Image-based Modeling and Rendering

 Assignment 2: View Transformation

 Li Zhang
 Ph.D. Candidate of Robotics
 School of Computer Science
 Carnegie Mellon University

In this assignment, i implement the warp equation given in the Ph.D. thesis by Leonard McMillan. The results are as follows:

This is the front view of my scanned face.

This is rendered from left side.

This is rendered from left bottom corner.

This is rendered from bottom side.

This is rendered from right bottom corner.

This is rendered from right side.

This is rendered from right top corner.

This is rendered from top side.

This is rendered from left top corner.

These two are render from left and right profile view.

The noise on my nose might be caused by the inaccurate depth informaion.

I wrote the codes using Visual C++6.0. The executable file warp.exe is under ./asst2/warp/Release of my course directory. The codes under ./asst2/warp/mystuff are kernal warping codes. The rest files under ./warp are the UI codes generated by Visual C++. The user could rotate around the object by pressing left mouse button down and dragging it. The user could also come closer, go far away, zoom in, zoom out, or take a picture by simply clicking a certain button on the frame window. The speed of my program is REAL TIME. The drawback is that i use the ascii file generated by Paul's codes.
I used McMillan's method to determine visibility. I treated each pixel as a square to fill hole. To be more specific,
if (x,y) (x+1,y) (x,y+1) (x+1,y+1) are four pixels with colors c0, c1, c2, c3, and their corresponding positions in new image plane are (u0,v0) (u1,v1) (u2,v2) (u3,v3), I use the following codes to fill the hole:

//disable the depth value and determine visibility by the order of scaning


// begin scaning,
// for each pixel, get new position by using warping equation;
// and using incremental method to accelerate the speed.

//then fill hole as follows:
glColor3ubv(c0); glVertex2d(u0,v0);
glColor3ubv(c1); glVertex2d(u1,v1);
glColor3ubv(c2); glVertex2d(u2,v2);
glColor3ubv(c3); glVertex2d(u3,v3);