Patent ID: 6731392
Filing Date: 2004-05-04
Classification: G01D

Abstract:
A method for measuring displacement of a moving object by using a line scan camera, comprising the steps of:fixedly attaching a displacement measurement marker to a surface of the moving object, the marker comprising a plurality of repeatedly arranged figures having the same size and shape, each of the figures being measurable by means of the line scan camera and asymmetric with respect to a direction of a scan line of the line scan camera; setting coordinate systems of the displacement measurement marker, and obtaining general functional formulas for two lines of an n-th (n= . . . , âˆ’3, âˆ’2, âˆ’1, 0, 1, 2, 3, . . . ) figure of the displacement measurement marker at time t=0; obtaining general equations for intersection points between the scan line and the n-th two lines; obtaining two general distance ratios of the intersection points for an arbitrary integer of n from the general equation for the two intersection points; obtaining a general functional formula for the scan line having a gradient a and a y-intercept b for expressing as a general equation for the arbitrary integer of n from the two distance ratios; continuously photographing the displacement measurement marker moving together with the object by the line scan camera; obtaining two actual distance ratios from images photographed by the line scan camera; substituting the two actual distance ratios obtained from the images into the general equation having the gradient a and the y-intercept b so as to obtain an actual functional formula for the scan line; obtaining a central coordinate PC of the scan line by means of the actual functional formula for the scan line; and obtaining a relative displacement and a rotational angle between central coordinates of the scan line obtained for arbitrary time between t=0 and t=t.