MXPA98010172A - Validator of bancar documents - Google Patents

Abstract

A bank document detector has four LEDs that detect the red, green, blue and infrared reflection and transmissibility of the bank document. The signals of the amplifiers are fed to a microcomputer and / or microprocessor for analysis

Description

VALIDATOR OF BANK DOCUMENTS Description Background of the Invention The present invention relates generally to a bank document validator and more specifically to a bank document validator designed to distinguish between authentic documents and false documents. Validation of money in circulation is used very popularly in relation to a service product. With the growing demand of entrepreneurs for increased sales or increased financial transactions, innovative methods are required to maintain growth. Those who accept bank documents have responded to the merchants' call by providing the ability to mechanically facilitate high-cost transactions. The validators of bank documents are very popular in the automatic distributors of beverages, food, products, and in the gambling and betting businesses. The -changing machines, that is, put coins into circulation to facilitate drinks, telephone service and many other transactions are popular. In addition, validators of bank or money documents are also used to authenticate other financial instruments such as stocks, securities and securities. Therefore, as used herein, the term "bank documents" or "banknotes" will include all such applications. The majority of bank documents, or banknotes, are badly damaged or mutilated before being removed from circulation. Before they are removed from circulation, the tickets are for legal use and are expected to be used in transactions. Validators of known bank documents have difficulty validating used and mutilated banknotes. The acceptance of such authentic notes is always less than 1% in a money validator in circulation. The elimination of false documents is a very demanding requirement. Put simply, all non-authentic notes presented to the validator of bank documents should be rejected automatically, regardless of origin. It is even expected that documents that are not yet in circulation will be detected and rejected when they appear. The. Most bank document validators have been designed for generalized market objectives, and the industry has allowed reduced performance in one or more detection areas, in favor of the one-size-fits-all approach. Unfortunately, most applications for the end user are very different and the size for all is not suitable for everyone. In fact, the losses of the automatic beverage dispensers or the losses of the product of the music machines are not even comparable with those of the machines of change, the postal systems or the applications of ATM (machine of automatic window). Even frequently the criteria for use is the cost of the system. The manufacturers of bank document validators compete in applications where their machines comply with what is most suitable for the client. Frequently, machines are allowed to enter if they do not comply with the market where there are no good faith means for quality of execution tests, and quality machine manufacturers are often forced to provide additional services or make reductions. price to maintain sales. By far, the validation of bank documents has been very popular in the United States, with the introduction of the validator of -the automatic beverage dispensers. These validation systems were simple, but efficient. The biggest failure related to the technology implemented in the validation process. Each and every one of the manufacturers were victims of casual fake. As validators of bank documents proliferated for many types of applications, demands for better systems grew more and more. The original systems depended on the magnetic information inherent in the authentic currency of the United States and some foreign countries. However, this technique is very susceptible to modern copying machines. Most offices and libraries in the United States have copying machines in black and white, and almost everyone has access to one. The optical systems began to make employees with the intention of improving safety. These systems usually work with some kind of image analysis technique. They are susceptible to poor performance with used and mutilated bills as well as very new documents. The validators of bank documents mostly use both optical and magnetic systems in an effort to gain maximum validation performance and security. In systems where magnetism is used, it is not uncommon for bills designed with the narrowest pitch possible that will cancel the system. In optical systems, the image of a ticket is reproduced easily with modern photocopying techniques. Often the image is improved e? specific areas to specifically cheat the validator of bank documents. Bank documents around the world share at least one thing in common: none of them is immune to counterfeiting. Casual facsimile counterfeiting is increasing with the increase in the possibility of having access to technology. Also the demand for systems for money in circulation is increasing.

