Separation of tilt errors from measured data of aspheric surface without datum

As improper installation for aspherical component will inevitably bring the tilt errors to the measured data, the reliability of measured data reduces. Considering that the characteristics of a general elliptic equation include information about direction and location, this paper presents a method based on ellipse fitting to remove tilt errors, which are included in the sampled data of meridian of aspherical component. The experimental results verify the reasonable and correctness of this method. Consequently, this method can effectively isolate the tilt errors from the measured data, simplify the detection method and improve the processing efficiency.