Abstract:
An optical recognition device for recognizing a certain type of sheets, e.g. money, includes at least one light source, at least one diverge device, at least two optical sensors, and a recognition circuit. The diverge device changes the course of light emitted from the light source into two separate lights on the sheet to be recognized. The optical sensors separately collect two response images from the sheet and the recognition device recognizes the sheet with the two response images.

Description:
RELATED APPLICATIONS  
       [0001]     The present application is based on, and claims priority from, Taiwan Application Serial Number 93124228, filed Aug. 12, 2004, the disclosure of which is hereby incorporated by reference herein in its entirety.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of Invention  
         [0003]     The invention relates to an optical recognition device and the method thereof. In particular, the invention relates to an optical device and method for recognizing a certain type of sheets.  
         [0004]     2. Related Art  
         [0005]     Due to the advance of electronic techniques and the increase in human costs, more and more jobs are left to automated machines, such as various kinds of vending machines and exchange machines. At first, automated machines only accept small-value coins. They recognize the coins by their volumes, densities, and conductivities. However, as they accept higher-value currencies, it is inevitable for these machines to process such bills.  
         [0006]     However, identifying whether a bill is true or fake is much harder than identifying a coin. Therefore, many people have proposed methods to recognize bills and there values thereof. For example, one can add a line using special magnetic ink on a bill. Then it is possible to recognize the bill through magnetism detection.  
         [0007]     Of course, optical recognition is a most direct method. Yet it also faces the highest difficulty because most image recognition programs involve complicated algorithms. This increases the costs of the automated machines and makes them more difficult to become popular.  
         [0008]     In fact, aside from currency bills, identifications and various kinds of valued certificates also have similar problems to be solved. Therefore, it is of great value to provide a device that can effectively recognize a certain type of sheets at a lower cost and the method thereof.  
       SUMMARY OF THE INVENTION  
       [0009]     An objective of the invention is to provide an effect and low-cost optical recognition device and the method thereof.  
         [0010]     The invention discloses an optical recognition device for recognizing a certain type of sheets, e.g. money.  
         [0011]     The optical recognition device includes at least a light source, a diverge device, at least two optical sensors, and a recognition circuit. Each light source has a corresponding diverge device to separate the light emitted from the light source into two separate beams toward the sheet to be recognized. The optical sensors separately collect two response images from the sheet and send them to the recognition circuit for recognition.  
         [0012]     The diver device consists of one or more prisms. In order for the beam to project onto the sheet to be recognized and for the response images to clearly show on the optical sensors, one or more lenses may be installed on the courses of the beams for converging the beams.  
         [0013]     The light source, the diverge device, and the lenses can be made into a module to speed up the fabrication and lower the cost.  
         [0014]     Thus, the invention has at least the following advantages. First, the invention only needs on light source for the two optical sensors to sense two different regions. The device cost is lowered. Secondly, the light source, the diverge device, and the lenses can be made into a module. In addition, since there are not too many required devices, more optical sensors can be disposed into the limited space, increasing the scanning and sampling range of the sheet to be recognized. This is of great help in sheet recognition. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     These and other features, aspects and advantages of the invention will become apparent by reference to the following description and accompanying drawings which are given by way of illustration only, and thus are not limitative of the invention, and wherein:  
         [0016]      FIG. 1 ( a ) is a schematic view of an embodiment of the invention;  
         [0017]      FIG. 1 ( b ) is a schematic view of moving the sheet to be recognized;  
         [0018]      FIG. 2  is a schematic view of the preferred embodiment of the invention;  
         [0019]      FIG. 3  is an exploded view of the devices in the preferred embodiment of the invention;  
         [0020]      FIG. 4 ( a ) is a schematic view of some devices in the optical module;  
         [0021]      FIG. 4 ( b ) is a schematic view of some devices in the optical module;  
         [0022]      FIG. 4 ( c ) is a schematic view of some devices in the optical module;  
         [0023]      FIG. 5  shows the operation of some devices in the optical module;  
         [0024]      FIG. 6  shows the relation between another lens and the optical module; and  
         [0025]      FIG. 7  is a flowchart of an embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0026]     With reference to  FIG. 1 ( a ), the optical recognition device  10  is used to for recognizing a certain type of sheets  11 , such as paper bills, identifications, checks, or various kinds of value certificates. The optical recognition device  10  has a light source  102 , a diverge device  104  for the light source  102 , two optical sensors  106 , and a recognition circuit  108 .  
         [0027]     The light source  102  emits visible or invisible light  120 , which is split by the diverge device  104  into two separate beams  122 ,  124 . When a sheet of paper  11  passes through a detection area in a predetermined direction, the two beams shine on the detection area, generating two response images  126 ,  128 . The two optical sensors  106 , which may be CCD or CMOS image extraction circuits, receive respectively the response images  126 ,  128 , and transmit the received response images  126 ,  128  to the recognition circuit  108  for recognition.  
         [0028]      FIG. 1 ( b ) shows a sheet of paper  11  passes the detection area  13  in the predetermined direction  14 . Since the paper  11  continues its motion in the predetermined direction  14 , the data read by the optical sensors  16  are two tracks  112 ,  114  on the paper  11 . In other words, in this embodiment, we can read two testing tracks  112 ,  114  on the paper  11  using a single light source. The invention thus achieves the goal of building a simple structure with a low cost.  
