Given:
- two images of the same subject matter;
- the images have the same resolution, colour depth, and file format;
- the images differ in size and rotation; and
- two lists of (x, y) co-ordinates that correlate the images.
I would like to know:
- How do you transform the larger image so that it visually aligns to the second image?
- (Optional.) What are the minimum number of points needed to get an accurate transformation?
- (Optional.) How far apart do the points need to be to get an accurate transformation?
The transformation would need to rotate, scale, and possibly shear the larger image. Essentially, I want to create (or find) a program that does the following:
- Input two images (e.g., TIFFs).
- Click several anchor points on the small image.
- Click the several corresponding anchor points on the large image.
- Transform the large image such that it maps to the small image by aligning the anchor points.
This would help align pictures of the same stellar object. (For example, a hand-drawn picture from 1855 mapped to a photograph taken by Hubble in 2000.)
Many thanks in advance for any algorithms (preferably Java or similar pseudo-code), ideas or links to related open-source software packages.
This is called Image Registration.
Mathworks discusses this, Matlab has this ability, and more information is in the Elastix Manual.
Consider: