red green blue imaging topological radar
DESCRIPTION
This is an innovative 3D laser scanner, capable to acquire, at the same time and for each point, structure and color of the target, all by using three different laser sources.TRANSCRIPT
Authors: M. Guarneri, L. Bartolini, G. Fornetti, M. Ferri De Collibus, M. Francucci, E. Paglia, R. Ricci
Ente per le Nuove tecnologie, l'Energia e l'Ambiente
Co-Authors: J. Kolar, I. Nemec, M. Strlic
Massimiliano Guarneri – [email protected]
What will talk about
Introduction to RGB - Imaging Topological Radar Calibration methods and problems concerning
laser instability for long time-acquisitions Color measurement and color perception ITR Tools: software suite for collecting,
manipulating and inspecting RGB-ITR data Hrastovljie: first concrete result obtained by
RGB-ITR in monitoring and cataloguing fine arts Future developments Conclusions
Massimiliano Guarneri – [email protected]
Introduction to RGB-ITR
Optical head
Scanning system
Electronic system
Dichroic filter
Dichroic filter
* Here lasers are divided only for clarifying that
we are investigating the scene with 3 different laser sources
*
Massimiliano Guarneri – [email protected]
Ferrula vs dichroic filter
Ferrula features
Three separated laser beams (6 mrad among the red beam)
No power loss outside ferrula
Three RGB layers has to be registered via software
Suitable in a range of 15-35m
Dichroic filter features
Three superimposed laser beams
Power loss outside dichroic filter (about 60%)
Three RGB layers automatically registered
Suitable in a range of 3-15m
Massimiliano Guarneri – [email protected]
Calibration methods
During scanning process the ITR system uses white calibrated target for registering RGB space with the same reference point.
After Hrastovlje we introduced a new calibration method so to eliminate laser sources instability: special calibrated target are acquired every one hour.
Massimiliano Guarneri – [email protected]
Color measurement and color perception
RGB-ITR
Color measurement
Calibrated laser sources
Discriminate lambertian and back reflected component
Color perception
Acquired data free from external
light sources
Software algorithms
Massimiliano Guarneri – [email protected]
ITR Tools
ITR Tools
itrScanSytem PLY VieweritrAnalyzer
2D software (Photoshop, Paint
Shop Pro, Gimp,…)
3D software (Rapidform, Maya, Blender, Rhino,…)
RGB-ITR data manipulation and
inspection
Massimiliano Guarneri – [email protected]
Results obtained in Hrastovlje
Cerkev sv Trojica’s historySmall XII sec. (and later) Romanic church, was fortified against Turkish advance. Vaults, apse and walls were painted by Janez iz Kastva at the end of XV sec.
Massimiliano Guarneri – [email protected]
Our purposes
Due to the Italy-Slovenia collaboration, a 3D color digitalization of the most significative parts of the church was made for:Monitoring church structureMonitoring church’s paintingsDemonstrating that RGB-ITR images can be used for cataloguing cultural heritage
Massimiliano Guarneri – [email protected]
RGB-ITR parameters set in the church
* Due to a compromise with the available time, we set a resolution 4 times bigger than the real ITR resolution.
Massimiliano Guarneri – [email protected]
Mesh structure
Regular structure of the wireframe obtained by ITR data.
ITR mesh can be easily animated (i.e. structure stress simulation).
Mesh decimated of 90%
Massimiliano Guarneri – [email protected]
Mesh structure
Regular structure of the wireframe obtained by ITR data.
ITR mesh can be easily animated (i.e. structure stress simulation).
Morphological data are completely connected with color information – UV coords implicitly given.
Color information are not affected by external light sources.
Massimiliano Guarneri – [email protected]
Future developments
The next step will be the introduction of polariser for discriminating lambertian (which is color responsible) from back reflected component (which strongly depends on surface).
Strongest calibration method, so to avoid laser sources instabilities, will be introduced. Moreover a better white calibration at different distances will be permitted.
Massimiliano Guarneri – [email protected]
Conclusions
With the same technique introduced by ITR systems, an underwater 3D laser scanner is under investigation. Presently the developed prototype uses a monochromatic laser source and is able to acquire objects up to 3m with a resolution of 0.5 mm