         [0029]     In the following, we use a preferred embodiment to explain how the invention is implemented.  
         [0000]     Preferred Embodiment  
         [0030]      FIG. 2  gives an example of implementing the above-mentioned idea. The optical recognition device  20  can be installed in automated machines of various kinds purposes, e.g. vending machines, exchange machines, bill recognition machines. When the optical recognition device  20  is installed in an automated machine, a sheet of paper  21 , e.g. money, is dragged by a mechanical device, such as a stepping motor, inside the automated machine to repeatedly or non-repeatedly move through the detection area  231  of the optical recognition device  20 .  
         [0031]      FIG. 3  is an exploded view of the optical recognition device  20 . The optical recognition device  20  has an upper shell  201 , a circuit board  202 , an optical module  2031 , light sources  2041 ˜ 2043 , optical sensors  2051 ˜ 2054 , and a recognition circuit and a control circuit that are not shown in the drawing.  
         [0032]     The optical module  2031  has prisms  2061 ˜ 2063  corresponding to the light sources  2041 ˜ 2043 . Moreover, the optical module  2031  is also installed with lenses  2081 ˜ 2084  corresponding to the optical sensors  2051 ˜ 2054 . Using a support base, the optical module  2031  can be installed on the circuit board  202 .  
         [0033]     The optical module  2031  is comprised of several devices of the same structure. We explain the relations among them.  
         [0034]     With reference to FIGS.  4 ( a )-( c ), we see that the prism  2061  corresponds to the light source  2041 . The lenses  2081 ,  2082  correspond respectively to the optical sensors  2051 ,  2052 .  FIG. 4 ( a ) is a three-dimensional view of the lenses  2081 ,  2082  observed from a specific direction.  FIG. 4 ( b ) is a three-dimensional view of the lenses  2081 ,  2082  and the prism  2061  observed from a specific direction.  FIG. 4 ( c ) provides a side view. Therefore, we can see from the drawings the structures and relations among the lenses  2081 ,  2082 ,  2061 . The other lenses  2083 ,  2084  and the prisms  2062 ,  2063  in the optical module  2031  have the same structures as the above-mentioned lenses  2081 ˜ 2082  and the prism  2061 . One can understand the structure of the optical recognition device  20  by looking at  FIG. 3 . We do not repeat the description here. Moreover, the lenses mentioned herein are made of transparent plastic, formed in a single body.  
         [0035]      FIG. 5  shows how to use the lenses  2081 ,  2082  and the prism  2061  to corporate with the light source  2041  and the optical sensors  2051 ,  2052 .  
         [0036]     When in use, the light emitted by the light source  2041  is split by the prism  2061  into two separate beams toward the sheet of paper  21 . Corresponding to the beam projection, two response images are produced and converged by the lenses  2081 ,  2082  onto the optical sensors  2051 ,  2052 . The optical sensors  2051 ,  2052  are connected to a recognition circuit (not shown), which deciphers the information of the sheet  21  and determines whether it is true and its value.  
         [0037]      FIG. 6  shows a schematic view of adding an additional lens to the optical recognition device  20 . In order for the light emitted by the light sources  2041 ˜ 2043  to converge on the sheet  21  for a better image quality, one or more lenses can be added to converge the beams. In  FIG. 6 , for example, a lens  2311  is added above the optical module  2031 . The lens  2311  can be installed at the detection area  231  of the upper shell  201  with a surface facing the sheet  21 . This provides a better converging effect on the response images.  
         [0038]     Moreover, the lenses  2081 ˜ 2084  and the prisms  2061 ˜ 2063  are disposed in an interleaving way. In practice, each of the light sources  2041 ˜ 2043  is used simultaneously for two of the optical sensors  2051 ˜ 2054 . Aside from the boundary optical sensors  2051 ,  2054 , other optical sensors  2052 ,  2053  can receive the response images from the sheet  21  projected by two light sources. In this case, we use the control circuit (not shown) to control the light-emitting sequence of the light sources  2041 ˜ 2043 . The recognition circuit  271  also uses the light-emitting sequence for recognition. Through many different combinations, the invention obtains the reactions of the sheet to different light sources, rendering a more accurate recognition result.  
         [0039]     Since the sheet has different response images for different light sources, one can obtain more information about the sheet to be recognized  21  by adjusting and setting the light sources. For example, when recognizing a bill, such as a NT currency bill, experience tells us that the following light source configuration can render a fairly accurate test result. The light sources  2041 ,  2043  in  FIG. 3  should install light emitting diodes (LED) that emit orange light. The light source  2042  is installed with an invisible light LED. The light source  2044  is installed with a red LED. Moreover, the light source  2043  is further installed with an invisible light LED. The invisible light mentioned here refers to infrared (IR) or ultraviolet (UV) light.  
         [0040]     We use  FIG. 7  to explain the implementation of the invention. First, the sheet to be recognized passes a detection area in a predetermined direction (step  702 ). A light source generates light of at least one specific wavelength (step  704 ). A diverge device splits the light emitted by the light source into two separate beams projected toward the sheet to be recognized (step  706 ). The response images generated from the beams projected onto the sheet are collected for recognition (step  708 ).  
         [0041]     While the invention has been described by way of example and in terms of the preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements as would be apparent to those skilled in the art. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.