Method Of Measuring Roundness Error Base On Electronic Speckle Pattern Interferometry

The roundness error refers to the changes of the revolving in the same section to its relatively ideal round in the volume. The roundness error of the surface contours of rotary mechanical parts has a direct impact on the functions of machines and equipment, now the main methods of roundness measurement are micrometer, roundness equipment, coordinate measuring machine and so on. But all the old methods are out-line, or the equipment is expensive, and some of them have the high environmental requirements.In order to solve the problem, the new method is researched based on electronic speckle pattern interferometry in this paper.First, the domestic developing and application of roundness error measurement and electronic speckle pattern interferometry technology is analysised, we think the method of roundness error measuring with electronic speckle pattern interferometry is feasible.Second, we analysis the measuring principle of electronic speckle pattern interferometry, introduce the size of speckle, electronic speckle pattern interferometry and the statistical properties of speckle. We study the measuring principle of electronic speckle pattern interferometry from the displacement measurement, phase-shift measurements, the surface-plane displacement measurement, displacement measurement and typical optical design to provide sufficient theory basis for the measuring system.Third, we study the image processing of the electronic speckle pattern interferometry in-depthly , analysis the way of the elimination of interference through a series of image processing such as pre-processing, binary and outline extraction, we get speckle interference fringes with smaller interference which lay a good foundation for the analysis of the interference fringes.Finally, the framework of the measurement system of roundness error is constructed, the major optical system is analysised. In the current experimental conditions, we do experiment research in roundness error measurement of the workpiec and the experimental results verify the feasibility. We aslo intrudce the way of improving the stability of the system and analysis the roundness error measuring result with the way of least squares.