By far the biggest advance in bank document validators is in the implementation of optical systems. Optical devices have been used in a transmissive and reflective manner. Optical systems are very good at analyzing money in circulation, since all the bills are designed to be recognized by the naked eye. Many features such as watermarks, security strips and color strips inserted as deterrents against counterfeiting can be detected primarily with the naked eye. Therefore, it is reasonable to understand why people have high hopes for electronic vision systems. Unfortunately, the human model for the detection of counterfeiting can not be developed electronically in the validation systems of bank documents because the cost would be prohibitive. A common method used is to measure the reflected signal responses, or transmitted through the printed or unprinted areas on the surface of a bank document, using common light supplies and comparing the result with an image stored in the memory of the bank. validator of money in circulation. The greatest difficulties are the adequate detection in the very new bank documents, and the degraded image that is the result of the used bank documents, whose difficulties are included in the false registries of impression and the rejection of the acceptance of falsifications. In the execution of the spectral analysis it is possible to characterize the reflective, transmissive and abscessive properties inherent in authentic banking documents. With light of wavelengths focused narrowly between ultraviolet and infrared rays, it is possible to determine the chemical composition of bank documents, as used in the scientific analysis of other chemical studies, and it is possible to store the results on a base of data for later comparison. In fact, the use of the strictly controlled "chemical signature" of bank documents would be adequate to detect fraud and forgery. However, implementing a spectrum analyzer in the bank document validation system would be prohibitive both in terms of cost and time required to perform a scan of the entire light spectrum for each point along the length of a bank document. . The focus of the spectral analysis is not necessarily a system of the type of fine resolution that depends on the printed image of the bank documents. It is a system that depends on the "signature bands" of authentic banking documents as they are generated by the absorbance, reflectance and transmission of specific wavelengths of light. An individual detector with various modified light emitting diodes (LEDs) is used (filtered) in such a way that only a specific wavelength of light (+) a tolerance (say 5 manometer) is emitted by each LED. The common detector measures the effect of reflectance or absorbance, transmission of bank documents to each LED individually and in combination. Thus a signature of the bank document is created as it responds to various narrow wavelengths of light by reacting on an individual area of the bill as measured by and individual detector, the system as described would provide the greatest benefit if it were employed as an arrangement of said subsystems, 'facilitating maximum security and resistance to the formation of strips of authentic bank documents. Validation techniques have been thwarted by the ability of individuals to replicate the inherent characteristics of bank documents with engineering facsimiles. Casual fake has at its disposal a variety of tools that are sufficient to generate reasonable facsimiles to thwart even the best money validator in circulation. Copying machines, in black and white, color copiers, fax machines, inkjet copiers, computers- and scanners are tools that can be used to thwart the common validator of bank documents. Some of these methods are very detailed and complex, however, none uses the exact chemistry found when recording the inks and dyes used in the printing of bank documents. Current bank document validator technology typically uses one or more optical sensors to detect optical reflection and / or absorption characteristics of bank documents. Many systems incorporate emitters and detectors that operate at two or more wavelengths. These units usually take various points in discrete paths or channels along the length axis of a bank document. By comparing the results shown with the previously stored results of the actual bank documents, a determination can be made regarding the type and authenticity of the bank document. Typically, the emitter / detector pairs comprise at least one set of units sensitive to infrared light. This allows data to be taken for almost all currencies, regardless of the visible color of the bank document. However, a disadvantage in this method is that a two-tone copy (black and white) or a copy made on colored paper can be devised which will produce data that mimic a real bank document, making a false bank document accepted as if it were authentic. As color copy technology has improved, it has also become possible to produce almost identical color copies in the visual spectrum to real bank documents. Many countries constantly change their money in circulation to limit the falsification of bank documents, reduce production costs, improve longevity, etc. Several countries also use bank documents of different widths. These different widths are difficult to accommodate in an individual validation unit since the data channel for the narrower bank documents will vary depending on the insertion location in the unit. This usually requires several databases that are developed for a denomination. During the validation process it is necessary to scrutinize each of these databases in succession, and then decide if a comparison is possible. This can result in a process that requires several seconds, which can be worrying or annoying for the user. Because most currencies in the world use different color combinations according to different denominations, a validator that can detect these colors would be able to select which database to use to make the comparisons with the bank document. This would reduce the processing time in a significant way since only one search of a set of databases is required. The two-tone copies can be eliminated since there would be no color in the collected data. The printed copies on colored paper could also be eliminated since the useful variations in the color on the real currency would be lost. By comparing the color data with the infrared data, the acceptance of color copies could be greatly reduced. Typical systems for detecting color use three detectors for the red, green and blue portions of the visible spectrum, and white light to illuminate the object. White light supplies that produce a uniform spectrum of light are usually expensive, bulky or require a complicated power supply. Each detector has a filter to allow only a specific pressure of the spectrum to pass. By combining the information "from the three detectors and by applying mathematical equations to the data, the color of an object can be determined." What all current bank document validators lack, and that it is desirable to have, is the ability to accurately and quickly determine the authenticity of the bank document while keeping the cost and size of the validator to a minimum. This need that has existed for a long time, but has so far not been satisfied with respect to a compact and relatively cheap bank document validator that can distinguish accurately and quickly between authentic and false bank documents can now be satisfied by means of the invention described hereinafter. Brief description of the invention In accordance with the present invention a bank document validator is composed of a detector to detect light from the LEDs reflected to the surface and transmitted through a selected bank document to determine the authenticity thereof. The system comprises four transmitters, a detector and a programmable gain amplifier. The full details of the present invention are set forth in the following description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the nature and objects of the invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings, which: