Patent ID: 8333326

Claim:
A stacked barcode reader comprising: an image pickup section that captures an image of a stacked barcode in which character data is coded into barcode and displayed by bars and spaces; an image memory that stores the image data of said stacked barcode captured by said imaging pickup section; and a data processing section that has a decoding section for decoding the image data of said stacked barcode into character data; wherein said decoding section includes: a threshold calculating means that calculates a threshold value to measure line widths of the bars and the spaces of said stacked barcode by brightness values of multiple pixels that configure said image data; an n-th order differentiation calculating means that calculates an n-th order differentiation value, where n=1 or 2, by performing an n-th order differentiation on a scanned reflection coefficient waveform that shows the brightness values of the multiple pixels of the image data; a line width measuring means that measures the line widths of multiple bars and spaces of said stacked barcode based on said threshold or said n-th order differentiation value; a T-sequence measuring means that measures a T-sequence from the line widths of the bars and the spaces of said stacked barcode, measured by said line width measuring means; and a code word obtaining means that obtains a code word corresponding to the T-sequence measured by said T-sequence measuring means.