June 10, 2013 Presented by Joshua Vallecillos Supervised By Christine Wittich, Ph.D. Student, Structural Engineering

 Precise calibrations are needed in many computer vision applications  Use of the Jacobian matrix was implemented  Objective: Undistort GOPro Videos specific for shake table experiments

 Motion Tracking  3D Reconstruction  Mimic Seismic effects on statues

 Different Types of Distortions ◦ Skew -non squareness of Pixels ◦ Barrel Distortion – Spherical View ◦ Pincushion Effect- Bow inwards Grid Shows Barrel Distortion

 Use of a 30mm checker patterned grid with a 5x7 dimension.  Video Recording and Capturing of different angles of grid  Camera Specifications: Model: GOPRO Hero3 Black ◦ For GOPR0001: Camera Setting: Wide FOV 1080p (60 frames per second) ◦ For GOPR4561: Camera Setting: Narrow FOV 720p (120 frames per second)

Steps TakenImages  Preliminary Stage  Reading Images  Extracting Grid Corners  Main Calibration Stage  Recalibration Calibration Toolbox, Extraction of the Grid Corners Step by Step, World Centered View and Analyse Error

 Processing Images through Matlab  Extraction Process ◦ Extensive amount of time ◦ Reiteration of Images

PR0001  Focal Length: fc = [ ] ± [ ]  Principal point: cc = [ ] ± [ ]  Skew: alpha_c = [ ] ± [ ] => angle of pixel axes = ± degrees  Distortion: kc = [ ] ± [ ]  Pixel error: err = [ ]  PR4561  Focal Length: fc = [ ] ± [ ]  Principal point: cc = [ ] ± [ ]  Skew: alpha_c = [ ] ± [ ] => angle of pixel axes = ± degrees  Distortion: kc = [ ] ± [ ]  Pixel error: err = [ ]  Note: The numerical errors are approximately three times the standard deviations (for reference).

 Success!  Hands on Experience  Motion Tracking Before and after undistortion