Luc Cournoyer | NRC-IIT - Academia.edu (original) (raw)
Papers by Luc Cournoyer
A portable digital 3D imaging system based on laser triangulation was designed for the accurate d... more A portable digital 3D imaging system based on laser triangulation was designed for the accurate documentation of environments and objects located in remote sites. Cultural heritage and industrial applications are among the best candidates to benefit from this new technology. This paper focuses on such aspects as the acquisition, display, calibration/verification, and especially on model building. These aspects were all optimized to create a versatile system that is truly portable, i.e. hand portable to a remote site. Emphasis is placed on accuracy verification and monitoring which are critical factors for obtaining high-quality reconstruction of 3D models from multiple range images. A summary of the experimental results acquired at a number of sites in Italy is presented in this paper
Journal of Visualization and Computer Animation, 2003
This paper presents the project &... more This paper presents the project "Development of Geographic Information Systems at the Acropolis of Athens", financed by the European Union and the Government of Greece. The Acropolis of Athens is one of the major archaeological sites world-wide included in the UNESCO World Heritage list. The project started in June 2007 and will finish at the end of 2008. The paper
Optical Engineering, 1992
A video rate laser range finder based on the autosynchronized scanning approach is presented. The... more A video rate laser range finder based on the autosynchronized scanning approach is presented. The range camera simultaneously provides range and intensity information of a scene in EIA- RS-170 format. A spatial resolution of 420 horizontal lines each having 512 pixels was achieved at a rate of 30 images per second. A wide dynamic range in intensity (16 bits) coupled with drift compensation allows this sensor to achieve a range resolution of 8 bits. The volume of view is 50 X 50 X 50 mm.
Applied Optics, 1991
A fast, range imaging, eye-safe laser scanner which uses a synchronized scanning geometry is desc... more A fast, range imaging, eye-safe laser scanner which uses a synchronized scanning geometry is described. The device operates at a 1.5-microm wavelength and incorporates an Er doped fiber laser as well as an InGaAs position sensitive detector. Factors influencing device performances are presented along with range images obtained at 1.5 microm.
This paper discuses the development of a short wavelength infrared laser ranging scanner system a... more This paper discuses the development of a short wavelength infrared laser ranging scanner system at the Canadian Space Agency in cooperation with the National Research Council Canada. A laser source at 1.54 micrometers wavelength is chosen for its relatively eye-safe property. The scanner system is to be considered for use as a space vision system for applications such as robot
An important application of laser range sensing is found in the 3D scanning and modelling of heri... more An important application of laser range sensing is found in the 3D scanning and modelling of heritage collections, and of sculptures in particular. Since a significant proportion of the statues in the world's museums is composed of marble, the optical properties of this material under laser range sensing need to be understood. Marble's translucency and heterogeneous structure produce significant bias and increased noise in the geometric measurements. Experiments on a sample of Carrara Statuario marble highlight the relationship between the laser spot diameter and the estimated noise levels in the geometric measurements. A bias in the depth measurement is also observed. These phenomena are believed to result from scattering on the surface of small crystals at or near the surface.
This work is part of the project "Development of Geographic Information Systems at the Acropolis ... more This work is part of the project "Development of Geographic Information Systems at the Acropolis of Athens". Within this project one of the aims is the generation of a textured, high-resolution, accurate 3D model of the Erechtheion and a realistic computer animation. For most parts, we used a medium-range time-of-flight (TOF) phase-based laser scanner with minimum lateral data spacing of 1 mm and depth uncertainty of 0.2 mm. We also used high-resolution digital images for image-based reconstruction on some parts and for texture mapping. We present data capture, processing, and model generation techniques with emphasis on the encountered problems and solutions when dealing with a large complex structure, huge datasets, and field work under time constraints and challenging conditions. The experience gained, and the tools adapted for some tasks, will be valuable for other large-scale 3D modelling projects.
As electronic documents are becoming more and more popular, variety of objects, including 2D and ... more As electronic documents are becoming more and more popular, variety of objects, including 2D and 3D objects such as articles, books and 3D-shapes, can be easily contained in a document. Conventional systems cannot capture these objects as a 3D form. We developed a new image capturing system with 3D information for deskwork. It is an assemblage of a normal digital camera and its docking station designed for easy operation. The docking station swings the attached camera tilting step by step. Within a few steps, it covers the whole object automatically. Then each frame is combined together into one complete image with full resolution. In order to get precise 3D structure, stripe patterns are projected by a modified flash light attached on the camera. The resolution rises by means of the swing to be slipped the patterns on the object. Using the obtained 3D data we can reconstruct a correct image from a splay surface image such as a book. Experimental Results of image mosaicing and 3D reconstruction shows that the system is practical.
