Analysis of shapes to measure surfaces: An approach for detection of deformations

This paper presents a method to analyse 3D planar surfaces and to measure variations on it. The method is oriented to the detection of deformations on the elastic object surfaces formed by flat faces. These deformations are usually caused when two bodies, a solid and another elastic object, come in contact and there are contact pressures among their faces. Our method describes a strategy to model the shape of deformation using a mathematical approach based on two concepts: Histogram and Map of curvature. In particular, we describe the algorithm for deformations in order to use it in visual control and inspection tasks for manipulation processes with robot hands. Several experiments and their results are shown to evaluate the validity and robustness of the method to detect and measure deformations in grasping tasks. To do it, some virtual scenarios were created to simulate contacts with fingers of a hand robot.

1 Introduction

Generally, researchers about robotic manipulation have been focused to recognize rigid objects such as solids [Saxena et al., 2008]. But, in recent years, the manipulation process has changed to recognize articulated objects [Katz, 2008], deformable objects [Hirai et al., 2001] such as soft objects [Berenson, 2013], semi-solids such as organic material [Gemici et al., 2014] or tissue [Ramisa et al., 2013]. Therefore, three basic types of rigid objects can be considered solids, elastics and deformable objects.