Circle parameters calibration and data analysis of two-dimensional shape photomask

Two-dimensional shape photomask is widely used to calibrate and correct optical precision measurement system like image measurement instrument and to calibrate or distortion correction of camera probe with CCD/CMOS sensor. Among all 2-D shapes, circle is adopted frequently because of its information such as size, form and position. Standard photomask with circle shape is multi-parameter calibrated by high precision laser two-coordinate standard device based on coordinate measurement method. Roundness error is assessed by least square circle method. How center coordinate, radius and roundness of a circle affected by number of measurement points, incident light intensity and optical magnification of micro probe are analyzed. Test results indicate than that standard with circle shape could be calibrated with high precision.