Francois Blais - Academia.edu (original) (raw)

Papers by Francois Blais

Research paper thumbnail of <title>Control Of Low Inertia Galvanometers For High Precision Laser Scanning Systems</title>

Optical Engineering, 1988

Research paper thumbnail of <title>Digital three-dimensional imaging in the infrared at the National Research Council of Canada</title>

Infrared Technology XX, 1994

Research paper thumbnail of <title>Range-image segmentation, free-space determination, and position estimate for a mobile vehicle</title>

Mobile Robots VII, 1993

ABSTRACT

Research paper thumbnail of <title>Comparative evaluation of the performance of passive and active 3D vision systems</title>

Digital Photogrammetry and Remote Sensing '95, 1995

Automated digital photogrammetric systems are considered to be passive three-dimensional vision s... more Automated digital photogrammetric systems are considered to be passive three-dimensional vision systems since they obtain object coordinates from only the information contained in intensity images. Active 3-D vision systems, such as laser scanners and structured light systems obtain the object coordinates from external information such as scanning angle, time of flight, or shape of projected patterns. Passive systems provide high accuracy on well defined features, such as targets and edges however, unmarked surfaces are hard to measure. These systems may also be difficult to automate in unstructured environments since they are highly affected by the ambient light. Active systems provide their own illumination and the features to be measured so they can easily measure surfaces in most environments. However, they have difficulties with varying surface finish or sharp discontinuities such as edges. Therefore each type of sensor is more suited for a specific type of objects and features, and they are often complementary. This paper compares the measurement accuracy, as applied to various type of features, of some technologically-different 3-D vision systems: photogrammetry-based (passive) systems, a laser scanning system (active), and a range sensor using a mask with two apertures and structured light (active).

Research paper thumbnail of <title>Eye-safe imaging and tracking laser scanner system for space applications</title>

Laser Radar Technology and Applications, 1996

Research paper thumbnail of <title>Differential inspection of shapes using optical 3D measurements</title>

Optical 3D Measurement Techniques II: Applications in Inspection, Quality Control, and Robotics, 1994

ABSTRACT

Research paper thumbnail of <title>3D imaging from theory to practice: the Mona Lisa story</title>

Current Developments in Lens Design and Optical Engineering IX, 2008

The warped poplar panel and the technique developed by Leonardo to paint the Mona Lisa present a ... more The warped poplar panel and the technique developed by Leonardo to paint the Mona Lisa present a unique research and engineering challenge for the design of a complete optical 3D imaging system. This paper discusses the solution developed to precisely measure in 3D the world most famous painting despite its highly contrasted paint surface and reflective varnish. The discussion focuses on the opto-mechanical design and the complete portable 3D imaging system used for this unique occasion. The challenges associated with obtaining 3D color images at a resolution of 0.05 mm and a depth precision of 0.01 mm are illustrated by exploring the virtual 3D model of the Mona Lisa.

Research paper thumbnail of Intelligent variable-resolution laser scanner for the space vision system

A newly developed laser range scanner which can identify and locate targets attached to a satelli... more A newly developed laser range scanner which can identify and locate targets attached to a satellite is described. This identification can be performed even with the sun shining directly into the sensor. The sensor makes use of two high-speed galvanometers to address individual pixels in a high-resolution large field of view. Specular reflections and background illumination problems are eliminated by

Research paper thumbnail of Datagraphy: The Final Frontier in Communications

Research paper thumbnail of Calibration of an anamorphic laser-based 3D range sensor

Storage and Retrieval for Image and Video Databases, 1997

This paper describes the parameters and method used to calibrate an anamorphic lens specially des... more This paper describes the parameters and method used to calibrate an anamorphic lens specially designed for a 3D triangulation based laser range sensor. It expands the more `conventional' spherical lens calibration technique that has been developed in photogrammetry to include the extra distortions introduced by the strong astigmatism and by the different optical principal planes of the lens of the

Research paper thumbnail of Range Error Analysis of an Integrated Time-of-Flight, Triangulation, and Photogrammetry 3D Laser Scanning System

Storage and Retrieval for Image and Video Databases, 2000

A 3-D laser tracking scanner system analysis focusing on immunity to ambient sunlight and geometr... more A 3-D laser tracking scanner system analysis focusing on immunity to ambient sunlight and geometrical resolution and accuracyis presented in the context of a space application. The main goal of this development is to provide a robust sensor to assist in theassembly of the Space Station. This 3-D laser scanner system can be used in imagery or in tracking modes,

Research paper thumbnail of Application of the BIRIS range sensor for wood volume measurement

Research paper thumbnail of Real-time numerical peak detector

Research paper thumbnail of Integration of a tracking laser range camera with the photogrammetry-based space vision system

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.

