超市里条形码扫描的秘密

As the scan line hits the bar code, the black spaces absorb the light, while the white spaces reflect light. A photo diode in the scanner transforms the reflected light into an electrical signal, whick is amplified and translated into digital code by the scanner's microprocessor. This code is then fed into the POS system or store computer.我是jack，今年8岁，住在加拿大多伦多，grade 2（二年级）。5岁我从北京移居多伦多，进入本地学校从SK（类似幼儿园大班）开始接受纯粹的北美小学教育。如果你想学习英语，了解北美小学课堂内容，还有学校趣事，关注微信公众号“英语小小孩”！每天一条语音，不伤视力哦。