Concave function pointwise minimum of two concave functions, i.e. the set of concave functions on a given domain form a semifield. 3. Near a local maximum in the interior of the domain of a function, the function must be concave; as a partial converse, if the derivative of a strictly concave function is zero at some point, then that point is a local maximum. 4. Any local maximum of a concave function is also a global maximum. A "strictly" concave function will have at most one global maximum. Concave function In mathematics, a concave function is the negative of a convex function.
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