1. Endoscope Exploration on Knee Surface 15-862 Computed Photography Final Project Chenyu Wu

2. Motivation Endoscope is widely used in minimally invasive surgery

3. Problem The size and distortion of endoscope images limit its use.

4. Our Goal Stitch the endoscope images onto a 3D surface to get a bigger view of the knee surface

5. Solution Calibration –Image: Correct the distortion –Camera: Get intrinsic parameters Map onto surface –Put trackers on the endoscope and bone –Compute the transformation between camera and bone –Texture mapping

6. Image Calibration Basic idea – warp! rectify! –Generate a set of checker board and grid images –Define the correspondences between original image and endoscope image –Compute Homograph for each corresponding images –Same endoscope, consider least square to get the best fit homograph

7. Test images (checkerboard)

8. Endoscope images (checkerboard)

9. Test images (grid)

10. Endoscope Images (grid)

11. Warp result

12. Camera Calibration Determine intrinsic parameters –Given a set of control points with known x,y,z and u,v –Least Square

13. Transformation between camera and bone Determine extrinsic parameters

14. Texture mapping Compute the transformation from image to bone (surface) Given each image, we can find the corresponding vertex and local triangles on the surface Warp!

15. References C. ARLOS. H. ENRIQUE. Q. UARTUCCI. F. ORSTER. C. LÉSIO. L. T. OZZI, “Toward 3d reconstruction of endoscope images using shape from shading”, Proceedings SIBGRAPI 2000, XIII Brazilian Symposium on Computer Graphics and Image Processing, Gramado, RS, pp. 90-96, October, 2000. C. Soler, M. Cani, A. Angelidis, “Hierarchical pattern mapping”, ACM Trans. On Graphics (TOG), 21(3): 673-680, 2002.