CS194-26: Image Manipulation and Computational Photography

Programming Project #6: Image Warping and Mosaicing

Dennis Lee (cs194-26-acy)


Using homographies, we change the perspective of already taken images.

Image Rectifying

A homography can be used to transform a tilted image into a head-on version. Just define some points on the image, define the target as a rectangle, and have the transformation match those points up

Memorial Glade

East Asian Library

Source Rectangle

Target Rectangle

Professor Efros's Door


Failure Case

Squares too small

Image Mosaic

We can also transform one image into the perspective of another. Then we can stitch the images together using some method previously learned to create a mosaic or panorama.






Mount Tam



Mount Tam


Today I learned it's surprisingly annoying to define correspondences in landscape images, even by hand, since a lot of the features are rounded and getting a perfect selection is challenging. Even the slightest error can cause signficant distortions, unless you define way too many points.