Exclusively from Cambridge: Creating 3D models with a simple webcam

18 December 2009 by Anna Mieczakowski  
Filed under News and views

Yet another great discovery to join the University of Cambridge’s cabinet of fame as researchers at the Engineering Department created a program able to build 3D models of textured objects in real-time, using only a standard computer and webcam. Up to this point, the construction of virtual 3D models usually required heavy and expensive equipment, was time-consuming and complicated to use or inconvenient and the model was not built in real-time. The existing methods for capturing 3D models range from 2D/3D laser, (in visible spectrum or other wave lengths), scanner, projector, camera, etc. The data (for example laser information or photos) must first be acquired, before going through the lengthy reconstruction process to form the model. If the 3D reconstruction is unsatisfactory, then the data must be acquired again.

The new method for capturing 3D models needs only a simple webcam. The object is moved about in front of the webcam and the software can reconstruct the object “on-line” while collecting live video. The system uses points detected on the object to estimate object structure from the motion of the camera or the object, and then computes the Delaunay tetrahedralisation of the points (the extension of the 2D Delaunay triangulation to 3D). The points are recorded in a mesh of tetrahedra, within which is embedded the surface mesh of the object. The software can then tidy up the final reconstruction by taking out the invalid tetrahedra to obtain the surface mesh based on a probabilistic carving algorithm, and the object texture is applied to the 3D mesh in order to obtain a realistic model. Thanks to this simple and cheap system, 3D reconstruction can become accessible to everybody.

Demonstration of what the new 3D modelling method requires and how it should be used can be viewed here.

Exclusively from Cambridge: P3 – a new approach for supporting design process

17 December 2009 by Anna Mieczakowski  
Filed under News and views

A few weeks ago I wrote a post about DRed, a leading-edge software developed by researchers from the University of Cambridge for unobtrusively capturing, graphically presenting, and storing for future reuse, the rationale behind the day to day decisions of individuals or groups of designers. Today, I am going to look at P3 Signposting, which is a rich, graphical framework for manipulating and simulating Applied Signposting Models (ASMs) ranging from descriptive flowcharts used to capture expert knowledge through to executable models, in which parameters represent data files that are processed by tasks which drive execution of design codes. Similarly to DRed, P3 has been developed at the University of Cambridge by and it has been tested and used on daily basis by designers and engineers from a leading British aerospace organisation, in particular, Rolls-Royce Civil Aerospace.

The P3 software is aimed at companies which develop complex products/systems such as a gas turbine and may be used to model design processes at varying levels of abstraction. It can capture down to a very low level what is going on within a given product/system and yet package away all the core interactions between sub-processes. P3 is based on a graphical diagramming interface which should be familiar to users of standard office suites. It is intended to provide an alternative to general-purpose diagramming tools or spreadsheets and can be configured without programming to implement novel modelling frameworks.

In P3 diagrammatic models of any type are comprised of worksheets, nodes and node ports, edges and constraints:

  1. Worksheets. Each worksheet may contain multiple nodes and edges. Worksheets may be to split a large model for easier navigation and printing (for graphical reasons) and to give different meaning to sections of the model. Multiple worksheets may be created and may optionally be nested within one another.
  2. Nodes and node ports. Each node on a worksheet is an instance of a particular class defined in the linkage meta-model. Model instances are referred to as elements and model classes are referred to as schemas. An element schema determines the data fields which are presented to the user to edit the properties of elements of that type. Element schemas also determine how nodes are rendered in the diagramming view, by combining simple geometric primitives which render rectangles, ellipses, text strings etc. Every element schema must also define one or more node ports. Each node port is a part of the node geometry which has a particular meaning in the modelling framework.
  3. Edges. Edges connect one node port to another, either on the same node or on two different nodes. The type of an edge is determined by an edge schema defined in a similar way to element.

In addition to implementing the Applied Signposting approach, P3 allows rapid prototyping of other linkage-based modelling frameworks. A graphical configuration tool allows extension or re-definition of the modelling framework by declaring new element classes, properties, relations and perspectives.

P3 is a useful tool for designing products/systems during the design process and it has been successfully used in academia and industry for about 3 years and, since it is under active development, it includes an online update feature.