1. A measurement system capable of figuring out a position of an edge of a pattern by finding a two-dimensional intensity distribution of a signal obtained from a patterned sample through observation by a microscope, wherein, when one of an edge of a pattern and the pattern in the two-dimensional intensity distribution is that of a line of the pattern or the line pattern itself, a first image processing is initially carried out to calculate an average of the two-dimensional signal intensity distribution for a given portion of the pattern, which given portion of the pattern includes both right and left edges of the line, by specifying a number of pixels, each with a two dimensional signal intensity, to be averaged in a direction perpendicular to the edges or line by specifying a first smoothing parameter Sm value, then another imaging processing is subsequentially carried out to calculate the edge position or the line width with respect to each of a plurality of subsequent smoothing parameter Sm values that are varied sequentially, thereby figuring out the dependency of each calculated edge position or line width on each one of the first and plurality of subsequent smoothing parameter Sm values.