plane-parallel plate — where it appears
Named by 2 essays across one field — each of them below, with the objects they name alongside it.
What survives a pane of glass
A slab of glass moves every point of a picture and moves no direction at all. So the camera recovered from a photograph taken through a display case is exactly the camera that took it — out of a picture in which nothing is where it was.
A wedge of glass turns the camera behind it
A pane with parallel faces moves every point and no direction, so the camera recovered through a window is the camera that took the picture. Tilt one face 2° and every direction turns, by 1.04° on the axis and 1.67° forty degrees off it. The best rotation of the frame, 1.14°, still leaves 0.94 px, and no homography does much better, so the picture is no longer a projection from the camera's centre. The camera recovered from three vanishing points through the same glass is turned 3.37° — three times as far — because vanishing points lie where the glass bends most.
Named alongside it
The objects these essays reach for when they reach for this one.
Camera calibrationFocal lengthRefractive indexVanishing pointHomographyLateral displacementModel errorPinholePrincipal pointSnell's law