Research paper thumbnail of Three-dimensional tracking and imaging laser scanner for space operations

Proceedings of SPIE - The International Society for Optical Engineering

ABSTRACT This paper presents the development of a laser range scanner (LARS) as a three-dimension... more ABSTRACT This paper presents the development of a laser range scanner (LARS) as a three-dimensional sensor for space applications. The scanner is a versatile system capable of doing surface imaging, target ranging and tracking. It is capable of short range (0.5 m to 20 m) and long range (20 m to 10 km) sensing using triangulation and time-of-flight (TOF) methods respectively. At short range (1 m), the resolution is sub-millimeter and drops gradually with distance (2 cm at 10 m). For long range, the TOF provides a constant resolution of plus or minus 3 cm, independent of range. The LARS could complement the existing Canadian Space Vision System (CSVS) for robotic manipulation. As an active vision system, the LARS is immune to sunlight and adverse lighting; this is a major advantage over the CSVS, as outlined in this paper. The LARS could also replace existing radar systems used for rendezvous and docking. There are clear advantages of an optical system over a microwave radar in terms of size, mass, power and precision. Equipped with two high-speed galvanometers, the laser can be steered to address any point in a 30 degree X 30 degree field of view. The scanning can be continuous (raster scan, Lissajous) or direct (random). This gives the scanner the ability to register high-resolution 3D images of range and intensity (up to 4000 X 4000 pixels) and to perform point target tracking as well as object recognition and geometrical tracking. The imaging capability of the scanner using an eye-safe laser is demonstrated. An efficient fiber laser delivers 60 mW of CW or 3 (mu) J pulses at 20 kHz for TOF operation. Implementation of search and track of multiple targets is also demonstrated. For a single target, refresh rates up to 137 Hz is possible. Considerations for space qualification of the scanner are discussed. Typical space operations, such as docking, object attitude tracking, and inspections are described.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Research paper thumbnail of Recent Developments in 3D Multi-modal Laser Imaging Applied to Cultural Heritage

Machine Vision and Applications

This paper proposes a novel multi-modal three-dimensional (3D) laser scanning system that combine... more This paper proposes a novel multi-modal three-dimensional (3D) laser scanning system that combines high-accuracy 3Dlaser imaging, very high-resolution perspective color projection, and on-site geometric calibration of the intrinsic and extrinsic parameters. Motion compensation directly from the range measurements using ICP and a 6-DOF self-built model tracking is also used to eliminate the need for stable mechanical structures and external positioning sensors. We show that scanner performances, modeling, and visualization are intimately linked and must be considered as an integral part of the modeling chain. This is particularly important in the field of heritage where the acquisition must adapt to the environment. Equations and charts are presented to compute the optimum color camera and laser scanner configuration for a given 3D modeling application in terms of camera settings such as optimum lens aperture, focal length, optimum range, and total range depth. These equations are ge...

Research paper thumbnail of Proposed procedure for a distance protocol in support of ASTM-E57 standards activities on 3D imaging

Proceedings of SPIE - The International Society for Optical Engineering

The performance of 3D Imaging Systems needs to be evaluated using a common terminology and test p... more The performance of 3D Imaging Systems needs to be evaluated using a common terminology and test procedures. This evaluation is necessary because three-dimensional imaging systems are measuring instruments and the spatial coordinates they provide are only estimates of the 3D surfaces being sampled. These coordinates need to be completed by a quantitative statement about their uncertainty to be meaningful. The statement of uncertainty is based on comparisons with standards traceable to the national units of length (SI units). We describe and present experimental results of a procedure to evaluate distance measurement uncertainty of medium range laser scanners (range between 2-100m). The procedure is based on the evaluation of Point-to-Point distance errors using custom made Reference Test Object (RTO) and a certified 3D laser tracker as a reference. This work is proposed as a possible protocol to the American Society for Testing and Materials (ASTM)-E57.02 3D Imaging Systems standards...

Research paper thumbnail of <title>A Very Compact Real Time 3-D Range Sensor For Mobile Robot Applications</title>

Mobile Robots III, 1989

ABSTRACT

Research paper thumbnail of <title>Practical Considerations For A Design Of A High Precision 3-D Laser Scanner System</title>

Optomechanical and Electro-Optical Design of Industrial Systems, 1988

Research paper thumbnail of NEW DEVELOPMENTS IN 3D LASER SCANNERS: FROM STATIC TO DYNAMIC MULTI-MODAL SYSTEMS

This paper reviews some of the most popular 3D laser scanning methods available today and describ... more This paper reviews some of the most popular 3D laser scanning methods available today and describes recent research done in the field of multi -modal 3D laser systems, including 3D color laser, perspective color projection on complex 3D surfaces, some hand-held techniques, and introduces our most recent work to create a high-resolution (sub-millimeters) medium volume (m3) truly hand-held system.

