We present a system for accurate real-time mapping of complex and arbitrary indoor scenes in variable lighting conditions, using only a moving low-cost depth camera and commodity graphics hardware. We fuse all of the depth data streamed from a Kinect sensor into a single global implicit surface model of the observed scene in real-time. The current sensor pose is simultaneously obtained by tracking the live depth frame relative to the global model using a coarse-to-fine iterative closest point (ICP) algorithm, which uses all of the observed depth data available. We demonstrate the advantages of tracking against the growing full surface model compared with frame-to-frame tracking, obtaining tracking and mapping results in constant time within room sized scenes with limited drift and high accuracy. We also show both qualitative and quantitative results relating to various aspects of our tracking and mapping system. Modelling of natural scenes, in real-time with only commodity sensor and GPU hardware, promises an exciting step forward in augmented reality (AR), in particular, it allows dense surfaces to be reconstructed in real-time, with a level of detail and robustness beyond any solution yet presented using passive computer vision.

/pdf/kinectfusion-real-time-dense-surface-mapping-and-tracking-pl8e8pbmre.pdf

KinectFusion: Real-time dense surface mapping and tracking

This paper describes a new method for contouring a signed grid whose edges are tagged by Hermite data (i.e; exact intersection points and normals). This method avoids the need to explicitly identify and process "features" as required in previous Hermite contouring methods. Using a new, numerically stable representation for quadratic error functions, we develop an octree-based method for simplifying contours produced by this method. We next extend our contouring method to these simpli£ed octrees. This new method imposes no constraints on the octree (such as being a restricted octree) and requires no "crack patching". We conclude with a simple test for preserving the topology of the contour during simplification.

/pdf/dual-contouring-of-hermite-data-3xd1h9wqp6.pdf

Dual contouring of hermite data

We address the problem of building watertight 3D models from surfaces that contain holes - for example, sets of range scans that observe most but not all of a surface. We specifically address situations in which the holes are too geometrically and topologically complex to fill using triangulation algorithms. Our solution begins by constructing a signed distance function, the zero set of which defines the surface. Initially, this function is defined only in the vicinity of observed surfaces. We then apply a diffusion process to extend this function through the volume until its zero set bridges whatever holes may be present. If additional information is available, such as known-empty regions of space inferred from the lines of sight to a 3D scanner, it can be incorporated into the diffusion process. Our algorithm is simple to implement, is guaranteed to produce manifold non-interpenetrating surfaces, and is efficient to run on large datasets because computation is limited to areas near holes.

/pdf/filling-holes-in-complex-surfaces-using-volumetric-diffusion-2086jyfy19.pdf

Filling holes in complex surfaces using volumetric diffusion

The invention provides methods and devices for fabricating printable semiconductor elements and assembling printable semiconductor elements onto substrate surfaces. Methods, devices and device components of the present invention are capable of generating a wide range of flexible electronic and optoelectronic devices and arrays of devices on substrates comprising polymeric materials. The present invention also provides stretchable semiconductor structures and stretchable electronic devices capable of good performance in stretched configurations.

Methods and devices for fabricating and assembling printable semiconductor elements

We present a method for simulating water and smoke on an unrestricted octree data structure exploiting mesh refinement techniques to capture the small scale visual detail. We propose a new technique for discretizing the Poisson equation on this octree grid. The resulting linear system is symmetric positive definite enabling the use of fast solution methods such as preconditioned conjugate gradients, whereas the standard approximation to the Poisson equation on an octree grid results in a non-symmetric linear system which is more computationally challenging to invert. The semi-Lagrangian characteristic tracing technique is used to advect the velocity, smoke density, and even the level set making implementation on an octree straightforward. In the case of smoke, we have multiple refinement criteria including object boundaries, optical depth, and vorticity concentration. In the case of water, we refine near the interface as determined by the zero isocontour of the level set function.

/pdf/simulating-water-and-smoke-with-an-octree-data-structure-3cgy6zahqn.pdf

Simulating water and smoke with an octree data structure

This paper presents Kizamu, a computer-based sculpting system for creating digital characters for the entertainment industry. Kizamu incorporates a blend of new algorithms, significant technical advances, and novel user interaction paradigms into a system that is both powerful and unique.To meet the demands of high-end digital character design, Kizamu addresses three requirements posed to us by a major production studio. First, animators and artists want digital clay — a medium with the characteristics of real clay and the advantages of being digital. Second, the system should run on standard hardware at interactive rates. Finally, the system must accept and generate standard 3D representations thereby enabling integration into an existing animation production pipeline.At the heart of the Kizamu system are Adaptively Sampled Distance Fields (ADFs), a volumetric shape representation with the characteristics required for digital clay. In this paper, we describe the system and present the major research advances in ADFs that were required to make Kizamu a reality.

https://www.ronaldperry.org/SIG2001_Kizamu.pdf

Kizamu: a system for sculpting digital characters

Quadtrees and octrees are used extensively throughout computer graphics and in many other diverse fields such as computer vision, robotics, and pattern recognition. Managing information stored in quadtrees and octrees requires basic tree traversal operations such as point location, region location, and neighbor searches. This paper presents simple and efficient methods for performing these operations that are inherently nonrecursive and reduce the number of comparisons with poor predictive behavior. The methods are table-free, thereby reducing memory accesses, and generalize easily to higher dimensions. Source code is available online.

/pdf/simple-and-efficient-traversal-methods-for-quadtrees-and-9txa3f3akz.pdf

Simple and Efficient Traversal Methods for Quadtrees and Octrees

A method and apparatus antialias a region of a two-dimensional distance field representing an object. The two-dimensional distance field is partitioned into cells where each cell includes a method for reconstructing the two-dimensional distance field within the cell. A set of cells of the two-dimensional distance field associated with the region is identified and a set of pixels associated with the region is located. For each pixel, a set of components is specified. For each component, a distance is determined from the set of cells and then mapped to the antialiased intensity of the component of the pixel.

Method for antialiasing an object represented as a two-dimensional distance field in object-order

We describe a new approach to shape representation called a composite adaptively sampled distance field (composite ADF) and describe its application to NC milling simulation. In a composite ADF each shape is represented by an analytic or procedural signed Euclidean distance field and the milled workpiece is given as the Boolean difference between distance fields representing the original workpiece volume and distance fields representing the volumes of the milling tool swept along the prescribed milling path. The computation of distance field of the swept volume of a milling tool is handled by an inverted trajectory approach where the problem is solved in tool coordinate frame instead of a world coordinate frame. An octree bounding volume hierarchy is used to sample the distance functions and provides spatial localization of geometric operations thereby dramatically increasing the speed of the system. The new method enables very fast simulation, especially of free-form surfaces, with accuracy better than 1 micron, and low memory requirements. We describe an implementation of 3 and 5-axis milling simulation.

/pdf/high-accuracy-nc-milling-simulation-using-composite-27bdlsx4ga.pdf

High accuracy NC milling simulation using composite adaptively sampled distance fields

A camera generates a textured range image. The camera includes a single lens, and a flash substantially co-located with the lens. The camera acquires a first image of a scene from a point of view with ambient light, and a second image of the scene from the point of view with direct light of the flash. The first image and the seconds image are then combined by a divider to generate the textured range image.

Sarah F. Frisken

Papers

Kizamu: a system for sculpting digital characters

Simple and Efficient Traversal Methods for Quadtrees and Octrees

Method for antialiasing an object represented as a two-dimensional distance field in object-order

High accuracy NC milling simulation using composite adaptively sampled distance fields

Single lens 3D camera