Homography transformation

1. What is a homographic transformation?
2. Is homography a linear transformation?
3. Is homography an affine transformation?
4. Is homography a projective transformation?

What is a homographic transformation?

Homography, also referred to as planar homography, is a transformation that is occurring between two planes. In other words, it is a mapping between two planar projections of an image. It is represented by a 3x3 transformation matrix in a homogenous coordinates space.

Is homography a linear transformation?

Linear algebra holds many essential roles in computer graphics and computer vision. One of which is the transformation of 2D images through matrix multiplications. An example of such a transformation matrix is the Homography.

Is homography an affine transformation?

Homographies are transformations of a Euclidean space that preserve the alignment of points. Specific cases of homographies correspond to the conservation of more properties, such as parallelism (affine transformation), shape (similar transformation) or distances (Euclidean transformation).

Is homography a projective transformation?

Images of a planar scene composed into the same frame of reference by appropriate projective transformations. for a nonsingular 3×3 matrix H defined up to scale. This relationship is called a projective transformation (and is sometimes also known as a collineation or homography).