Multispectral image acquisition and processing method for contact image sensor

Abstract

The invention belongs to the field of financial tools and discloses a multispectral image acquisition and processing method for a contact image sensor, aiming at solving the defects in the prior art that noise points exist in an acquired image, overall brightness difference between segments of the acquired image is great, and images of the same paper money under different light sources cannot synchronously acquired. The method comprises the following steps: an upper multiple-light-source CIS image sensor and a lower multiple-light-source CIS image sensor which are symmetrical to each other are arranged to acquire original images; acquired analog signals are subjected to filtering and then are sent to two independent A / D sampling modules to be quantized so as to obtain digital signals; the A / D sampling modules send the digital signals to a FPGA (Field Programmable Gate Array) for compensating, splicing, compressing and storing; the FPGA sends the signals to a main control chip; the main control chip puts the two-path information into two independent address areas of an external RAM (Random Access Memory) for caching; after whole images are acquired, a DSP (Digital Signal Processor) takes out the images from the external RAM to process. The multispectral image acquisition and processing method has the advantages that the acquired images have less noise; the images of the paper money under different light sources can be synchronously acquired; the acquired images are relatively smooth and the quality of the images is relatively high.

Description

technical field [0001] The invention belongs to the field of financial equipment, in particular to a multi-spectral image acquisition and processing method of a contact image sensor. Background technique [0002] Contact image sensor, English name Contact Image Sensor, abbreviated as CIS. The contact image sensor closely arranges the photosensitive units and directly collects the light information reflected by the scanned manuscript. It has the advantages of low cost, no lens group, small size, and convenient installation. In the past, it was used in the fields of fax, scanning, banknote bill recognition, etc., and now it is also widely used in financial equipment banknote detectors, currency counting and detectors, ATM cash machines, and banknote sorting machines. The application of contact image sensors in financial equipment reduces the volume of banknote detectors, banknote detectors, ATM cash machines, and banknote sorting machines; increases the stability of image acq...

AI Technical Summary

Problems solved by technology

1. It is impossible to remove the interference of other signals in the circuit, so that there are noise points in the collected image; 2. It is impossible to overcome the difference in the brightness of the light source between each segment of the contact image sensor, so that the collected image segment and the segment The overall brightness varies greatly; 3. It is impossible to collect images under different light sources of the same banknote at the same time

Due to the existence of the above shortcomings, the accuracy of financial equipment banknote detectors, banknote detectors, ATM deposit and withdrawal machines, and banknote sorting machines is reduced, causing some counterfeit currency to flow into the market, banks and society, and bring serious harm to the country's finances.

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