Please cite this article as: Liu MY, Cheung CF, Cheng CH, Su R, Leach R.K.A Gaussian process and image registration based stitching method for high dynamic range measurement of precision surfaces.Precision Engineering http://dx.doi.org/10. 1016/j.precisioneng.2017.04.017 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
A Gaussian
Highlights: It makes use of Gaussian process to model the sub-aperture measurement datasets to obtain the mean surface for registration, which is a novel method as comparing to traditional filtering methods, and provides better registration accuracy. Image registration and z shift method are used to simplify the 6 degrees of freedom 3D point cloud registration to a 3 degrees of freedom registration. Edge intensity data fusion method is used to fuse the overlapped region to provide a better transition between two datasets.
It provides a novel stitching solution for a wide range of optical measurement instruments for achieving high dynamic range optical measurement of precision surfaces Abstract: Optical instruments are widely used for precision surface measurement. However, the dynamic range of optical instruments, in terms of measurement area and resolution, is limited by the characteristics of the imaging and the detection systems. If a large area with a high resolution is required, multiple measurements need to be conducted and the resulting datasets needs to be stitched together. Traditional stitching methods use six degrees of freedom for the registration of the overlapped regions, which can result in high computational complexity. Moreover, measurement error increases with increasing measurement data. In this paper, a stitching method, based on a Gaussian process, image registration and edge intensity data fusion, is presented. Firstly, the stitched datasets are modelled by using a Gaussian process so as to determine the mean of each stitched tile. Secondly, the datasets are projected to a base plane. In this way, the three-dimensional datasets are transformed to two-dimensional (2D) images. The images are registered by using an (x, y) translation to simplify the complexity. By using a high precision linear stage that is integral to the measurement instrument, the rotational error becomes insignificant and the cumulative rotational error can be eliminated. The translational error can be compensated by the image registration process. The z direction registration is performed by a least-squares error algorithm and the (x, y, z) translational information is determined. Finally, the overlapped regions of the measurement datasets are fused together by the edge intensity ...