Calculation method of center and radius of minimum area circle

摘要

The present invention relates to a method for calculating the center and radius of a minimum area circle that can be applied to the minimum area method, which is one of the methods for measuring roundness. The average value of the X-axis and Y-axis data of the data is obtained and set as the current center, the radius interval (R1) of the inner and circumferential circle at the current center is obtained, and the distance from the current center to all the measured data is obtained. Set the point moved by a certain moving distance in the direction of the center opposite to the point closest to the direction to the next center, and find the radius interval R2 of the inner and outer circle at the next center, and find the inner and outer circle at the current center. If the radial distance of R1 is greater than the radial distance R2 of the inner and circumscribed circle at the next center, the next center is set as the current center and is expanded to the moving distance. Multiply by the ratio to set the moving distance, if the radius interval (R1) of the inner and circumscribed circle at the current center is less than the radius interval (R2) of the inner and circumscribed circle at the next center, the current center is maintained as it is and The process of setting the moving distance by multiplying the moving distance by the reduction ratio is such that the difference between the radial interval R2 of the inner and circumscribed circle at the current center and the radial interval R2 of the inner and circumscribed circle at the next center becomes very small or the moving distance Iterate until it becomes very small, characterized in that to calculate the radial interval of the inner and outer circle.