An image metrology method using linear array CCD camera is discussed in this paper. With the digital display working table that can move in Z、Y dimensions and rotate around the Z-axis

the 3-D external profile of an irregular rotary object is detected. In order to get the sub-pixel resolution

the original data image from CCD is processed by Marr's edge position detecting algorithm

and the zero-cross position is detected by the least square fitting method. In the measurement of an irregular rotary part which has the size of Φ200 mm

the measure resolution of the detecting system reaches the μm level.