title: Subaperture stitching tolerancing for annular ring geometry.
abstract: Subaperture stitching is an economical way to extend small-region, high-resolution interferometric metrology to cover large-aperture optics. Starting from system geometry and measurement noise knowledge, this work derives an analytical expression for how noise in an annular ring of subapertures leads to large-scale errors in the computed stitched surface. These errors scale as sin(πp/M)(-2) where p is the number of sine periods around the annular full-aperture and M is the number of subaperture measurements. Understanding how low-spatial-frequency surface errors arise from subaperture noise is necessary for tolerancing systems which use subaperture stitching.
authors.forename: Greg A
authors.initials: GA
authors.lastname: Smith
authors.forename: James H
authors.initials: JH
authors.lastname: Burge