The Grotta dei Cervi is a complex and fragile Neolithic cave where human presence left a large nu... more The Grotta dei Cervi is a complex and fragile Neolithic cave where human presence left a large number of unique pictographs and petroglyphs. Detailed documentation necessitates recording it at different levels of details or spatial resolutions. A general approach would entail a combination of 3D data from different 3D sensors and information from different sources in order to meet set resolution targets. We used a prototype multi-resolution 3D laser imaging scanner that allowed acquiring the shape information of the three main chambers with a spatial resolution that improves with shorter standoffs. The system can record 3D data at a camera-to-object distance which ranges from 0.5 m to 10 m. At a standoff of 0.75 m, it provides a depth uncertainty of 0.08 mm and an optical lateral resolution of 0.2 mm on actual rock surfaces. This paper presents the project and the results obtained. The 10-day long visit into the Grotto generated more that 100 GB of 2D and 3D data that requires the development of new tools for modelling and managing the archive.
... Innovision 3D, used our portable Biris system to record a section of the Mayan Hieroglyphic S... more ... Innovision 3D, used our portable Biris system to record a section of the Mayan Hieroglyphic Stairway in the Peabody Museum of Archaeology and Ethnology ... The objective was to digitize the Peabody's section of the Stairway and to prepare a 3D digital model (Figure 4). ...
This paper presents the most up-to-date experimental results obtained during the integration of a... more This paper presents the most up-to-date experimental results obtained during the integration of a 3D Laser Scanner Tracking System and the current Space Vision System used by NASA. Half scale models of modules of the Space Station Freedom have been built for this demonstration and comparison between the current method using video cameras and the Laser Scanner System are presented. The variable resolution laser scanner can track, in real time, targets and geometrical features of an object. The Laser Scanner System uses two high-speed galvanometers and a collimated laser beam to address individual targets on the object. Very high-resolution images and excellent tracking accuracy are obtained using Lissajous figures that provide high pointing accuracy of a laser beam. The prototype automatically searches and tracks, in 3D, targets attached to the object. The locations of the centroid of the detected targets are fed directly into the existing photosolution and attitude control modules of the Space Vision System.
Archaeology is emerging as one of the key areas of applications for laser range imaging. This par... more Archaeology is emerging as one of the key areas of applications for laser range imaging. This particular context imposes a number of specific constraints on the design and operations of range sensors. In this paper, we discuss some of the issues in designing and using laser range sensor systems for archaeology. Results obtained on remote archaeological sites will serve to illustrate these considerations.
We present the procedure and technologies used to modelling of the Erechtheion at the Acropolis i... more We present the procedure and technologies used to modelling of the Erechtheion at the Acropolis in Athens, a large complex structure with many challenges to data acquisition, processing, and visualisation. We used two scanners, one for medium range highresolution coverage (1-5 mm lateral data spacing) and one long-range scanner to capture some top sections occluded from the first scanner. We also used high-resolution digital images for image-based reconstruction using Photogrammetric and image matching techniques and for texture mapping. We focus in this paper on the geometric reconstruction from the range sensors. Several issues had to be addressed. Our system must be able to work with data obtained at different resolutions and accuracies and acquired from any viewpoint. The marble surfaces were of different age from one part to another due to decades of restoration. This resulted in different reflectance properties and apparent laser penetration that varied from area to area. Another problem resulted from the huge amount of data. The billions of generated 3D points by all sensors are currently beyond the processing capabilities of commercially available software or hardware. Reducing the data to a manageable size without losing important details had to be addressed.
Geometrical tracking and pose estimation using the homogeneous UVW inverse spherical coordinate s... more Geometrical tracking and pose estimation using the homogeneous UVW inverse spherical coordinate system, directly from range data obtained from a triangulation based range sensor, are demonstrated. The method is shown to be more accurate, reliable, and computationally faster than using the more conventional XYZ Cartesian coordinate system. This is presented through a practical application, by comparing the accuracy and resolution of a 3D laser scanner prototype that geometrically tracks and computes the relative pose of objects in 3D space. The system uses real-time geometrical surface fitting and intensity processing for the detection and tracking of planar targets on an object. A dual-axis laser scanner is used for this demonstration that combines optical triangulation, Lissajous scanning patterns, geometrical tracking, and photogrammetry (spatial resection), to calculate the relative pose of objects in the 3D space.
Isprs Journal of Photogrammetry and Remote Sensing, 2000
This paper summarises the results achieved from a number of laser scanning experiments performed ... more This paper summarises the results achieved from a number of laser scanning experiments performed in our laboratories and on remote sites. The potential of this technology for imaging applications and as an input to virtualised reality environments is discussed. Parameters to be considered for this type of activity are related to the design of laser scanners with adequate depth of field, image resolution, shape reproduction fidelity, registered colour information, robustness to ambient light interference and scanning strategies. The first case reviewed is an application geared towards improving access to art collections belonging to museums. A number of digital 3D models acquired in Italy in 1997-1998 are presented, e.g.
