Abstract:Aiming at roundness error evaluation with dense numerous sampling points, a new algorithm of roundness error evaluation based on Minimum Zone Circle (MZC) was presented. Two design key points and implementation steps of the algorithm were described in detail, and the computer program flow chart was given. This proposed algorithm mainly included the following two parts: with the centre of least square circle as original centre, a ninepoint method was firstly used to move the original centre toward the centre of minimum zone circle successively. Then threshold values were set, in the several peakpoint groups, the 4 points satisfying crossover principle were found, the roundness error based on MZC was acquired finally. Simulations in a great deal demonstrated that within a short time this algorithm calculated the accurate MZC roundness error based on thousands of sampling points. This algorithm can be used in CCD image measuring system, again revealed the roundness error can be evaluated efficiently and steadily, which further proved its practicability.