Discrimination is based on the detection of the inherent characteristics of the RMB to distinguish between true and false. The counting machine is an integrated product of mechatronics, which involves the knowledge of mechanical, electrical, optical and magnetic fields, and needs to cooperate with each other.

Fluorescence detection

The working principle of fluorescence detection is to detect the paper of RMB. Yuan manufactured special paper (including more than 85% of the high quality cotton), counterfeit money usually adopt after bleaching treatment of plain paper manufacturing, after bleaching treatment of paper in the ultraviolet (wavelength of 365 nm blue) will appear under the irradiation of fluorescence reaction (under the excitation of ultraviolet ray diffraction out of the blue light wavelength is 420-460 nm), the yuan is no fluorescence reaction. Therefore, using ultraviolet light source to illuminate the movement banknote and simultaneously use the silicon photocell to detect the fluorescence of the bill, can distinguish the real money. In order to eliminate the interference of environmental light on discrimination, it is necessary to install a filter that is consistent with the wavelength and the wavelength of the counterfeit money in the surface of the silicon photocell.

A. In fluorescence detection, two problems need to be paid attention to: 1. Test space for shading. The outside light enters the detection space can cause false report; 2. Uv light source and photocell dust proof. There is a large amount of dust in the counting process, and these dust adhesion to the surface of the light source will weaken the detection signal and cause the omissions.

B, to the fifth edition of the yuan, can simultaneously detect the fluorescent character (colorless fluorescent ink printing, use another silicon photocell detection, color filters through the wavelength and fluorescence wavelength response real bill) to improve the effect of scrutiny.

Magnetic detection

The working principle of magnetic detection is the use of large amount of real money (20, 50, 100 yuan) parts is using magnetic ink printing, through a set of detecting a magnetic head for sports money, through the analysis of magnetic circuit, can distinguish money of true and false.

In magnetic testing, the magnetic head is required to rub well with the bill. The high head is too high and the signal is large, causing false alarm. The head too low, the signal is weak, resulting in omission. The testing needs can be met by controlling the height of the head (by machining and assembly) and by loading the rubber wheel over the head of the head.

The magnetic detection method of RMB can be divided into four types:

(1) the detection of magnetism. In the market, the counting machine adopts this method, because it is easy to make, so the rate of counterfeiting is low.

(2) according to magnetic distribution, the detection of magnetism. Two or three groups of magnetic heads are used to detect the magnetism, and the discrimination level can be improved a notch, and the market part of the counting machine adopts this method.

(3) test the fifth version of RMB metal wire magnetism. At the present level, there is no magnetism in the test. According to our observation in the oscilloscope, the magnetism in the wire is very regular rectangular wave, and the quantity is also very accurate, because it is difficult to copy, in magnetic detection, such as to use this feature, will greatly improve the level of scrutiny.

(4) check the magnetic number of the fifth version of RMB. At the present level, there is no magnetism in the test. Because the horizontal number is a set of Numbers with certain magnetic properties, such as the magnetic quantity and size of the horizontal number, the discrimination level can be greatly improved.

Infrared penetration detection

The working principle of infrared penetration is the use of the yuan's paper is strong, high density and with gravure technology of printing ink thickness is higher, so the strong ability of the absorption of the infrared signal to identify money of true and false. The paper features with counterfeit money paper has certain differences, using infrared signals to penetrate testing on money, their ability to absorb infrared signal will be different, use of this principle, can realize jigan. It is important to note that the color and thickness of the ink also cause the difference in the infrared penetration capability. Therefore, it is necessary to perform mathematical operation and comparative analysis on the signal of infrared penetration detection.

Laser detection

Using a certain wavelength of infrared laser to illuminate the fluorescence of the fifth edition of the Chinese currency, the fluorescence word will produce a certain wavelength of laser, and the detection of the laser can be used to detect the authenticity of the money. Due to the difficulty of copying, it is accurate to discriminate.

Multispectral detection

Multi-spectral light source, lens array, image sensor unit array, control and signal amplification circuit and input and output interface are arranged into matrix with different wavelength of LED particles. Multispectral light source and lens array form optical path system, used for emitting light and reflected light focused on the renminbi to the image sensor cell array, using the multi-spectral image sensor image analysis function, identification was carried out on the money.

Quantitative qualitative analysis test.

Using high speed parallel AD conversion circuit, high fidelity acquisition signal, quantitative analysis of ultraviolet light can detect the counterfeit money with weak fluorescence reaction. Quantitative analysis of the magnetic ink of RMB; Fixed point analysis of infrared ink; The fuzzy mathematics theory is used to quantitatively quantify some factors which are not clear and easy to quantify, and a multi-level evaluation model of security performance evaluation is established.