In the previous post, I described the Seasons project: a time-lapse of hundreds of pictures taken from nearly the same viewpoint over the years. The hardest challenge wasn't taking the pictures or assembling them, but aligning them.
You might have noticed the nearly part about viewpoint in the above paragraph. Indeed, it's an approximation. I'm a human being, not a tripod. The position changes ever so slightly, and so does the exact angle. My phone has changed over the years, from a Samsung S10 to an S21, and now I'm using an iPhone 14 Pro. Each of them has a different camera with a different focal length. The resulting photos look similar but are definitely not identical: slightly different scales and angles. Without any correction, the landscape appears to be moving a lot.
Alignment is the process of warping each photo so it looks like it was taken from exactly the same angle as a reference image.
OpenCV for feature matching
For image-related features, OpenCV is the go-to library.
