Paper currency detecting method and device

The invention discloses a paper currency detecting method. A paper currency recognition device is internally provided with an image acquisition unit, a light source and a currency delivering channel, wherein the image acquisition unit and the light source are respectively located on two sides of the currency delivering channel of the paper currency recognition device. The paper currency detecting method comprises the following steps: in a process for delivering a paper currency to be detected through the currency delivering channel, acquiring and processing the full-breadth image of the paper currency by the image acquisition unit through transmission light of the light source, transmitting through the paper currency; extracting anti-counterfeiting feature information from the processed full-breadth image; and judging the authenticity of the paper currency according to the processed image and/or the anti-counterfeiting feature information. The invention further provides a corresponding device. A paper currency detection scheme provided by the invention is beneficial to overcoming of the limitedness of processing with a reflection-type imaging algorithm, and is easy to realize with lower cost and fast and accurate detection, thus, false money can be accurately detected, and particularly, a more obvious effect on the false authentication can be achieved on a changed paper currency; and the paper currency detecting method and device can be used for accurately detecting complementary opposite printing type features of offset printing.