Calibration of an anamorphic laser-based 3D range sensor (original) (raw)

Calibration of an anamorphic laser-based 3D range sensor

Videometrics V, 1997

This paper describes the parameters and method used to calibrate an anamorphic lens specially designed for a 3-D 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 anamorphic design. Experimental results using a prototype of the lens for the Biris range sensor are presented.

Photogrammetric calibration of the SwissRanger 3D range imaging sensor

Optical Sensors 2008, 2008

Many robotic and industrial systems require 3D range-sensing capabilities for mapping, localization, navigation, and obstacle avoidance. Laser-scanning systems that mechanically trace a range-sensing beam over a raster or similar pattern can produce highly accurate models but tend to be bulky and slow when acquiring a significant field of view at useful resolutions. Stereo cameras can provide video-rate range images over significant fields of view but tend to have difficulty with scenes containing low or confusing textures. A new generation of active light, time-of-flight range sensors use a 2D array of sensor elements to produce a 3D range image at video rates. These sensors pose unique calibration challenges, requiring both the usual calibration of lens distortion (intrinsic calibration) and calibration of the time-of-flight range measurement (3D calibration). This paper presents our application of a photogrammetric calibration approach using inexpensive printed optical targets and off-the-shelf software to solve both intrinsic and range calibrations for the MESA Imaging SwissRanger™ 3100 range imaging sensor. We further identify specific calibration issues stemming from this sensor's correlation of reflectivity with measured range.

Acquisition of consistent range data using local calibration

1994

This paper addresses two aspects of triangulationbased range sensors using structured laser light: calibration and measurements consistency. We present a direct calibration technique which does not require modelling any speci c sensor component or phenomena, therefore is not limited in accuracy by the inability to model error sources. We also introduce some consistency tests based on two-camera geometry which make it possible to acquire satisfactory range images of highly re ective surfaces with holes. Experimental results indicating the validity of the methods are reported.

Direct calibration and data consistency in 3-D laser scanning

1994

This paper addresses two aspects of triangulation-based range sensors using structured laser light: calibration and measurements consistency. We present a direct calibration technique which does not require modelling any specific sensor component or phenomena, therefore is not limited in accuracy by the inability to model error sources. We also sketch some consistency tests based on two-camera geometry which make it possible to acquire satisfactory range images of highly reflective surfaces with holes. Experimental results indicating the validity of the methods are reported.

Range calibration for terrestrial laser scanners and range cameras

Videometrics, Range Imaging, and Applications X, 2009

Range cameras and terrestrial laser scanners provide 3D geometric information by directly measuring the range from the sensor to the object. Calibration of the ranging component has not been studied systematically yet, and this paper provides a first overview. The proposed approaches differ in the object space features used for calibration, the calibration models themselves, and possibly required environmental conditions. A number of approaches are reviewed within this framework and discussed. For terrestrial laser scanners, improvement in accuracy by a factor up to two is typical, whereas range camera calibration still lacks a proper model, and large systematic errors typically remain.

Extrinsic Calibration of a Laser Galvanometric Setup and a Range Camera

Sensors

Currently, galvanometric scanning systems (like the one used in a scanning laser Doppler vibrometer) rely on a planar calibration procedure between a two-dimensional (2D) camera and the laser galvanometric scanning system to automatically aim a laser beam at a particular point on an object. In the case of nonplanar or moving objects, this calibration is not sufficiently accurate anymore. In this work, a three-dimensional (3D) calibration procedure that uses a 3D range sensor is proposed. The 3D calibration is valid for all types of objects and retains its accuracy when objects are moved between subsequent measurement campaigns. The proposed 3D calibration uses a Non-Perspective-n-Point (NPnP) problem solution. The 3D range sensor is used to calculate the position of the object under test relative to the laser galvanometric system. With this extrinsic calibration, the laser galvanometric scanning system can automatically aim a laser beam to this object. In experiments, the mean accuracy of aiming the laser beam on an object is below 10 mm for 95% of the measurements. This achieved accuracy is mainly determined by the accuracy and resolution of the 3D range sensor. The new calibration method is significantly better than the original 2D calibration method, which in our setup achieves errors below 68 mm for 95% of the measurements.

Calibration, Data Consistency and Model Acquisition with a 3-D Laser Striper

1998

We analyse the issues of calibration, stripe location and measurement consistency in low-cost, triangulation-based range sensors using structured laser light. We adopt a direct calibration technique which does not require modelling any speci c sensor component or phenomena, and therefore is not limited in accuracy by the inability to model error sources. We compare ve algorithms for determining the location of the stripe in the images with subpixel accuracy. We describe data consistency tests based on two-camera geometry, which make it possible to acquire satisfactory range images of highly re ective surfaces with holes. Finally, we sketch the use of our range sensor within an automatic system for 3-D model acquisition from multiple range images. Experimental results illustrating the various topics accuracy are reported and discussed.