CS 194-26 Project 4A

Image Warping and Mosaicing

Angela Xu

Overview

For this project, I took some images around my apartment at different angles to stitch together into mosaics!

Shooting the Pictures

I made sure to shoot pictures with overlap, and tried to keep exposure consistent.

Here is one set of example images!

Recovering Homographies

To solve for the homography matrix, a 3x3 matrix with 8 degrees of freedom, I defined 8 correspondence point pairs (p', p), and solved for p’=Hp.

Here is an example of correspondence points:

Warping the Images and Image Rectification

Now we can apply the homography matrix to warp our images! As a sanity check, I first tried to rectify a picture frame.

It works! Now, I will be able to warp the other images.

Blending images into a mosaic

Using the homography matrix and my warping function, I stitched together three sets of images. I first found the homography matrix between left and right, then warped the right side image adding padding, and finally combined the images together, averaging values in the overlapping areas!

A horizontal one!

What I learned

In this project, I learned how panoramic pictures are created! I also found how important precision is when choosing correspondence points, as slight differences can really affect how images line up (this is evident in some of my results, because I could not perfectly select points in ginput). This has been very fun!