ON THE REDUCTION OF SUB-PIXEL ERROR IN IMAGE BASED DISPLACEMENT MEASUREMENT

Alfredo Cigada, Remo Sala, Emanuele Zappa

Abstract

Image based measurement techniques allow for quick and contact-less measurement of single or multiple target displacement, shape, orientation and so on. The subpixel analysis increases the vision based displacement resolution. In the present paper resolution and uncertainty of 1D camera based displacement measurements is analysed, paying particular attention to the target geometry effect on the results. Comparison between camera based and laser interferometer displacement measurement is performed and some target modifications are tried, in order to reduce measurement uncertainty, due to sub-pixel systematic effect; the use of including the systematic effect into uncertainty, is wrong in theory but in practise often justified by the usual need of coarse and speed measurements.<BR /> The uncertainty in target displacement estimation given by three different image analysis algorithms is also tested in the case of rectangular, rhomboidal and circular targets.

Keywords

Sub-pixel, imaging, uncertainty

Download

PWC-2003-TC15-007.pdf

DOI

-

IMEKO TC

TC15 - Experimental Mechanics

Back to the proceedings