This could be used like an optoacoustic version of the radio-frequency bar codes that are used by cars passing through the pay booths of automated toll roads or to tag some goods in shops.
这相当于一个光声版本的无线电频率条形码，可以用在需通过自动收费站的车上，或者给商品打价签。
2
In a way it is like a long-range version of the radio-frequency bar codes used by cars passing through the pay booths of automated toll roads or to tag some goods in shops.