A portable digital 3D imaging system based on laser triangulation was designed for the accurate d... more A portable digital 3D imaging system based on laser triangulation was designed for the accurate documentation of environments and objects located in remote sites. Cultural heritage and industrial applications are among the best candidates to benefit from this new technology. This paper focuses on such aspects as the acquisition, display, calibration/verification, and especially on model building. These aspects were all optimized to create a versatile system that is truly portable, i.e. hand portable to a remote site. Emphasis is placed on accuracy verification and monitoring which are critical factors for obtaining high-quality reconstruction of 3D models from multiple range images. A summary of the experimental results acquired at a number of sites in Italy is presented in this paper
Journal of Visualization and Computer Animation, 2003
This paper presents the project &... more This paper presents the project "Development of Geographic Information Systems at the Acropolis of Athens", financed by the European Union and the Government of Greece. The Acropolis of Athens is one of the major archaeological sites world-wide included in the UNESCO World Heritage list. The project started in June 2007 and will finish at the end of 2008. The paper
Optical Engineering, 1992
A video rate laser range finder based on the autosynchronized scanning approach is presented. The... more A video rate laser range finder based on the autosynchronized scanning approach is presented. The range camera simultaneously provides range and intensity information of a scene in EIA- RS-170 format. A spatial resolution of 420 horizontal lines each having 512 pixels was achieved at a rate of 30 images per second. A wide dynamic range in intensity (16 bits) coupled with drift compensation allows this sensor to achieve a range resolution of 8 bits. The volume of view is 50 X 50 X 50 mm.
Applied Optics, 1991
A fast, range imaging, eye-safe laser scanner which uses a synchronized scanning geometry is desc... more A fast, range imaging, eye-safe laser scanner which uses a synchronized scanning geometry is described. The device operates at a 1.5-microm wavelength and incorporates an Er doped fiber laser as well as an InGaAs position sensitive detector. Factors influencing device performances are presented along with range images obtained at 1.5 microm.
This paper discuses the development of a short wavelength infrared laser ranging scanner system a... more This paper discuses the development of a short wavelength infrared laser ranging scanner system at the Canadian Space Agency in cooperation with the National Research Council Canada. A laser source at 1.54 micrometers wavelength is chosen for its relatively eye-safe property. The scanner system is to be considered for use as a space vision system for applications such as robot
An important application of laser range sensing is found in the 3D scanning and modelling of heri... more An important application of laser range sensing is found in the 3D scanning and modelling of heritage collections, and of sculptures in particular. Since a significant proportion of the statues in the world's museums is composed of marble, the optical properties of this material under laser range sensing need to be understood. Marble's translucency and heterogeneous structure produce significant bias and increased noise in the geometric measurements. Experiments on a sample of Carrara Statuario marble highlight the relationship between the laser spot diameter and the estimated noise levels in the geometric measurements. A bias in the depth measurement is also observed. These phenomena are believed to result from scattering on the surface of small crystals at or near the surface.
This work is part of the project "Development of Geographic Information Systems at the Acropolis ... more This work is part of the project "Development of Geographic Information Systems at the Acropolis of Athens". Within this project one of the aims is the generation of a textured, high-resolution, accurate 3D model of the Erechtheion and a realistic computer animation. For most parts, we used a medium-range time-of-flight (TOF) phase-based laser scanner with minimum lateral data spacing of 1 mm and depth uncertainty of 0.2 mm. We also used high-resolution digital images for image-based reconstruction on some parts and for texture mapping. We present data capture, processing, and model generation techniques with emphasis on the encountered problems and solutions when dealing with a large complex structure, huge datasets, and field work under time constraints and challenging conditions. The experience gained, and the tools adapted for some tasks, will be valuable for other large-scale 3D modelling projects.
As electronic documents are becoming more and more popular, variety of objects, including 2D and ... more As electronic documents are becoming more and more popular, variety of objects, including 2D and 3D objects such as articles, books and 3D-shapes, can be easily contained in a document. Conventional systems cannot capture these objects as a 3D form. We developed a new image capturing system with 3D information for deskwork. It is an assemblage of a normal digital camera and its docking station designed for easy operation. The docking station swings the attached camera tilting step by step. Within a few steps, it covers the whole object automatically. Then each frame is combined together into one complete image with full resolution. In order to get precise 3D structure, stripe patterns are projected by a modified flash light attached on the camera. The resolution rises by means of the swing to be slipped the patterns on the object. Using the obtained 3D data we can reconstruct a correct image from a splay surface image such as a book. Experimental Results of image mosaicing and 3D reconstruction shows that the system is practical.
