The invention of barcodes (条形码) comes from a very simple idea. We only need to give each product a specific(具体的) number and print it. We could simply print the number itself. But this can cause problems. For example, an unclearly printed" seven" could look like a" one" to a computer. And "nine "looks similar to "six "if you turn it upside down. We need a better way of printing numbers so that they can be read correctly at high speeds. That's the problem barcodes solve.
Each number in a barcode is shown by seven same stripes(条). For example, the number "one" is shown in turn by two white stripes, two black stripes, two white stripes, and one black stripe.
A barcode includes different parts and each one provides a specific meaning. For example, 690-692 is the barcode for China. The next part tells you who produced the product. The final part is about the product itself. This is how barcodes work.
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A. It's also true for "three" and "eight". B. The first part of a barcode tells you where the product was made. C. Even if you turn it upside down, it isn't similar to any other number. D. Then computers can read it directly. E. These stripes are either black or white to show the number 1 to 9. |
