Active, optical range imaging systems collect three-dimensional coordinate data from object surfaces. These systems can be useful in a wide variety of automation applications, including shape acquisition, bin picking, assembly, inspection, gauging, robot navigation, medical diagnosis, cartography, and military tasks. The range-imaging sensors in such systems are unique imaging devices in that the image data points explicitly represent scene surface geometry in a sampled form. At least six different optical principles have been used to actively obtain range images: (1) radar, (2) triangulation, (3) moire, (4) holographic interferometry, (5) lens focusing, and (6) diffraction. The relative capabilities of different sensors and sensing methods are evaluated using a figure of merit based on range accuracy, depth of field, and image acquisition time.

Active optical range imaging sensors

This paper presents a comparative study and survey of model-based object-recognition algorithms for robot vision. The goal of these algorithms is to recognize the identity, position, and orientation of randomly oriented industrial parts. In one form this is commonly referred to as the "bin-picking" problem, in which the parts to be recognized are presented in a jumbled bin. The paper is organized according to 2-D, 2½-D, and 3-D object representations, which are used as the basis for the recognition algorithms. Three central issues common to each category, namely, feature extraction, modeling, and matching, are examined in detail. An evaluation and comparison of existing industrial part-recognition systems and algorithms is given, providing insights for progress toward future robot vision systems.

Model-based recognition in robot vision

Given a triangulation of a simple polygonP, we present linear-time algorithms for solving a collection of problems concerning shortest paths and visibility withinP. These problems include calculation of the collection of all shortest paths insideP from a given source vertexS to all the other vertices ofP, calculation of the subpolygon ofP consisting of points that are visible from a given segment withinP, preprocessingP for fast "ray shooting" queries, and several related problems.

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Linear-time algorithms for visibility and shortest path problems inside triangulated simple polygons

We consider the problem of computing geometric transformations (rotation, translation, reflexion) that map a point setA exactly or approximately into a point setB. We derive efficient algorithms for various cases (Euclidean or maximum metric, translation or rotation, or general congruence).

/pdf/congruence-similarity-and-symmetries-of-geometric-objects-4h3xm6gruz.pdf

Congruence, similarity, and symmetries of geometric objects

In the arts and sciences, as well as in our daily lives, symmetry has made a profound and lasting impact. Likewise, a computational treatment of symmetry and group theory (the ultimate mathematical formalization of symmetry) has the potential to play an important role in computational sciences. Though the term Computational Symmetry was formally defined a decade ago by the first author, referring to algorithmic treatment of symmetries, seeking symmetry from digital data has been attempted for over four decades. Computational symmetry on real world data turns out to be challenging enough that, after decades of effort, a fully automated symmetry-savvy system remains elusive for real world applications. The recent resurging interests in computational symmetry for computer vision and computer graphics applications have shown promising results. Recognizing the fundamental relevance and potential power that computational symmetry affords, we offer this survey to the computer vision and computer graphics communities. This survey provides a succinct summary of the relevant mathematical theory, a historic perspective of some important symmetry-related ideas, a partial yet timely report on the state of the arts symmetry detection algorithms along with its first quantitative benchmark, a diverse set of real world applications, suggestions for future directions and a comprehensive reference list.

https://www.nowpublishers.com/article/DownloadSummary/CGV-008

Computational Symmetry in Computer Vision and Computer Graphics

Optimal algorithms for finding the symmetries of a planar point set

We describe an apparatus for obtaining three-dimensional surface information that may be used to recognize objects and determine their position and orientation. A lightweight camera and a light-stripe projector using an infrared laser diode are mounted in the hand of a robot manipulator. Image-processing routines locate the stripe in the camera image, and homogeneous coordinate transform techniques are then applied to solve for the three-dimensional coordinates of points illuminated by the stripe. We describe the hardware, the equations for coordinate measurement and the procedures for accurately calibrating the apparatus.© (1983) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Movable Light-Stripe Sensor For Obtaining Three-Dimensional Coordinate Measurements

The ears of a polygon

: The main goal of this project is to produce a representational scheme that can be used to compare shape descriptions of solid three-dimensional objects. We are working toward a demonstration to show recognition and determination of position and orientation of solid objects on a tabletop, using a sensor consisting of a light-stripe projector and camera mounted in the hand of a robot manipulator. This report presents the results of a number of activities directed toward that goal: calibration and use of the range finder, a tactile sensor for exploring a three-dimensional domain, a system for identifying pipes in a bin, a method for assessing the similarity of cross- section curves, and pose cluster matching, a new technique for shape matching.

Three-dimensional sensing and interpretation

We describe an apparatus for obtaining three -dimensional surface information that may be used to recognize objects and determine their position and orientation. A lightweight camera and a lightstripe projector using an infrared laser diode are mounted in the hand of a robot manipulator. Image -processing routines locate the stripe in the camera image, and homogeneous coordinate transform techniques are then applied to solve for the three -dimensional coordinates of points illuminated by the stripe. We describe the hardware, the equations for coordinate measurement and the procedures for accurately calibrating the apparatus.

Peter T. Highnam

Papers

Optimal algorithms for finding the symmetries of a planar point set

Movable Light-Stripe Sensor For Obtaining Three-Dimensional Coordinate Measurements

The ears of a polygon

Three-dimensional sensing and interpretation

We describe an apparatus