Fossil-bearing Citalang Formation, Sumedang-Majalengka, West Java

The Citalang Formation in Sumedang-Majalengka area comprises of various lithological units, including coarse-grained sandstones to conglomerates, greenish grey to dark grey claystone with sandstone and tuff interbeds, and pumice-bearing tuffaceous sandstones and tuff. All these units occur in the lower part of the formation and the contacts with older, underlying rock units are unconformable in several places.Vertebrate fossil fragments are frequently found in the lowermost part of the formation, especially within the coarse-grained sandstones to conglomerates unit. This unit also holds stone tools artefacts, which were made from different kind of stones and show quite simple or primitive shape. The age of Citalang Formation is not yet resolved and still needs to be researched. Some published literatures suggest Pleistocene while there are others that suggest Pliocene.

Pose Estimation of Primitive-Shaped Objects from a Depth Image Using Superquadric Representation

This paper presents a method for estimating the six Degrees of Freedom (6DoF) pose of texture-less primitive-shaped objects from depth images. As the conventional methods for object pose estimation require rich texture or geometric features to the target objects, these methods are not suitable for texture-less and geometrically simple shaped objects. In order to estimate the pose of the primitive-shaped object, the parameters that represent primitive shapes are estimated. However, these methods explicitly limit the number of types of primitive shapes that can be estimated. We employ superquadrics as a primitive shape representation that can represent various types of primitive shapes with only a few parameters. In order to estimate the superquadric parameters of primitive-shaped objects, the point cloud of the object must be segmented from a depth image. It is known that the parameter estimation is sensitive to outliers, which are caused by the miss-segmentation of the depth image. Therefore, we propose a novel estimation method for superquadric parameters that are robust to outliers. In the experiment, we constructed a dataset in which the person grasps and moves the primitive-shaped objects. The experimental results show that our estimation method outperformed three conventional methods and the baseline method.

3D Object Detection and Scene Optimization for Tangible Augmented Reality

Object recognition in 3D scenes is one of the fundamental tasks in computer vision. It is used frequently in robotics or augmented reality applications [1]. In our work we intend to apply 3D shape recognition to create a Tangible Augmented Reality system that is able to pair virtual and real objects in natural indoors scenes. In this paper we present a method for arranging virtual objects in a real-world scene based on primitive shape graphs. For our scheme, we propose a graph node embedding algorithm for graphs with vectorial nodes and edges, and genetic operators designed to improve the quality of the global setup of virtual objects. We show that our methods improve the quality of the arrangement significantly.

Automatic modelling of building façade objects via primitive shapes

This paper presents a new approach to recognize individual façade objects and to reconstruct such objects in 3D using MLS point clouds. Core of the approach is a primitive shape based algorithm, which introduces building primitives, to identify the façade objects separately from other irrelevant objects and then to model the correct topology. The primitive shape is identified against defined different primitive shapes by using the Douglas-Peucker algorithm. The advantage of this process is that it offers an ability not only to model correct geometric shapes but also to remove occlusion effects from the final model. To evaluate the validity of the proposed approach, experiments have been conducted using two types of street scene point clouds captured by Optech Lynx Mobile Mapper System and Z+F laser scanner. Results of the experiments show that the completeness, correctness, and quality of the reconstructed building façade objects are well over 90 %, proving the proposed method is a promising solution for modelling 3D façade objects with different geometric shapes.

Design of a Simple Underactuated Mechanical Gripper

The objective of this paper is to design and develop a simple geometry of an underactuated mechanical gripper which can provide most common hand grasps, fingertip grasp and enveloping grasp. The gripper consists of 2 2-DOF fingers underactuated by a pulley-tendon system, and a movable pulley for underactuation between fingers. Each finger has 2 links and 2 pulleys. A parallel linkage is used to translate distal phalanx toward an object such that fingertip grasp is improved. This work implements stability and force isotropy criteria to optimize the design. The prototype has 0.43 of pulley-radius ratio and 1.72 of link-length ratio. From primitive-shape grasping test, the gripper is able to achieve the stable configuration.