Abstract:
An apparatus includes a pattern recognizer configured to identify a match of an image of a portion of a bill to one of a plurality of templates. The pattern recognizer is configured to use a rotation-invariant pattern matching algorithm. The apparatus further includes an output device to provide an indication when the match has been identified.

Description:
RELATED APPLICATIONS 
       [0001]    The present application is a continuation of and claims priority to U.S. patent application Ser. No. 10/776,930, filed Feb. 11, 2004, the contents of which are expressly incorporated by reference in their entirety. 
     
    
     FIELD OF THE DISCLOSURE 
       [0002]    The present disclosure relates to methods and systems for reading a denomination of currency. 
       DESCRIPTION OF THE RELATED ART 
       [0003]    People with low or no vision typically develop sophisticated methods to identify the denomination of currency in their possession. These methods typically involve folding and segmentation of bills in a unique manner for each denomination of currency. For example, $20 bills may be folded in a first unique way, and $10 bills may be folded in a second unique way. However, when receiving a bill such as when receiving change, the aforementioned people must trust that the individual giving them the bills are correctly identifying them. 
         [0004]    There is an existing device that reads bill denominations that uses standard bill reading technology, much like that found in a vending machine, and provides an audio output. The size of the device is significantly larger than the bill in order to scan the entire bill to read its denomination. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    The present invention is pointed out with particularity in the appended claims. However, other features are described in the following detailed description in conjunction with the accompanying drawings in which: 
           [0006]      FIG. 1  is a block diagram of an embodiment of the personal bill denomination reader; 
           [0007]      FIG. 2  shows an embodiment of the personal bill denomination reader integrated with a mobile telephone and its operation; and 
           [0008]      FIG. 3  shows an embodiment of the personal bill denomination reader having the form of a key fob. 
       
    
    
