DS5100 REFERENCE MANUAL9066 READING FEATURES6.1 ADVANCED CODE RECONSTRUCTION (ACR 4)The traditional way of barcode reading could be called “Linear Reading”. In this case, thelaser beam crosses the barcode symbol from its beginning to its end as shown in thefollowing figure:Laser BeamFigure 69 – Linear ReadingIn Advanced Code Reconstruction mode it is no longer necessary for the laser beam to crossthe label from the start to the end. With just a set of partial scans on the label (obtained usingthe motion of the label itself), the scanner is able to “reconstruct” the barcode. A typical set ofpartial scans is shown in the figure below:Code DirectionFigure 70 – Partial ScansNone of the partial scans contains the whole label. The decoder aligns each partial scancorrectly and combines them in order to obtain the entire code.The alignment is performed by calculating the time difference from one partial scan toanother using a reference code element.ACR4 therefore has an intrinsic ability to increase the reading percentage of damaged codesas in the examples below:ACR4™ ReadableFigure 71 – ACR4 Readable Codes
