Research On Displacement Measurement Of Micro/Nano-stage Based On Microscopic Vision

The progress and development of micro/nano technology has made a great driving effect on micro/nano manufacture,biotechnology,material science,electronic and in-formation science.And meanwhile,with the rapid development of this disciplines,novel micro/nano measurement technology is strongly demanded.As an important branch of micro/nano measurement technology,micro vision based method has been increasing attention for it's visible,non-contact,high precision and can be used in multiply-degree of freedom(multiply-DOF)system.In a micro-vision-measurement system,usually,we would pay our attention to the accuracy and efficiency performance which are decided by the hardware and the digital image processing algorithms.In order to measure the output of the micro/nano stage,we designed a micro-vision-measurement system based on optical microscope.In this proposed scheme,we would like to solve the problem of accuracy and efficiency in image processing algorithm;and the special research work is listed as follows:1)We designed a micro-vision-measurement system based on optical microscope,and then model this optical system as pinhole imaging.Based on this,we establish the Jacobin matrix between the image space and Cartesian space,and especially,we simplify the Jacobin matrix for 1-DOF nano/micro stage,and a angle measurement method based on "rigid body" is given for X-Y-? micro/nano stage.2)This paper proposed a fast block matching algorithm based on improved particle swarm optimizationn(PSO)for motion estimation,and this is a coarse to fine matching algorithm.In this algorithm,we consider block matching as a optimization problem and then we utilize PSO to get a coarse match result.In order to lower the computing consumption,we proposed a distance-based rules to update each particle's fitness,and then we can improve the efficiency.In addition,the iteration times is limited in a small range to avoid the low convergence rate in the latter iterations.In this way,we could get a coarse position and then we adopt full search algorithm(FS A)to search in a small region.Experiments verify the proposed algorithm is valid,and the the choosing of Ro(the threshold in distance-based rules)is discussed.3)The image sampled by the micro vision system is simple and we can binarize the image and extract the connected regions.After that,we could figure out the center of the connected region and get the displacement of the micro/micro stage.As far as the image sampled in X-Y-? micro/nano stage,we could extract edges and fill the closed contour to get the connected regions.In addition,experiments are done to verify our algorithm is valid.4)This paper analyze the accuracy and efficiency performance of those proposed algorithms.When the the micro/nano stage move to a subpix position,the maximum measurement error caused by the algorithms is analyzed.In the meanwhile,the effi-ciency of those proposed is analyzed and compared.In addition,the characteristic of each method is summarized.