Using Slanted Edge Analysis for Color Registration Measurement

Abstract

Abstract identify a region of interest (ROI)fit a linear equation to the centroid locationusing linear fit to line, project the image data along the edge direction to top or bottom edge of ROIapply window and compute edgederivativeyof this arraycompute the centroid of each line (LSF) A compute discrete Fourier transform (DFT) of this array‘bin’ data, sampled at 1/4 of original image samplingnormalize modulus as SFRcompute derivative in the x (pixel) direction using FIR filterreport resultstransform image data using the OECFOECFderive luminance record if data is R, G, B .store equationfor eachcolor recordcompute edge derivative of thisarray, and appl window to resultcompute discrete Fourier We describe a digital image processing method to measure translation error between color records, that can be computed from the acquired image. Several steps in the ISO 12233 standard for measurement of resolution for digital cameras are used to locate an edge for each color plane. The method has proven reliable and can be applied to images acquired from both digital cameras and scanners.