The Grotta dei Cervi is a complex and fragile Neolithic cave where human presence left a large nu... more The Grotta dei Cervi is a complex and fragile Neolithic cave where human presence left a large number of unique pictographs and petroglyphs. Detailed documentation necessitates recording it at different levels of details or spatial resolutions. A general approach would entail a combination of 3D data from different 3D sensors and information from different sources in order to meet set resolution targets. We used a prototype multi-resolution 3D laser imaging scanner that allowed acquiring the shape information of the three main chambers with a spatial resolution that improves with shorter standoffs. The system can record 3D data at a camera-to-object distance which ranges from 0.5 m to 10 m. At a standoff of 0.75 m, it provides a depth uncertainty of 0.08 mm and an optical lateral resolution of 0.2 mm on actual rock surfaces. This paper presents the project and the results obtained. The 10-day long visit into the Grotto generated more that 100 GB of 2D and 3D data that requires the development of new tools for modelling and managing the archive.
... Innovision 3D, used our portable Biris system to record a section of the Mayan Hieroglyphic S... more ... Innovision 3D, used our portable Biris system to record a section of the Mayan Hieroglyphic Stairway in the Peabody Museum of Archaeology and Ethnology ... The objective was to digitize the Peabody's section of the Stairway and to prepare a 3D digital model (Figure 4). ...
This paper presents the most up-to-date experimental results obtained during the integration of a... more This paper presents the most up-to-date experimental results obtained during the integration of a 3D Laser Scanner Tracking System and the current Space Vision System used by NASA. Half scale models of modules of the Space Station Freedom have been built for this demonstration and comparison between the current method using video cameras and the Laser Scanner System are presented. The variable resolution laser scanner can track, in real time, targets and geometrical features of an object. The Laser Scanner System uses two high-speed galvanometers and a collimated laser beam to address individual targets on the object. Very high-resolution images and excellent tracking accuracy are obtained using Lissajous figures that provide high pointing accuracy of a laser beam. The prototype automatically searches and tracks, in 3D, targets attached to the object. The locations of the centroid of the detected targets are fed directly into the existing photosolution and attitude control modules of the Space Vision System.
Archaeology is emerging as one of the key areas of applications for laser range imaging. This par... more Archaeology is emerging as one of the key areas of applications for laser range imaging. This particular context imposes a number of specific constraints on the design and operations of range sensors. In this paper, we discuss some of the issues in designing and using laser range sensor systems for archaeology. Results obtained on remote archaeological sites will serve to illustrate these considerations.
We present the procedure and technologies used to modelling of the Erechtheion at the Acropolis i... more We present the procedure and technologies used to modelling of the Erechtheion at the Acropolis in Athens, a large complex structure with many challenges to data acquisition, processing, and visualisation. We used two scanners, one for medium range highresolution coverage (1-5 mm lateral data spacing) and one long-range scanner to capture some top sections occluded from the first scanner. We also used high-resolution digital images for image-based reconstruction using Photogrammetric and image matching techniques and for texture mapping. We focus in this paper on the geometric reconstruction from the range sensors. Several issues had to be addressed. Our system must be able to work with data obtained at different resolutions and accuracies and acquired from any viewpoint. The marble surfaces were of different age from one part to another due to decades of restoration. This resulted in different reflectance properties and apparent laser penetration that varied from area to area. Another problem resulted from the huge amount of data. The billions of generated 3D points by all sensors are currently beyond the processing capabilities of commercially available software or hardware. Reducing the data to a manageable size without losing important details had to be addressed.
Geometrical tracking and pose estimation using the homogeneous UVW inverse spherical coordinate s... more Geometrical tracking and pose estimation using the homogeneous UVW inverse spherical coordinate system, directly from range data obtained from a triangulation based range sensor, are demonstrated. The method is shown to be more accurate, reliable, and computationally faster than using the more conventional XYZ Cartesian coordinate system. This is presented through a practical application, by comparing the accuracy and resolution of a 3D laser scanner prototype that geometrically tracks and computes the relative pose of objects in 3D space. The system uses real-time geometrical surface fitting and intensity processing for the detection and tracking of planar targets on an object. A dual-axis laser scanner is used for this demonstration that combines optical triangulation, Lissajous scanning patterns, geometrical tracking, and photogrammetry (spatial resection), to calculate the relative pose of objects in the 3D space.
Isprs Journal of Photogrammetry and Remote Sensing, 2000
This paper summarises the results achieved from a number of laser scanning experiments performed ... more This paper summarises the results achieved from a number of laser scanning experiments performed in our laboratories and on remote sites. The potential of this technology for imaging applications and as an input to virtualised reality environments is discussed. Parameters to be considered for this type of activity are related to the design of laser scanners with adequate depth of field, image resolution, shape reproduction fidelity, registered colour information, robustness to ambient light interference and scanning strategies. The first case reviewed is an application geared towards improving access to art collections belonging to museums. A number of digital 3D models acquired in Italy in 1997-1998 are presented, e.g.