Projective map — where it appears
An inverse perspective is a leaning plane
Ask a divergent construction what solid it depicts and it answers: a rectangle, four right angles, near edge equal to far. What the splay encodes is not the shape but the plane's tilt — and a real square on a plane leaning toward the camera really does photograph with its far edge wider.
A projection of a projection
Photograph a photograph and the composite map is a homography — four marks determine it and every other lands where they say, to 1e-13 px. Roll the print and the same four mispredict the rest by 30.5 px, which is why straightening a page of a thick book never quite works.
Named alongside it
The objects these essays reach for when they reach for this one.
Picture planeVanishing pointBack projectionCamera tiltCompositionCross ratioDemonstrationDepicted rectangleHomographyInverse perspectiveone-point perspectivereconstruction ambiguity