Figure 1 schematically shows the present invention; Figure 2 shows schematically the function of the detection units. Similar reference numbers refer to similar parts throughout the different views of the drawings. Description of the Preferred Modes The objective of this invention is a method to determine the color of a bank document, in a simple, accurate and cheap way. This method uses a diode detector PIN whose spectral characteristics are similar to those of the human eye. • While the typical bill validator needs to be small and cheap, the preferred method of construction is not one that contains multiple detectors and white light supplies. The present embodiment of the invention uses different LEDs of visible color to illuminate the bill and an IR detector with sensitivity in the visible spectrum. Four LED's are contained in the system, namely red, green, blue and infrared, arranged in such a way as to shine on the same fixed point. The detector is mounted to collect reflected or transmitted light from the LEDs. In. In the present invention, the photodiode 10 consisting of multiple LEDs is arranged to selectively detect the light emission from the bank document being tested, as it passes through the validation section of the validator. the bank documents. The signal, that is, the current produced by the photodiode 10 from a selected LED is fed to an amplifier section generally illustrated by the number 12, whose operation, which includes the sequence order of the output from this section 12, is controlled by a computer control stage (CPU) 14 for analysis, display, and determination of the validity of the bank document. Depending on the results obtained, the bank documents are accepted or rejected. Specifically, as seen in Figure 2, the current from the photodiode, obtained through the LED 18, is fed to a first stage amplifier 20 where it is converted to a voltage. The input signal current is filtered by a capacitor 22 in the first stage to reduce the noise coming from the external sources. The amplifier 20 is a low compensation voltage of the type to reduce any error caused by the high gain of the circuit. The output from the first stage is input to the feedback point of a 24 D / A multiplier converter. The D / A in conjunction with a second amplifier 26 comprises a programmable gain stage, i.e., an amplifier whose gain can be modified by a microprocessor 28. The output at the terminal 30 of the second amplifier 26 can thus be balanced with respect to the light or the wavelength of a selected color, since each wavelength of light can be defined by a different gain positioning, to balance the final output. A final amplifier stage 32 acts as an inverter and low pass filter (interruption between IKhz and up) to reduce the noise coming from external sources and to avoid the broad equivalent labeling of the signal in the A / D converter. The output from the third amplifier 32 or final amplifier is passed through the terminal 34 to the control CPU 16. To take a sample, the LED 18 is illuminated, the gain of the amplifier 20 is set, and a sample is taken at the output of the filter stage by a 24 A / D converter. The output from the A / D converter is fed to the programmable gain control amplifier 26 and the processor 28, which is then passed in sequence through red, green, blue and infrared. The output is then stored in the memory of the CPU for processing, displaying and controlling the validating apparatus. The arrangement shown in Figure 1 uses four separate amplifier channels R, G, B for each LED of red, green and blue respectively and IR for infrared light. These are non-programmable frequency amplifiers prefixed for each color respectively. Filter and associated gain circuits are also required, although, their operation essentially as described with respect to Figure 2 provide separate amplifier channels for each LED color. Although it comprises more parts, the gain of each stage can be set individually at the factory. This eliminates the need for adjustment in the field by one skilled in the art. Occasionally the unit may require service as to old parts, although this is not a major problem. Therefore the arrangement shown in Figure 2, wherein the color output is controlled and balanced by the microprocessor 28 through an individual gain / amplifier circuit is preferred. This arrangement eliminates the separate amplifier for each color by reducing the number of parts required and improves the linearity of the system. As mentioned in the above, the present invention allows the use of either reflected or transmitted light to be detected. One reason to use the transmitted light is to help compensate for the brightness change of the LEDs due to temperature changes. Validators are used in different environmental media from the Sahara Desert to Greenland for automatic vending applications. The extreme temperatures of -25 ° C to + 50 ° C are not unknown. Each light output of the LED's for a given current is proportional to the temperature so that the temperature increases, the light output decreases and vice versa. In addition, LEDs made in different processes respond differently to temperature in varying degrees. Suffice it to say that the red, green and blue devices behave very differently with each other with the variation of temperature. While the present invention requires that the response to white light remain sufficiently constant, a machine adjusted to operate in the month of September in New York will not work in the Sahara or in Greenland. To compensate for temperature variation, the programmable gain stage is provided with a video adjustment detector to monitor and constantly brightness the LED and adjust the gain for each light color channel. When a video adjustment is made the relative readings for the transmitted light are made for each such channel, without a bank document or note between the LEDs and the detector. These readings are stored in memory. As the validator waits for a bill to be inserted, the microprocessor monitors the LEDs and modifies the gains to keep them identical with the stored readings. This maintains the balance on the expected temperature variations. A special card is inserted to adjust the unit. This card has on it the same regions of white, black, red, green and blue. As each different area passes below the detector, the relative resistances of the responses are measured. An algorithm in the microprocessor then adjusts the D / A positions for each LED to achieve the proper balance. It will be noted that the entirety of the foregoing description and the accompanying drawings of the invention are to be considered in illustrative form and should not be considered in the limiting sense.

It will also be understood that the following claims are intended to cover -all of the modalities and generic and specific aspects of the invention described herein.

Claims (4)

1. In a validator of bank documents that have means to determine the validity of the bank document and to accept and reject the bank document, a system to determine the correct color of such bank document comprising, a light detector to detect the admission of light red, green, blue and infrared respectively from such bank document, A / D means to convert the output of the light detector to a digital signal, means to selectively limit the output gain of such A / D means to obtain a output signal indicative of that selected of such color, and means for providing such an output signal to the means for determining the validity of the bank document.

2. The system according to claim 1, characterized in that it includes means interposed between said light detector and such A / D converter means to amplify and filter the analogous signal.

3. The system according to claim 1 characterized in that said limiting means comprise an amplifier and a microprocessor unit for programmably controlling the gain of the amplifier to provide selected frequency levels of output.

4. The system according to claim 1 characterized in that said light stopping means comprise an arrangement of light detection photodiodes each prefixed for one of said respective colors.