Patent Publication Number: US-11036890-B2

Title: System and method for performing biometric operations in parallel using job requests and a plurality of tasks

Description:
RELATED APPLICATION 
     This application is a continuation of U.S. application Ser. No. 15/314,423, filed Nov. 28, 2016, now U.S. Pat. No. 10,331,910, which is a National Stage Application under 35 U.S.C. 371 of PCT Application No. PCT/US2015/031343, filed May 18, 2015, which designated the United States, which PCT application claims the benefit of and priority to U.S. provisional application No. 62/009,516, filed Jun. 9, 2014, titled “System and Method for Performing Biometric Operations in Parallel,” each of which are incorporated in herein by reference in their entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to biometric systems. 
     BACKGROUND 
     Biometrics, broadly defined, is the measurement and analysis of unique physical or behavioral characteristics used to distinguish one individual from another and, thus, to identify or authenticate the identity of individuals. Identification is the process of identifying or detecting the identity of an unknown individual. Authentication is the process of verifying an individual as whom he or she claims to be. Common examples of biometrics used for identification and authentication include fingerprints, irises, retinas, and facial images. 
     The process of identification typically involves comparing a target biometric sample from an unknown individual against a large database of stored biometric information, in search of a match. However, a fingerprint database, for example, can include thousands upon thousands of instances of fingerprint data from a variety of sources. Although computer systems can automate the search, the matching process can run slowly because of several factors, including the sheer number of entries in the database, the nature and quality of the biometric information in the database and of the biometric sample, and the requisite degree of accuracy. 
     SUMMARY 
     All examples and features mentioned below can be combined in any technically possible way. 
     In one aspect, a method of performing a biometric operation is provided. The method comprises receiving a job request to perform a biometric operation. The job request includes input data, identifies a database to be used in the performance of the biometric operation, and specifies a function to be performed. The biometric operation is restructured as one or more tasks. A number of entries in the database is assigned to each of the one or more tasks. An independent worker process is generated for each different core of the multi-core processor. Each task of the one or more tasks is assigned to one of the worker processes. Results produced by each worker process assigned one of the one or more tasks are collected. A result of the biometric operation based on the collected results is reported. 
     Embodiments of the method may include one of the following features, or any combination thereof. 
     Each task may include a plug-in, the function to perform, the input data, and a list of database entries on which to perform the function. The one or more tasks may be a plurality of tasks, and the method may further comprise distributing the plurality of tasks among the worker processes for processing the tasks in parallel. The biometric operation may be to enroll biometric information into the database. The biometric operation may be to perform an identification query based on a biometric sample provided as the input data. 
     The method may further comprise detecting a number of the processor cores at runtime. An aggregate number of entries assigned to the one or more tasks may be all entries or a subset of all entries in the database. 
     The job request may be a map job request to apply a plug-in function across a number of entries in the database, and wherein the biometric operation may be restructured into a plurality of tasks distributed among the worker processes. The job request may be a standard job request, and wherein the biometric operation may be restructured into a single task assigned to one of the worker processes. 
     Assigning each task of the one or more tasks to one of the worker processes may comprise placing each task of the one or more tasks into a queue, removing one task of the one or more tasks from the queue in response to one of the worker processes being available to process the removed task, and assigning the one task removed from the queue to the available worker process. 
     In another aspect, a computer program product is provided for performing a biometric operation comprises a non-transitory computer readable storage medium having computer readable program code embodied therewith. The computer readable program code comprises computer readable program code that, if executed, receives a job request to perform a biometric operation. The job request includes input biometric data, identifies a database to be used in the performance of the biometric operation, and specifies a function to be performed. The computer readable program code further comprises computer readable program code that, if executed, restructures the biometric operation as one or more tasks, computer readable program code that, if executed, assigns a number of entries in the database to each of the one or more tasks, computer readable program code that, if executed, generates an independently executing worker process for each different core of the multi-core processor, computer readable program code that, if executed, assigns each task of the one or more tasks to one of the worker processes, computer readable program code that, if executed, collects results produced by each worker process assigned one of the one or more tasks, and computer readable program code that, if executed, reports a result of the biometric operation based on the collected results. 
     Embodiments of the computer program product may include one of the following features, or any combination thereof. 
     Each task may include a plug-in, the function to perform, the input data, and a list of database entries on which to perform the function. The one or more tasks may be a plurality of tasks, and the method may further comprise distributing the plurality of tasks among the worker processes for processing the tasks in parallel. The biometric operation may be to enroll biometric information into the database. The biometric operation may be to perform an identification query based on a biometric sample provided as the input data. 
