Research of Zero Calibration in Conoscopic Holography Measurement Based on Image

Abstract

Non-contact measurement based on conoscopic holography is a kind of interferometry with common path, so it is not influenced much by other factors such as vibration. But the measurement result is affected by the uniformity of the crystal, which is analyzed in this paper, and corresponding method of adjustment based on image is discussed. And B-splines function is used to calculate zero position in measurement image, which is fitted over the patch image in the neighborhood of gray extreme points of the stripes, which is important to reduce the repeatability error, optimize design, and improve the accuracy of system.