A recognition module comprises a detection unit for real-time detection and control of a banknote moving state, wherein at least one group of the through-beam sensors comprises a first sensor and two second sensors, the first sensor whereof is arranged on a midline of a banknote transmission channel, and the two second sensors are arranged at the upstream position of the banknote moving direction relative to the first sensor and are symmetrically distributed on the two sides of the midline of the banknote transmission channel. The condition for judging whether a start signal of an image data acquisition unit is effective is whether a banknote-triggered insertion event is detected by the first sensor; and the condition for judging whether an end signal of the acquisition unit is effective is whether a banknote-exit completion event is detected by three through-beam sensors.