     The computer program product may further comprise computer readable program code that, if executed, detects a number of the processor cores at runtime. 
     An aggregate number of entries assigned to the one or more tasks may be all entries or a subset of all entries in the database. 
     The job request may be a map job request to apply a plug-in function across a number of entries in the database, and wherein the biometric operation may be restructured into a plurality of tasks distributed among the worker processes. The job request may be a standard job request, and wherein the biometric operation may be restructured into a single task assigned to one of the worker processes. 
     The computer readable program code that, if executed, assigns a number of entries in the database to each of the one or more tasks may comprise computer readable program code that, if executed, places each task of the one or more tasks into a queue, computer readable program code that, if executed, removes one task of the one or more tasks from the queue in response to one of the worker processes being available to process the removed task, and computer readable program code that, if executed, assigns the one task removed from the queue to the available worker process. 
     In another aspect, a computer system for performing a biometric operation is provided. The computer system comprises memory storing program code used to perform a biometric operation. The program code includes one or more database plugins, one or more biometric operation plugins, and program code that coordinates performance of the biometric operation. The computer system further comprises a multi-core processor executing the program code that coordinates performance of the biometric operation to: receive a job request to perform the biometric operation. The job request includes input biometric data, identifies one of the one or more database plug-ins to be used in the performance of the biometric operation, and specifies a function to be performed. The multi-core processor also executes the program code that coordinates performance of the biometric operation to: restructure the biometric operation as one or more tasks, assign a number of entries in the database to each of the one or more tasks, generate an independently executing worker process for each different core of the multi-core processor, assign each task of the one or more tasks to one of the worker processes, collect results produced by each worker process assigned one of the one or more tasks, and report a result of the biometric operation based on the collected results. 
     Embodiments of the computer system may include one of the following features, or any combination thereof. 
     Each task may include a plug-in, the function to perform, the input data, and a list of database entries on which to perform the function. The one or more tasks may be a plurality of tasks, and the method may further comprise distributing the plurality of tasks among the worker processes for processing the tasks in parallel. The biometric operation may be to enroll biometric information into the database. The biometric operation may be to perform an identification query based on a biometric sample provided as the input data. 
     The program code may detect a number of cores of the multi-core processor at runtime. An aggregate number of entries assigned to the one or more tasks may be all entries or a subset of all entries in the database. 
     The job request may be a map job request to apply a plug-in function across a number of entries in the database, and wherein the biometric operation may be restructured into a plurality of tasks distributed among the worker processes. The job request may be a standard job request, and wherein the biometric operation may be restructured into a single task assigned to one of the worker processes. 
     The multi-processor core may be further programmed to, when assigning each task of the one or more tasks to one of the worker processes: place each task of the one or more tasks into a queue, remove one task of the one or more tasks from the queue in response to one of the worker processes being available to process the removed task, and assign the one task removed from the queue to the available worker process. 
     In still another aspect, a software development kit is provided. The software development kit comprises data processor program code configured to distribute, when executed, performance of a biometric operation across a plurality of cores of a multi-core processor of a computing device, and one or more plugin modules that provide functionality to perform the biometric operation. 
     Embodiments of the software development kit may include one of the following features, or any combination thereof. The software development kit may further comprise one or more plugin modules that provide access to one or more databases, a reference guide providing guidance to a software developer for developing an application program based on the code library and the plug-in modules, one or more samples of application programs that implement the code library, or any combination thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and further advantages of this invention may be better understood by referring to the following description in conjunction with the accompanying drawings, in which like numerals indicate like structural elements and features in various figures. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. 
         FIG. 1  is a block diagram of an embodiment of a computing system programmed to perform biometric operations in parallel. 
         FIG. 2  is a block diagram of an embodiment of a biometric system. 
         FIG. 3  is a flow chart of an embodiment of a process for performing a biometric operation. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows an embodiment of a computing system  10  programmed to perform biometric operations in parallel as described herein. Example implementations of the computing system  10  include, but are not limited to, personal computers (PC), Macintosh computers, server computers, blade servers, workstations, laptop computers, kiosks, network terminals, and hand-held devices, such as a personal digital assistant (PDA), mobile phones, smart phones, and tablets. In general, the computing system  10  is any type of computing machine with a multi-core processor  12 . A multi-core processor, as used herein, is a single computing component having two or more independently operating central processing units or cores. The cores independently read and execute program instructions. Commercially available embodiments of multi-core processors have dual-cores, quad cores, six cores, eight cores, ten cores or more. 
