Abstract: A method and algorithm for measuring the symmetry (SYM=total symmetry) of N points based on counting the number of “elementary symmetric recognition acts”, or having two distances d(A,B) and d(C,D) be equal within a given tolerance t. The same algorithm can be adapted to measure un-normalized positional entropy deficit (UPED) and positional entropy of N points. These parameters (SYM and UPED) come out almost the same for small occupation numbers (1<=k<=4). Here the occupation number k is the number of equal distances in the figure for a given value d. The algorithm can be incorporated into an imaging device, such as computer graphic programs or cameras, to solve problems of defect detection, say in gems, or object detection.