Université de Neuchâtel

Augmented reality using range images

Schütz, Christian L. ; Hügli, Heinz

In: Stereoscopic Displays and Virtual Reality Systems IV (Proceedings of SPIE), 1997, vol. 3012, p. 472-478

This paper proposes range imaging as a means to improve object registration in an augmented reality environment. The addressed problem deals with virtual world construction from complex scenes using object models. During reconstruction, the scene view is augmented by superimposing virtual object representations from a model database. The main difficulty consists in the precise registration of a...

Université de Neuchâtel

Change detection in range imaging for 3D scene segmentation

Schütz, Christian L. ; Hügli, Heinz

In: International Symposium on Lasers, Optics and Vision for Productivity in Manufacturing I (Proceedings of SPIE), 1996, vol. 2786, no. 98, p. 1-9

This paper deals with the problem of segmenting a 3D scene obtained by range imaging. It assumes scenes of arbitrary complexity in which the objects to be recognized are newly added or removed and investigates how the methods of change detection and image difference used in classical image processing can be used in range imaging. In a first step, we consider the case of ideal range images and...

Université de Neuchâtel

How well performs free-form 3D object recognition from range images ?

Hügli, Heinz ; Schütz, Christian L.

In: Photonics East (Proceedings of SPIE), 1996, vol. 2904, no. 9, p. 66-74

This paper investigates the recognition performance of a geometric matching approach to the recognition of free-form objects obtained from range images. The heart of this approach is a closest point matching algorithm which, starting from an initial configuration of two rigid objects, iteratively finds their best correspondence. While the effective performance of this algorithm is known to depend...

Université de Neuchâtel

Pedestrian Detection by Range Imaging

Hügli, Heinz ; Zamofing, Thierry

In: Proceedings. Conference on Computer Vision Theory and Applications (VISAPP), 2007, p. 1-5

Remote detection by camera offers a versatile means for recording people activities. Relying principally on changes in video images, the method tends to fail in presence of shadows and illumination changes. This paper explores a possible remedy to these problems by using range cameras instead of conventional video cameras. As range is an intrinsic measure of object geometry, it is basically not...

Université de Neuchâtel

Time-of-flight imaging of indoor scenes with scattering compensation

Mure-Dubois, James ; Hügli, Heinz

In: Proceedings. Conference Optical 3-D Measurement Techniques, 2007, p. 1-8

3D time-of-flight cameras may suffer from false depth readings caused by light scattering. In order to reduce such scattering artifacts, a scattering compensation procedure is proposed. Assuming a space invariant point spread function as a model for the scattering leads to a solution in a form of a deconvolution scheme.The improvemen tbrought by scattering compensation, as well as the...

Université de Neuchâtel

Free-form 3D object reconstruction from range images

Schütz, Christian ; Jost, Timothée ; Hügli, Heinz

In: Proceedings. International Conference on Virtual Systems and MultiMedia (VSMM '97), 1997, p. 69-80

The increasing use of virtual object representations for several applications creates a need for fast and simple object digitizing systems. Range finders provide a convenient way to digitize solid objects and permit the accurate and fast scanning of an object shape without any probe contact. However, only one view of an object can be captured at once, and therefore, for most objects, several...

Université de Neuchâtel

Geometric matching for free-form 3D object recognition

Hügli, Heinz ; Schütz, Christian ; Semitekos, Dimitrios

In: Proceeding ACCV'95 (Asian Conference on Computer Vision), 1995, p. 1-6

This paper investigates a new approach to the recognition of 3D objects of arbitrary shape. The proposed solution follows the principle of model-based recognition using geometric 3D models and geometric matching. It is an alternative to the classical segmentation and primitive extraction approach and provides a perspective to escape the difficulties found with it when dealing with free-form...

Université de Neuchâtel

Recognition of 3-D objects with a closest point matching algorithm

Schütz, Christian ; Hügli, Heinz

In: From Pixels to Sequences - Sensors, algorithms and systems (Proceedings conference ISPRS intercommission workshop), 1995, vol. 30, no. 5W1, p. 128-133

This paper is a contribution to the recognition of arbitrary 3-D shapes from range images. Recently, a closest point matching algorithm was proposed that is in a position to match 3-D shapes without the need of an explicit object description in terms of primitives. The advantage is that the comparison works directly on the 3-D coordinates of the surface points and needs neither segmentation nor...

Université de Neuchâtel

Optimized scattering compensation for time-of-flight camera

Mure-Dubois, James ; Hügli, Heinz

In: Two- and Three-Dimensional Methods for Inspection and Metrology V (Proceedings of SPIE), 2007, vol. 6762, no. 67620H, p. 1-10

Recent time-of-flight (TOF) cameras allow for real-time acquisition of range maps with good performance. However, the accuracy of the measured range map may be limited by secondary light reflections. Specifically, the range measurement is affected by scattering, which consists in parasitic signals caused by multiple reflections inside the camera device. Scattering, which is particularly strong in...

Université de Neuchâtel

Embedded 3D vision system for automated micro-assembly

Mure-Dubois, James ; Hügli, Heinz

In: Two- and Three-Dimensional Methods for Inspection and Metrology IV (Proceedings of SPIE), 2008, vol. 6382, no. 63820J, p. 1-11

Machine vision plays an important role in automated assembly. However, present vision systems are not adequate for robot control in an assembly environment where individual components have sizes in the range of 1 to 100 micrometers, since current systems do not provide sufficient resolution in the whole workspace when they are fixed, and they are too bulky to be brought close enough to the...