Project 4A: Image Warping and Mosaicing

CS 194-26: Intro. to Computer Vision & Computational Photography, Fa21

Doyoung Kim


Overview

  In the previous project, we have discovered how inverse warping can be used to transform an image using projections. In this project, we use projective transformation to change the viewing angle of the image and rectify. An application of this can be mosaicing image as well, which creates a kind of panoramic image.


Part.1 Shoot the pictures

sticker
book


  The images above are going to be used as an example to simply show the change of viewing angle.







  The images above are going to be used as an example to show the change of viewing angle. And then, the images would be used to be stitched to create a panoramic image with mosaicing.

Part. 2 Recover Homographies

  Homography refers to the matrix that allows the projective transformation from one image to the other image. And for use, this is used to change the viewing angle. Solving the following matrix for h vector will give us the necessary points for homographies.



Part. 3 Warp the Images

  As we obtained the homographies, now we can apply inverse warping to get the image of changed viewing angle. And the following images are some of those examples. I tried to show how the object in front would look like if we changed the viewing angle as we are looking from top to bottom.

sticker
rectified

book
rectified




Part. 4 Blend Images into a Mosaic

  Using the same idea from part 3, I can rectify images and stitch them together to create a panoramic image. We first pad the images so we do not lose information. Then, obtain the common points between the images in order to stitch them in a correct way.


left
middle
right

rectified
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rectified
middle
rectified
right
blended

left
middle
right

rectified
left
rectified
middle
rectified
right

blended


left
middle
right

rectified
left
rectified
middle
rectified
right

blended