Homographic Calibration (Structure)

gtoledo3's picture

Awhile ago, I asked about warping vectors in a way similar to quad warping. Jersmi supplied a really great example of how to do this with js that he'd obtained from a colleague (I believe - I'm sure jersmi can clarify). It was geared towards transforming a single vector.

This is a tweak of the composition that allows one to transform many x/y coordinates at once, and output a structure that's suitable for gl tools type structure patches.

Because it makes use of a QC iterator and javascript, it won't be quite as quick as a gpu accelerated method, though it will be potentially more stable across various Apple computers, than an OpenCL type implementation.

Smallish (in the dozens->low hundreds) structure counts will likely reveal minimal measurable difference. That said, it would probably benefit performance wise from being implemented in a plugin, and using GFList to handle the structure. It should also probably be re-jiggered to take in a 2 lane vector structure instead of two one lane inputs. This is pretty handy as is though.

The composition will need Structure Tools because I made the single lane structures with the patch instead of using javascript. If you don't have it, either install it, or make two single lane structures of identical count with js and plug in.