Concave polygon does not contain all other vertices in its edges and interior. The convex hull of the concave polygon's vertices, and that of its edges, contains points that are exterior to the polygon. Concave polygon A simple polygon that is not convex is called concave, non-convex or reentrant. A concave polygon will always have at least one reflex interior angle—that is, an angle with a measure that is between 180 degrees and 360 degrees exclusive. Some lines containing interior points of a concave polygon intersect its boundary at more than two points. Some diagonals of a concave polygon lie partly or
Telecentric lens (or "collimated") illuminators, which produce a parallel light flow, often from LED sources. An image-space (or image-side) telecentric lens produces images of the same size regardless of the distance between the lens and the film or image sensor. This allows the lens to be focused to different distances without changing the size of the image. Image-space telecentric lenses have an exit pupil infinitely far in front of the lens; that is, if one looks in the back of the lens, the image of the aperture is very far away. At the film or image sensor, all of the chief rays