How to barcode scanners instantly detect what an item is, despite the barcode being at any angle and often on a crinkled surface, completeley changing the look of the code from the scanner’s perspective?

Question

How to barcode scanners instantly detect what an item is, despite the barcode being at any angle and often on a crinkled surface, completeley changing the look of the code from the scanner’s perspective?

In: Technology

Answer 1

A barcode is a 1 dimensional code.

The fact that it’s drawn in a 2 dimensional shape simply allows for it to be accurately read from a number of angles and positions. A little bit of crinkle or if the reader is a little diagonal doesn’t really affect how the reader sees the lines in the code. The biggest threat to reading a barcode is if it’s underneath a reflective cellophane, or partially covered by a price tag.

In truth, all those lines in a barcode really look something like this:

https://puu.sh/EJfL9/9824e1e6c6.png

Each bars width, and the empty space between corresponds to a number, with an identifiable “start” and “end” character which is always present for certain barcode types. Really a barcode is nothing more than a 1 pixel tall font.

If we printed barcodes, however, just 1 pixel high it would be excruciating for the cashier to line up the little laser gun directly over the line, so we stretch them tall that way if the line is at the top of the code, or the bottom, or even diagonally across it, the ratios between each bar are maintained, and it can be read. The absolute width of each line is irrelevant in order to read it, just the relative width compared to the adjacent bars (much like changing the size of a font doesn’t change the meaning of the words).

EDIT: Reddit didn’t like how I showed the barcode example before