Research paper thumbnail of <title>Control Of Low Inertia Galvanometers For High Precision Laser Scanning Systems</title>

Optical Engineering, 1988

Research paper thumbnail of <title>Digital three-dimensional imaging in the infrared at the National Research Council of Canada</title>

Infrared Technology XX, 1994

Research paper thumbnail of <title>Range-image segmentation, free-space determination, and position estimate for a mobile vehicle</title>

Mobile Robots VII, 1993

ABSTRACT

Research paper thumbnail of <title>Comparative evaluation of the performance of passive and active 3D vision systems</title>

Digital Photogrammetry and Remote Sensing '95, 1995

Automated digital photogrammetric systems are considered to be passive three-dimensional vision s... more Automated digital photogrammetric systems are considered to be passive three-dimensional vision systems since they obtain object coordinates from only the information contained in intensity images. Active 3-D vision systems, such as laser scanners and structured light systems obtain the object coordinates from external information such as scanning angle, time of flight, or shape of projected patterns. Passive systems provide high accuracy on well defined features, such as targets and edges however, unmarked surfaces are hard to measure. These systems may also be difficult to automate in unstructured environments since they are highly affected by the ambient light. Active systems provide their own illumination and the features to be measured so they can easily measure surfaces in most environments. However, they have difficulties with varying surface finish or sharp discontinuities such as edges. Therefore each type of sensor is more suited for a specific type of objects and features, and they are often complementary. This paper compares the measurement accuracy, as applied to various type of features, of some technologically-different 3-D vision systems: photogrammetry-based (passive) systems, a laser scanning system (active), and a range sensor using a mask with two apertures and structured light (active).

Research paper thumbnail of <title>Eye-safe imaging and tracking laser scanner system for space applications</title>

Laser Radar Technology and Applications, 1996

Research paper thumbnail of <title>Differential inspection of shapes using optical 3D measurements</title>

Optical 3D Measurement Techniques II: Applications in Inspection, Quality Control, and Robotics, 1994

ABSTRACT

Research paper thumbnail of <title>3D imaging from theory to practice: the Mona Lisa story</title>

Current Developments in Lens Design and Optical Engineering IX, 2008

The warped poplar panel and the technique developed by Leonardo to paint the Mona Lisa present a ... more The warped poplar panel and the technique developed by Leonardo to paint the Mona Lisa present a unique research and engineering challenge for the design of a complete optical 3D imaging system. This paper discusses the solution developed to precisely measure in 3D the world most famous painting despite its highly contrasted paint surface and reflective varnish. The discussion focuses on the opto-mechanical design and the complete portable 3D imaging system used for this unique occasion. The challenges associated with obtaining 3D color images at a resolution of 0.05 mm and a depth precision of 0.01 mm are illustrated by exploring the virtual 3D model of the Mona Lisa.

Research paper thumbnail of Intelligent variable-resolution laser scanner for the space vision system

A newly developed laser range scanner which can identify and locate targets attached to a satelli... more A newly developed laser range scanner which can identify and locate targets attached to a satellite is described. This identification can be performed even with the sun shining directly into the sensor. The sensor makes use of two high-speed galvanometers to address individual pixels in a high-resolution large field of view. Specular reflections and background illumination problems are eliminated by

Research paper thumbnail of Datagraphy: The Final Frontier in Communications

Research paper thumbnail of Calibration of an anamorphic laser-based 3D range sensor

Storage and Retrieval for Image and Video Databases, 1997

This paper describes the parameters and method used to calibrate an anamorphic lens specially des... more This paper describes the parameters and method used to calibrate an anamorphic lens specially designed for a 3D triangulation based laser range sensor. It expands the more `conventional' spherical lens calibration technique that has been developed in photogrammetry to include the extra distortions introduced by the strong astigmatism and by the different optical principal planes of the lens of the

Research paper thumbnail of Range Error Analysis of an Integrated Time-of-Flight, Triangulation, and Photogrammetry 3D Laser Scanning System

Storage and Retrieval for Image and Video Databases, 2000

A 3-D laser tracking scanner system analysis focusing on immunity to ambient sunlight and geometr... more A 3-D laser tracking scanner system analysis focusing on immunity to ambient sunlight and geometrical resolution and accuracyis presented in the context of a space application. The main goal of this development is to provide a robust sensor to assist in theassembly of the Space Station. This 3-D laser scanner system can be used in imagery or in tracking modes,

Research paper thumbnail of Application of the BIRIS range sensor for wood volume measurement

Research paper thumbnail of Real-time numerical peak detector

Research paper thumbnail of Integration of a tracking laser range camera with the photogrammetry-based space vision system

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.

