A number of binary image processing operations which were developed from a set theoretical approach that comes under the headings of Mathematical Morphology[?]. Some morphological operations are:
... April 16 - Fifi D'Orsay, actress (+ 1983)
April 22 - Robert Oppenheimer, physicist (+ 1967)
May 6 - Harry Martinson, swedish author, winner of the Nobel Prize in ...