Implementation of algorithm to decode two-dimensional barcode PDF-417
Hee Il Hahn, Joung Koo Joung · 2003
We present a barcode reader to decode two-dimensional symbology PDF-417 and propose a novel method to extract the bar-space patterns directly from the gray-level barcode image, which employs the location and the distance between extreme points of each row of the barcode image. This algorithm proves to be very robust for high convolution distortion environments such as defocussing and warping, even under bad illumination conditions. If the scanned barcode image is a result of the convolution of a Gaussian-shaped point spread function with a bilevel image, popular image segmentation methods such as image thresholding cannot distinguish between very narrow bar-space patterns which are a couple of pixels wide. The proposed algorithm shows improved performance over current barcode readers.