Last UpDate 13.11.2003 5:36 PM

 

 

 

 

THE MISSION OF MY RESEARCH

  My dream is to measure the entire surface of a 3D moving object (in a certain volume)
and to reproduce it in a virtual environment in order have a real-time measurement of its
deformation and its position.

 

 

 

Research Interests:

  Signal, image/video processing and communication, computer vision, medical imaging;

  Multi-dimensional scanning, 3D measurement and other multimedia applications;

  Camera calibration methods and Computational Geometry;

  Computer graphics/animation and image based rendering;

  Medical Imaging & Biomedical Instrument Development;

 


Past Research:

  Subpixel measurement of target displacement

  Optical Flow

  Stereo disparity

  Image filtering

 


Current Research:

3D Scanning of moving objects based on "one snap" FTP methods;

Fully Automated cameras calibrations methods;

  Chessboard grid calibration based on a double Radon Transform.

Colour Space Transformation;

 

  3D Scanning of moving objects based on "one snap" FTP methods

 

My Ph D project consists in designing a 3D scanner to perform surface measurement of moving objects.
The 3D scanners are gaining huge spreading in the market today, but the great majority of them can only scan surfaces of stationary objects.
The innovation of the project consists in extracting the surface skin of an object without imposing it to stop.

The calibration grid

The scanner

You will find here following some preliminary results:

               

             

          The otput with the texture

 

 

 

 

 

 

Click on The image to enlarge it !

 

The Vrml file of the output is about 19MB
even zipped it was to big to link here
,
If You need It please e-mail me

 
 

 

 Chessboard grid calibration based on a double Radon Transform

 

     The goal of this work was:

  Minimize the time needed to calibrate a 3D FTP Scanner

  automatizing the Calibration Process

  Create a robust algorithm

  insensitive to the aberration caused by the lenses
  insensitive to generic backgrounds



 

 

When the scanner is calibrated?

Camera & Projectors

- Intrinsic parameters:

o Focal length
o Principal point
o Skew coefficient (angle between the x and y pixel axes )
o Distortions (radial and tangential)

- Extrinsic parameters:

o Rotations
o Translations

 

 

 

Innovation of the method

Improvements

  It can extract corners even if the chessboard is partially occluded or if the corners are outside the image

  It can exclude all the corners which are not on the chessboard

 

 

The Double Radon Transform

 

   
                         

 

                       

 

                       

 
                         

 

The Klaus Kohlmann algorithm

  It consists in a 2D Hilbert transform

  Limit of the Algorithm
          applicable only in the range from - 5° to 5° rotations

 

 

                           

 

 

 

Combining the two algorithms potentialities

   

 

  In this case DRT is fundamental to give a good estimate of the reference frame connected to chessboard grid

 

 

                  

 

 

 

  Computing than a suitable prospective transform to obtain the edge of the grid be parallel to the axis image

 

 

 

  Than Klaus Kohlmann algorithm will give us the right estimation of the corners positions with subpixel Accuracy

 

                  

 

 

Example:

Click on the image to open the movie