  • Jongmoo Choi
  • Robert Hannaford
  • Arvind Iyer

The unrelenting threat of poaching has led to increased development of new technologies to combat it. One such example is the use of long wave thermal infrared cameras mounted on unmanned aerial vehicles (UAVs or drones) to spot poachers at night and report them to park rangers before they are able to harm animals. However, monitoring the live video stream from these conservation UAVs all night is an arduous task. Therefore, we build SPOT (Systematic POacher deTector), a novel application that augments conservation drones with the ability to automatically detect poachers and animals in near real time. SPOT illustrates the feasibility of building upon state-of-the-art AI techniques, such as Faster RCNN, to address the challenges of automatically detecting animals and poachers in infrared images. This paper reports (i) the design and architecture of SPOT, (ii) a series of efforts towards more robust and faster processing to make SPOT usable in the field and provide detections in near real time, and (iii) evaluation of SPOT based on both historical videos and a real-world test run by the end users in the field. The promising results from the test in the field have led to a plan for larger-scale deployment in a national park in Botswana. While SPOT is developed for conservation drones, its design and novel techniques have wider application for automated detection from UAV videos.

IROS Conference 2015 Conference Paper

Convex Cut: A realtime pseudo-structure extraction algorithm for 3D point cloud data

  • ChangHyun Jun
  • Jihwan Youn
  • Jongmoo Choi
  • Gérard G. Medioni
  • Nakju Lett Doh

In this paper, a realtime pseudo-structure extraction algorithm for 3D indoor point cloud data (PCD) is proposed. This algorithm is called Convex Cut (CC) because of its two main steps: cutting the PCD with arbitrary planes, and extracting convex parts. CC can be used as a preprocessing module for other existing algorithms to extract static parts in dynamic environments or to represent a principal 3D model of a given PCD. Its calculation time is 24 milliseconds for 50k PCD on a consumer PC, and it yields a precision value of 0. 90 and a recall value of 0. 99 on average in highly dynamic and cluttered environments. Some possible applications are explained such as simultaneous localization and mapping in dynamic environments, efficient dense map representation, robust 3D scan matching with plane features, and natural motion planning.

ICRA Conference 2006 Conference Paper

A Real-time 3D IR Camera based on Hierarchical Orthogonal Coding

  • Sukhan Lee 0001
  • Jongmoo Choi
  • Seungsub Oh
  • Jaehyuk Ryu
  • Jungrae Park

We present a real-time 3D camera based on IR (infrared) structured light suitable for robots working in home environment. First, we implemented a HOC (hierarchical orthogonal coding) based FPGA board. The HOC gives robust depth images because the signal separation coding provides not only the separation of overlapped codes, but also a robust decision on pixel correspondence with error correction. The FPGA module can handle high computational cost of HOC based signal separation coding. Second, we implemented a compact optic system of the camera to project and receive IR structured light. The invisible IR pattern light provides users inconvenient in the home environment. Various objects and workspaces which has continuous and/or non-continuous surface are tested and, sensitivity to illumination change and processing time are analyzed. The experiment results show the robust performance for surface smoothness, color, and materials of objects used in home environment. The proposed approach opens a greater feasibility of applying structured light based depth imaging to a 3D modeling of cluttered workspace for home service robots

IROS Conference 2006 Conference Paper

A Real-Time Wall Detection Method for Indoor Environments

  • Hadi Moradi
  • Jongmoo Choi
  • Eunyoung Kim
  • Sukhan Lee 0001

This paper presents an effective and real-time approach for detecting walls in indoor environment. This approach relies on the fact that the rear of the opaque walls is not visible. Thus, to detect the walls in an indoor environment a set of hypothetical walls, based on the ceiling edges or ground level edges, are considered; and their validity is checked using point cloud, generated by a sensor. A certainty factor is calculated for each detected wall, which is updated continuously based on the newly gathered sensory information. Furthermore, the certainty of the walls can be updated using other source of information for better and more reliable wall detection. The novelty of this approach is in its capability to handle environments, with texture-less walls, in real-time. The algorithm has been implemented in simulation, and tested in real environment and has shown effective, reliable and real-time performance

ICRA Conference 2005 Conference Paper

A 3D IR Camera with Variable Structured Light for Home Service Robots

  • Sukhan Lee 0001
  • Jongmoo Choi
  • Seungmin Baek
  • Byungchan Jung
  • Changsik Choi
  • Hunmo Kim
  • Jeongtaek Oh
  • Seungsub Oh

There has shown a significant interest in a high performance of, at the same time, a compact size and low cost of, 3D sensor, in reflection of a growing need of 3D environmental sensing for service robotics. One of the important requirements associated with such a 3D sensor is that sensing does not irritate or disturb human in any way while working in close and continuous contact with human. Furthermore, such a 3D sensor should be reliable and robust to the change of environmental illumination as service robots are required to work day and night. This paper presents a 3D IR camera with variable structured light that is human friendly and robust enough for application to home service robots. Infrared is chosen as the sensing medium in order to meet the requirement of human friendliness and robustness to illumination change. A Digital Mirror Device (DMD) is employed to generate and project variable patterns at a high speed for real-time operation. In implementation, we emphasize the integration of modular components to support real-time sensing and compactness in size. A number of real-world experimentations are conducted, including a human face, a statue, and a plastic model. The experimental results have demonstrated that the implemented 3D IR Camera is robust to illumination change, in addition to its advantage of human friendliness.

ICRA Conference 2005 Conference Paper

Signal Separation Coding for Robust Depth Imaging Based on Structured Light

  • Sukhan Lee 0001
  • Jongmoo Choi
  • DaeSik Kim
  • Jaekeun Na
  • Seungsub Oh

This paper presents an original approach to coding the light patterns for robust depth imaging based on structured light. We have discovered that the degradation of precision and robustness, seen in most conventional approaches to structured light, comes mainly from the overlapping of multiple codes in the signal received at a camera pixel, where the overlapped codes are from the neighbouring and/or, even, distant pixels of the projecting mirror array. Considering the criticality of separating the overlapped codes to precision and robustness, we propose a novel signal separation code, referred to here as “Hierarchical Orthogonal Code (HOC), ” for depth imaging. HOC provides not only the separation of overlapped codes, but also a robust decision on pixel correspondence with error correction based on a contextual likelihood among the sets of separated codes from neighbouring camera pixels. The experimental results have shown that the proposed HOC significantly enhances the robustness and precision in depth imaging, compared to the best known conventional approaches. The proposed approach opens a greater feasibility of applying structured light based depth imaging to a 3D modelling of cluttered workspace for home service robots.

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