     DETAILED DESCRIPTION 
       [0009]    There is a need for a personal bill denomination reader that is readily available for a user, and allows him/her to use the reader in a discrete and secure way while providing the freedom to use paper money during everyday activities. 
         [0010]    To address this need and other needs, embodiments of a personal bill denomination reader with tactile output are disclosed herein. A specific tactile output pattern is generated for each recognized denomination of currency. The tactile output provides a high measure of security and privacy while the user “counts” his/her money, functions well in a noisy environment such as a restaurant, and is suitable for users who suffer a hearing impairment. The personal bill denomination reader can be integrated with a mobile telephone or a key fob to facilitate portability with the user. 
         [0011]      FIG. 1  is a block diagram of an embodiment of the personal bill denomination reader  10 . The personal bill denomination reader  10  comprises a digital camera  12  to capture an image of a bill  14 . The digital camera  12  can capture and store the image in response to a user-initiated depression of a button  16  or another user-initiated action. Optionally, the reader  10  includes a light source  20  to illuminate the bill  14  to support capturing images in dimly-lit places. The light source  20  may be activated in response to the user-initiated depression of the button  16  or another user-initiated action. 
         [0012]    The image of the bill  14  is taken from the perspective of one of the corners of the bill  14 . In practice, the user may identify a corner of the bill  14  by touch, then hold the reader  10  so that the digital camera  12  is proximate the corner, and press the button  16  to capture an image from the perspective of the corner and activate a bill identification feature. 
         [0013]    The captured image is processed by a pattern recognizer  22 . The pattern recognizer  22  compares the captured image to built-in images  24  of all standard bill denominations to match the captured image to one of the built-in images  24 . In the United States, the standard bill denominations may comprise $1, $2, $5, $10, $20, $50 and $100 bills, for example. Local bill denominations for other countries may be used in international embodiments. 
         [0014]    Since each bill has four corners and two sides, the built-in images  24  comprise at least eight built-in images per bill denomination, the built-in images comprising a corresponding image of each of four corners for each of two sides of the bill denomination. The built-in images  24  may also comprise built-in images for previous versions of the currency. For example, since modifications were made to the $20 bill in the year 2003, the built-in images  24  may comprise at least eight images of pre-2003 $20 bills, and at least eight more images of $20 bills issued in 2003. 
         [0015]    It is noted that the built-in images  24  may be represented within the personal bill denomination reader  10  either by actual images of bills or a transformation of the actual images of bills. 
         [0016]    The pattern recognizer  22  uses a rotation-invariant pattern matching algorithm so that the bill  14  can be recognized for various orientations of the bill  14  with respect to the reader  10 . Built into the algorithm is pattern matching for markings on the front and back of all standard bill denominations, which include current and previous versions of the currency. Since the number of templates is reasonably low, the pattern recognizer  22  can identify the bill  14  nearly instantaneously. 
         [0017]    Once a positive identification of the bill  14  has been made by the pattern recognizer  22 , the reader  10  reports the denomination of the bill  14  in a mode determined by an output selector  26 . The mode is selected from a tactile output mode, an audible tone mode and a speech mode. Preferably, the user can select the specific mode via a user input received by the reader  10 . 
         [0018]    In the tactile output mode, a tactile output device  30  generates a tactile output unique to the denomination of the bill  14  based on the match from the pattern recognizer  22 . The tactile output mode provides a high level of security in that other people near the user are not made aware of the denomination of the bill  14 . 
         [0019]    In one embodiment, the tactile output device  30  is capable of vibrating in a unique pattern of time and/or frequency for each denomination. Thus, the tactile output device  30  vibrates in a pattern unique to the denomination of the bill  14  based on the match from the pattern recognizer  22 . The user feels the vibration pattern and determines the denomination of the bill  14  based thereon. 
         [0020]    In another embodiment, the tactile output device  30  comprises a small dynamic Braille display to generate a Braille representation of the denomination of the bill  14  based on the match from the pattern recognizer  22 . The user touches the Braille display with his/her hand to sense the Braille representation, and interprets the Braille representation to determine the denomination of the bill  14 . 
         [0021]    In a further embodiment, the tactile output device  30  comprises a pressure display capable of generating a unique pressure signal for each denomination of the bill  14  based on the match from the pattern recognizer  22 . For example, the pressure display may comprise a plastic pin or another component that rises and lowers in a unique pattern for each denomination. In one embodiment, the plastic pin or other component rises and lowers a humanly-countable number of times based on the denomination. For example, the plastic pin or other component may rise once for $1, twice slowly for $2, and twice quickly for $20. 
         [0022]    In the audible tone mode, an audible tone generator  32  generates a series of one or more distinctive, non-speech tones associated with the detected denomination of the bill  14 . The user hears the audible tones and determines the denomination of the bill  14  thereon. The audible tone mode provides a degree of security in that other people near the user would not know the denomination of the bill  14  unless they knew how to translate the distinctive tones. The audible tone mode also facilitates use of the reader  10  by users who have limited tactile function. 
         [0023]    In the speech mode, a voice synthesizer  34  generates a voice signal to speak the denomination of the bill  14 . The voice synthesizer  34  may generate the voice signal either by playing back a pre-recorded voice recording or by synthesizing speech. Use of a voice recording allows natural intonated output but requires memory space. Use of synthesized speech is more unnatural, but facilitates programmability and flexibility (e.g. if the voice synthesizer  34  is to be capable of speaking the denomination in multiple languages). While not as secure as the tactile and tone modes, the speech mode requires no learning on the part of the user since the exact denomination rather than a code is given to the user. 
         [0024]    The reader  10  may assume a variety of handheld forms. In one embodiment, the reader  10  is integrated with a mobile telephone. In another embodiment, the reader  10  has the form of a key fob. These and alternative embodiments are beneficial in that the reader  10  can fit in a pocket for carrying by the user. 
         [0025]      FIG. 2  shows an embodiment of the reader  10  integrated with a mobile telephone  40 , and its operation. The digital camera  12  may be provided by the mobile telephone&#39;s camera used for wireless picture messaging applications. The tactile output device  30  may be provided by a vibration alerting device of the mobile telephone  40  that serves to alert of incoming telephone calls and incoming messages. The audible tone generator  32  may be provided by the mobile telephone&#39;s audible ringer that serves to alert of incoming telephone calls and incoming messages. The voice synthesizer  34  may comprise either pre-recorded speech or synthesized speech of “one dollar”, “two dollars”, “five dollars”, “ten dollars”, “twenty dollars”, “fifty dollars” and “one hundred dollars” to output on a speaker of the mobile telephone  40 . Thus, in this embodiment, an individual with low/no vision is enabled to determine the denomination of a bill using his/her wireless camera phone  40 . 
         [0026]      FIG. 2  shows an image  42  of a corner of a bill  44  being acquired using the wireless camera phone  40 . The image  42  is processed through pattern recognition to determine a pattern match based on built-in images  50 ,  52 ,  54 ,  56 ,  58 ,  60  and  62  of $1, $2, $5, $10, $20, $50 and $100 bills, respectively. In the example of  FIG. 2 , the image  42  is matched to the built-in image  62  of the $100 bill. The wireless camera phone  40  reports the bill denomination by an output  64  comprising either a vibration pattern specific to a $100 bill, a tone pattern specific to a $100 bill, or synthesized speech indicating a $100 bill. 
         [0027]      FIG. 3  shows an embodiment of the reader  10  having the form of a key fob  70 . In one embodiment, the key fob  70  houses the components of the reader  10  shown in  FIG. 1 , namely the camera  12 , the button  16 , the optional light source  20 , the pattern recognizer  22 , the memory  24 , the output selector  26 , and at least one of the tactile output device  30 , the audible tone generator  32  and the voice synthesizer  34 . The key fob  70  has superior portability and cost effectiveness. A user can hold the key fob  70  to a corner of the bill  14 , press the button  16 , and receive denomination information through one of the three modes described above. 
         [0028]    It will be apparent to those skilled in the art that the disclosed embodiments may be modified in numerous ways and may assume many embodiments other than the particular forms specifically set out and described herein. 
         [0029]    The above disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments which fall within the true spirit and scope of the present invention. Thus, to the maximum extent allowed by law, the scope of the present invention is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.