This paper proposes a hybrid software-hardware high-resolution projection system for 3D imaging based on fringe projection. The proposed solution combines the advantages of a digital projection with those of an analogue one. It is programmable and allows a high projection rate by avoiding mechanical displacements in the projection system. Moreover, it does not suffer from the limitations of digital systems such as the presence of inter-pixel gaps and limited resolution. The proposed projection system is relatively inexpensive to build since it is composed of a simple arrangement off-the-shelf components. The system is a combination of a low-resolution digital device such as a DMD, LCoS or LCD, some optical components and software to generate the fringe patterns. A prototype of a 3D scanner based on the proposed projection system is used to asses the fitness of the proposed technology.

This paper proposes a novel and efficient representation of the point-spread function (PSF) well suited for structured light systems used in digital profilometry. For this particular application the PSF is spatially variant over the working volume and the current parametric as well as non-parametric representations are insufficient. We validate our method using a standard data set and imagery acquired using an off-the-shelf multimedia projector and an industrial camera.

This paper presents a new technique for fast, view-dependent, real-time visualization of large multiresolution geometric models with color or texture information. This method uses geomorphing to smoothly interpolate between geometric patches composing a hierarchical level-of-detail structure, and to maintain seamless continuity between neighboring patches of the model. It combines the advantages of view-dependent rendering with numerous additional features: the high performance rendering associated with static preoptimized geometry, the capability to display at both low and high resolution with minimal artefacts, and a low CPU usage since all the geomorphing is done on the GPU. Furthermore, the hierarchical subdivision of the model into a tree structure can be accomplished according to any spatial or topological criteria. This property is particularly useful in dealing with models with high resolution textures derived from digital photographs. Results are presented for both highly tesselated models (372 million triangles), and for models which also contain large quantities of texture (200 million triangles + 20 GB of compressed texture). The method also incorporates asynchronous out-of-core model management. Performances obtained on commodity hardware are in the range of 50 million geomorphed triangles/second for a benchmark model such as Stanford's St. Matthew dataset.

Abstract The National Research Council of Canada (NRC) has developed and patented three high‐resolution 3D imaging systems and processing algorithms which have been applied to a wide range of museum and heritage recording applications. The systems have been designed for different imaging applications and, in collaboration with a number of national and international museums and cultural agencies, have been used to scan a wide variety of objects and sites. The objective of this paper is to present a summary of the 3D technology and examples of its heritage applications. Copyright © 2003 John Wiley & Sons, Ltd.

Discusses the progress and the evolution of the development of range sensing techniques at the NRC laboratories. Essentially a 3D imaging project at the beginning, it has evolved to a new media project which requires the development of new tools for 3D modeling, editing, database searching and visualization. Generic applications related to documentation, inspection, target tracking and visual communication will be discussed.

This paper describes sensors and algorithms developed and used for the creation of coloured 3-D triangular meshes from a set of range images with registered colour measurements. The objective is the creation of a digital model of a real object that is compatible with established computer graphics techniques. Triangular meshes are the fundamental rendering primitive supported by most high performance graphics workstations. The surface colour of objects can be represented by attributing reflectance values to the vertices of the mesh. Such a geometric and reflectance model provides a uniform and general representation for sculptured surfaces with non-uniform colouring.

Introduces a new method for the calibration of a range camera based on active triangulation. The technique is based on a model derived from the geometry of the synchronized scanner. From known positions of a calibration bar, a logistic equation is fitted with values of spot positions read from a linear position detector at a number of angular positions of a scanning mirror. Furthermore, with an approximate form of the general equations describing the geometry, a series of design guidelines are derived to help a designer conduct a preliminary study of a particular range camera. Experimental results demonstrating the technique are found to compare favorably with theoretical predictions.>

A very compact optical range sensor is described which is to be used for the acquisition of the range information for the navigation of a mobile platform. A short review of the techniques currently used to acquire range data for a mobile vehicle is included. Some advantages and disadvantages of the different methods are presented. Emphasis is placed on a possible short-to-medium-term solution of the problem of robot navigation. A short description of the optical principle of the range sensor BIRIS, its real-time implementation on a commercially available image processing system, and its performance are presented. The high immunity of the sensor to ambient illumination and external perturbations is also demonstrated. Experimental results and a technique for the detection of the free space surrounding the vehicle using the range data are given.>

A technique for the detection of depth and orientation discontinuities in range images is described. This method uses basic morphological operators to extract these discontinuities from a dense range map. The authors describe how to extract depth discontinuities using the morphological edge operator of J.S.J. Lee et al. (1987) and how to use a top-hat operator to localize the exact positions of these discontinuities. The detection of orientation discontinuities is then discussed in detail. The calculation of a good estimate of the surface normals using anisotropic filtering inhibited at depth discontinuities is demonstrated. Once these estimates of the normals are calculated, operations similar to those used in depth discontinuity detection are used to locate orientation discontinuities at abrupt variations of the surface normals. Experimental results demonstrate computation of the positions of these discontinuities at pixel precision as well as very efficient use of morphological operators to localize abrupt variations in a noisy image signal in less than 1 s using a Datacube image processor.>