Patent ID: 7819320

Claim:
A method for y-axis beam pointing-error correction in an optical reader-scanner having pointing-error, the method comprising: determining the y-pointing error for each beam arranged in a column along the y-axis; accomplishing N scans across a row of wells of a microplate with a beam along the x-axis, each scan having a separation from any adjacent scan along the y-axis of Δs, and each scanned row having the center of the N scans offset by the y-pointing error (PE actual ) of the beam for that row; and eliminating scan lines so that the center of remaining scan lines is ±Δs/4, where scan lines are eliminated by calculating the value of equation (1): round {PE actual /(Δs/2) } (1) where “round” rounds the result in the brackets to the nearest integer, the number of scan lines eliminated is the absolute value of equation (1): |round {PE actual /(Δs/2) }| according to: if round {PE actual /(Δs/2)} is zero, then no scan lines are eliminated; if round {PE actual /(Δs/2)} is positive, then the one or more scan lines to be eliminated has the largest y-coordinate(s); or if round {PE actual /(Δs/2)} is negative, then the one or more scan lines to be eliminated has the smallest y coordinate(s).