I took a couple pictures on my iphone of rectangular objects in a way that captured the perspective of their parallel lines. I then found the homographies of these images that projects them to remove perspective. Using the homographies, I rectified the images to remove their skewed perpsectives.
I took two pictures that I attempted to stitch together into mosaics. I left one image untouched while I found the homography of the other image to warp it into alignment with the first image. Then, I used linear blending to overlap the two images. I first horizontally aligned a coordinate of the right image to the corresponding coordinate on the left image. Then I selected more corresponding points between the left image and the shifted right image to construct the homography. After warping the left image by this homography, I then aligned the warped left image to the original right image.
