Project 4 Part 1: Image warping and mosaicing!

CS194-26 Fall 2021 | Rio Hayakawa


Introduction

In this project, we will be implementing an auto panoramic mosaic stitcher using multiple images shot from the same location. In this part, we define corresponding points in each of the images and calculate a homography matrix to warp the images to one another to align and stich them.

Shoot and Digitize Images

Images for stitching:

Wurster Left Wurster Right

Images for rectifying:

Recover Homographies

In order to get the transformation matrix between the images, we must recover the homography matrix H as below.

We can do this by solving a linear system set up using the corresponding points between the images as below.

Warp the Images

Using the parameters of homography, we warp the left image according to the corresponding points of the right image.

Before Warp After Warp

Image Rectification

We can demonstrate that the warping is working by warping an object that we know is a rectangle and assigning the corresponding points to be such.

Before Rectifying After Rectifying
Before Rectifying After Rectifying

Blending the images into a mosaic

Conclusion

The coolest thing I learned was that we can make out patterns and text from an image of a rectangular object just by using a homography and rectification. It’s fun that we can stretch out a certain perspective of an image to make it look like we are looking at the object straight on.