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 presents a new approach for the classification and retrieval of three-dimensional images and models from databases. A set of retrieval algorithms is introduced. These algorithms are content-based, meaning that the input is, not made out of keywords but of three-dimensional models. Tensor of inertia, distribution of normals and distribution of cords are used to describe each model. The database can be searched by scale, shape or color or any combination of these parameters. A user friendly interface makes the retrieval operation simple and intuitive and allows to edit reference models according to the specifications of the user. Experimental results using a database of more than 400 range images and 1000 VRML models are presented.

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.

A method of estimating range flow (space displacement vector field) on nonrigid as well as rigid objects from a sequence of range images is described. This method can directly estimate the deformable motion parameters by solving a system of linear equations that are obtained from substituting a linear transformation of nonrigid objects expressed by the Jacobian matrix into motion constraints based on an extension of the conventional scheme used in intensity image sequences. The range flow is directly computed by substituting these estimated motion parameters into the linear transformation. The algorithm is supported by experimental estimations of range flow on a sheet of paper, a piece of cloth, human skin, and a rubber balloon being inflated, using real range image sequences acquired by a video rate range camera.>

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 system for simultaneously measuring the 3-D shape and color properties of objects is described. Range data are obtained by triangulation over large volumes of the scene, whereas color components are separated by means of a white laser. Details are given concerning the modeling and the calibration of the system for bidirectional reflectance-distribution functions measurements. A reflection model is used to interpret the data collected with the system in terms of the underlying physical properties of the target. These properties are the diffuse reflectance of the body material, the Fresnel reflectance of the air media interface, and the slope surface roughness of the interface. Experimental results are presented for the extraction of these parameters. By allowing the subtraction of highlights from color images and the compensation for surface orientation, spectral reflectance modeling can help to understand 3-D scenes. A practical example is given where a color and range image is processed to yield uniform regions according to material pigmentation.>

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 method is described for estimating range flow (space displacement vector field) on a nonrigid object as well as a rigid object from a sequence of range images. The method can directly estimate the deformable motion parameters by solving a system of linear equations which are obtained by substituting a linear transformation of a nonrigid object expressed by a Jacobian matrix into motion constraints based on an extension of the conventional scheme used in intensity image sequences, and the range flow is obtained from the motion parameters and linear transformation. The algorithm is supported by experiments of motion estimation of a sheet of paper, a piece of cloth, the movement of human skin, and the motion of a rubber balloon being inflated using real range image sequences acquired by a video rate range finder. Furthermore, it is shown that by adding the intensity image sequence to the range information, one can prevent the equation system from falling in an ill-posed condition.>

A computer vision system is presented for shape synthesis and recognition of three-dimensional objects using an attributed hypergraph representation. The vision system is capable of: (1) constructing an attributed hypergraph representation (AHR) based on the information extracted from an image with range data; (2) synthesizing several AHRs obtained from various views of an object to form a complete AHR of the object; and (3) recognizing any view of an object of finding the graph monomorphism between the AHR of that view and the complete AHR of a prototype object. This system is implemented on a Grinnell imaging system driven by a VAX 11/750 running VMS.>