Research paper thumbnail of Three-dimensional tracking and imaging laser scanner for space operations

Proceedings of SPIE - The International Society for Optical Engineering

ABSTRACT This paper presents the development of a laser range scanner (LARS) as a three-dimension... more ABSTRACT This paper presents the development of a laser range scanner (LARS) as a three-dimensional sensor for space applications. The scanner is a versatile system capable of doing surface imaging, target ranging and tracking. It is capable of short range (0.5 m to 20 m) and long range (20 m to 10 km) sensing using triangulation and time-of-flight (TOF) methods respectively. At short range (1 m), the resolution is sub-millimeter and drops gradually with distance (2 cm at 10 m). For long range, the TOF provides a constant resolution of plus or minus 3 cm, independent of range. The LARS could complement the existing Canadian Space Vision System (CSVS) for robotic manipulation. As an active vision system, the LARS is immune to sunlight and adverse lighting; this is a major advantage over the CSVS, as outlined in this paper. The LARS could also replace existing radar systems used for rendezvous and docking. There are clear advantages of an optical system over a microwave radar in terms of size, mass, power and precision. Equipped with two high-speed galvanometers, the laser can be steered to address any point in a 30 degree X 30 degree field of view. The scanning can be continuous (raster scan, Lissajous) or direct (random). This gives the scanner the ability to register high-resolution 3D images of range and intensity (up to 4000 X 4000 pixels) and to perform point target tracking as well as object recognition and geometrical tracking. The imaging capability of the scanner using an eye-safe laser is demonstrated. An efficient fiber laser delivers 60 mW of CW or 3 (mu) J pulses at 20 kHz for TOF operation. Implementation of search and track of multiple targets is also demonstrated. For a single target, refresh rates up to 137 Hz is possible. Considerations for space qualification of the scanner are discussed. Typical space operations, such as docking, object attitude tracking, and inspections are described.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Research paper thumbnail of Recent Developments in 3D Multi-modal Laser Imaging Applied to Cultural Heritage

Machine Vision and Applications

This paper proposes a novel multi-modal three-dimensional (3D) laser scanning system that combine... more This paper proposes a novel multi-modal three-dimensional (3D) laser scanning system that combines high-accuracy 3Dlaser imaging, very high-resolution perspective color projection, and on-site geometric calibration of the intrinsic and extrinsic parameters. Motion compensation directly from the range measurements using ICP and a 6-DOF self-built model tracking is also used to eliminate the need for stable mechanical structures and external positioning sensors. We show that scanner performances, modeling, and visualization are intimately linked and must be considered as an integral part of the modeling chain. This is particularly important in the field of heritage where the acquisition must adapt to the environment. Equations and charts are presented to compute the optimum color camera and laser scanner configuration for a given 3D modeling application in terms of camera settings such as optimum lens aperture, focal length, optimum range, and total range depth. These equations are ge...

Research paper thumbnail of Proposed procedure for a distance protocol in support of ASTM-E57 standards activities on 3D imaging

Proceedings of SPIE - The International Society for Optical Engineering

The performance of 3D Imaging Systems needs to be evaluated using a common terminology and test p... more The performance of 3D Imaging Systems needs to be evaluated using a common terminology and test procedures. This evaluation is necessary because three-dimensional imaging systems are measuring instruments and the spatial coordinates they provide are only estimates of the 3D surfaces being sampled. These coordinates need to be completed by a quantitative statement about their uncertainty to be meaningful. The statement of uncertainty is based on comparisons with standards traceable to the national units of length (SI units). We describe and present experimental results of a procedure to evaluate distance measurement uncertainty of medium range laser scanners (range between 2-100m). The procedure is based on the evaluation of Point-to-Point distance errors using custom made Reference Test Object (RTO) and a certified 3D laser tracker as a reference. This work is proposed as a possible protocol to the American Society for Testing and Materials (ASTM)-E57.02 3D Imaging Systems standards...

Research paper thumbnail of <title>A Very Compact Real Time 3-D Range Sensor For Mobile Robot Applications</title>

Mobile Robots III, 1989

ABSTRACT

Research paper thumbnail of <title>Practical Considerations For A Design Of A High Precision 3-D Laser Scanner System</title>

Optomechanical and Electro-Optical Design of Industrial Systems, 1988

Research paper thumbnail of NEW DEVELOPMENTS IN 3D LASER SCANNERS: FROM STATIC TO DYNAMIC MULTI-MODAL SYSTEMS

This paper reviews some of the most popular 3D laser scanning methods available today and describ... more This paper reviews some of the most popular 3D laser scanning methods available today and describes recent research done in the field of multi -modal 3D laser systems, including 3D color laser, perspective color projection on complex 3D surfaces, some hand-held techniques, and introduces our most recent work to create a high-resolution (sub-millimeters) medium volume (m3) truly hand-held system.