Find homography in D?

[Jordan Wilson]

On Sunday, 21 April 2024 at 14:57:33 UTC, Paolo Invernizzi wrote:
> Hi,
>
> Someone can point me to a D implementation of the classical 
> OpenCV find homography matrix?
>
> Thank you,
> Paolo

Something I wrote awhile ago...

```
import kaleidic.lubeck : svd;
import gfm.math;
import mir.ndslice : sliced;

auto generateTransformationArray(int[] p) {
     return generateTransformationArray(p[0],p[1],p[2],p[3]);
}

auto generateTransformationArray(int x, int y, int x_, int y_) {
     return [-x, -y, -1, 0, 0, 0, x*x_, y*x_, x_,
             0, 0, 0, -x, -y, -1, x*y_, y*y_, y_];
}

auto transformCoor (mat3d mat, vec3d vec) {
     auto res = mat * vec;
     return res / res[2];
}

auto findHomography (int[][] correspondances) {
     auto a = correspondances
                 .map!(a => a.generateTransformationArray)
                 .joiner
                 .array
                 .sliced(8,9);

     auto r = a.svd;
     auto homog = r.vt.back;
     return mat3d(homog.map!(a => a/homog.back).array);
}
```