Measurement of 3-Dimensional Distal Femoral Surface Assessment
The objective of this project is to reconstruct the 3-dimensional (3-D) surface of femoral condyles using stereophotogrammetry. Images of femoral condyles with grid lines and 8 calibration markers are taken from different angles. The actual 3-dimensional coordinates (X,Y,Z) of 8 calibration markers are provided on another document (I sent it to you). The 3-dimensional surface of femoral condyles can be constructed using images taken from at least two angles or more based on the theoretical formula that was shown in the Lecture #10 (also sent to you). The following is the general procedure:
- Digitize images to obtain the local coordinates (x, y) of the calibration markers and grid intersection points on the surface of femoral condyles from individual images using Image J which can be downloaded fromhttp://rsbweb.nih.gov/ij/download.html.
- Use Matlab to calculate the 3-D coordinates of the grid intersection points on the surface of femoral condyles:
- Determine camera parameters for different angles (at least 2 angles) based on the local coordinates (x,y) and actual 3-dimensional coordinates of the calibration markers (at least 6 markers);
- Calculate the 3-D coordinates of the calibration markers using the theoretical method based on the camera parameters and then determine errors in 3 coordinate axes: error (%) = (calculated 3-D coordinate actual 3-D coordinate)/ actual 3-D coordinate *100 ;
- Determine the 3-D coordinates of the grid intersection points on the surface of femoral condyles (at least 180 points) using camera parameters.
- Reconstruct the 3-D surface of femoral condyles using Matlab, Pro-E, or other software.
The following components should be included in the report:
- Original images used in the project
- Matlab program
- Camera parameters
- Error calculation based on the 3D coordinate determination of calibration markers
- Data of 2-D digitization and 3-D reconstruction of the femoral surface
- Three-dimensional surface plot of the femoral condyles
The electronic copies of the report, Matlab program and 2-D digitization data are needed.
Important:
Comparison of the 3-D coordinates calculations between 3 combinations of two images (e.g., different images from angles or different numbers of images)