Study On Topography Mosaic Algorithm In Measurement Of Multi-wavelength Surface Interferometry

With the rapidly development of Micro Electro Mechanical System(MEMS),the requirement of machining accuracy of micro structure is gradually improved,and the surface topography information of micro surface is often needed.Overall,MEMS has the characteristics of millimeter and micrometer in size,and it should meet the requirements of large size and high resolution at the same time when measuring micro surface topography.On the base of full investigation,combined the mosaic topography with multi phase-shifting microscopic interferometry measurement technology,the mosaic experiment system of multi phase-shifting microscopic interferometry can beestablished.By controlling the movement of the two-dimensional translation table,a good coincidence area between adjacent topography images can be achieved.Thus,a full size,spatial and high resolution whole 3D image is obtained.The main content of this paper is:(1)For obtaining 3D image data,We discussed the principle of phase shift interferometry,dual wavelength interferometry and multi wavelength interferometry measurement and analysed of their advantages and disadvantages.the wavelength switch and phase shift scanning interferometry was described in details.(2)On the basis of the existing interference measurement system,for large size and high resolution 3D surface topography,the control system of the two-dimensional translation table is introduced.we build a multi wavelength surface interferometry system,and analysis of the system structure.The two-dimensional translation table control system is introduced in this paper.It mainly includes two dimensional translation table,drive motor,motion control card and so on.(3)We study of the current on the three-dimensional topography mosaic method and analyzes the source of error in 3D interference measurement system to mosaic method for 3D images of the right.the traditional ICP algorithm is improved and we gives the 3D mosaic method and specific steps.(4)The volume experiment was carried out with the established multi wavelength surface topography interferometry measurement system.Using square wave,sine wave reticle templet for surface topography recovery experiments,and compared the Ra to Chinese Institute of Metrology.The relative errors are 4.09% and 4.17%.Therefore,The measurement system is feasibility in this paper.The influence of selecting the coincidence region on the image is also studied after mosaic.