     The multi-core processor  12  is in communication with memory  14  and with an input/output (I/O) interface  16 . The I/O interface  16  is in communication with one or more I/O devices  18 , which include, but are not limited to, a mouse, touch pad, keyboard, display screen, touch screen, a speaker, and a microphone. Although referred to generally as I/O devices, some of such devices may be an input device only (e.g., a keyboard), whereas other devices may be an output device only (e.g., a speaker). A user submits commands and receives results through an I/O device  18 . The I/O interface  16  submits the user commands from the one or more I/O devices  18  to the multi-core processor  12  and returns results to the user through the one or more I/O devices  18 . 
     The memory  14  includes non-volatile computer storage media such as read-only memory (ROM)  20 , volatile computer storage media such as random-access memory (RAM)  22 , and hard-disk memory  24 . Typically stored in the ROM  20  is a basic input/output system (BIOS), which contains program code for controlling the basic operations of the computing system  10 , including start-up of the computing system and initialization of hardware. 
     Stored within the RAM  22  are program code and data. Program code includes, but is not limited to, a software development kit (SDK)  26  comprised of executables  28 , a code library  30 , one or more database plug-ins  32 , and one or more biometric operation plug-ins  34 . Optionally, the SDK  26  can also include one or more samples of application programs  36  demonstrating example use the executables  28  and code library  30 , and a reference guide (e.g., in text or portable document format)  38 . Software developers can use the SDK  26  to construct application programs that perform biometric operations, for example, enrolling biometric images into a database, and running biometric identification searches. Before being stored in the memory  14  of the computing system  10 , the SDK  26  can be embodied in an off-the-shelf product (e.g., CD ROMs) or acquired from a server through an online download. 
     The RAM  22  can also store application programs  40  (e.g., browser), program modules  42  (e.g., browser plug-ins), a native API (e.g., Windows API, MacOS API)  44 , and an operating system  46  (e.g., Windows 95, Windows 98, Windows NT 4.0, Windows XP, Windows 2000, Linux, Macintosh, Windows Mobile™, Mobile Linux™, Symbian OS™, Palm OS™, Mobile OS™, and Android™). 
     The hard disk  24  stores data, for example, biometric templates. Each biometric template represents a biometric measurement of an individual enrolled by a biometric system. A biometric system uses these biometric templates for comparisons against subsequently submitted biometric samples. Biometric samples correspond to a biometric characteristic of an individual as captured by a biometric system. Examples of biometric samples include, but are not limited to, images of fingerprints, irises, and faces. Techniques for converting biometric samples into biometric templates are known in the art. The biometric templates may be aggregated within a database or data store, examples of which include, MongoDB, LevelDB, and Lightning Memory-Mapped Database (LMDB). 
     The executables  28  of the SDK  26  include a data processor utility that runs biometric identification searches and a data processor enroll utility for enrolling biometric images into a database. Hereafter, the data processor utilities are referred to generally as the data processor. The code library  30  includes a shared library (.DLL or .SO) or a static library (.LIB or .a) of program code that provides the core functionality of the data processor. The code library  30  can also include a Java Native Interface (JNI) shared library and a Java jar file that contains the code for using the data processor in Java™. In addition, the code library  30  includes an executable used to launch a worker process. Worker processes independently execute biometric operations; they can execute as separate threads in a single process or as separate processes. 
     The database and biometric operation plug-ins  32 ,  34 , respectively, provide the available functions that the software developer can use when developing an application program. The data processor integrates with databases using the database plug-ins  32 , which enable biometric operations to operate on database data in addition to input data. Each database plug-in  32  provides read and write access to a database of a given type. In one embodiment, the SDK  26  includes a database plug-in for accessing the LMDB database, another database plug-in for accessing the LevelDB database, and yet another database plug-in for accessing the MongoDB database. Other embodiments of the SDK  26  can have fewer or more than these three database types. Biometric operations can be performed on input data only, a single database entry, multiple database entries, or every database entry. In cases where multiple database entries are used, a result is returned for every entry selected. If the biometric operations to be used are all to be performed on input data only, then no database or database plugins need be present. In addition, the functionality of one or more database plug-ins  32  can be involved in the completion of a single biometric operation. 
     Each biometric operation plug-in  34  provides biometric operation functionality. Categories of biometric operation plug-ins can include matcher plug-ins and map plug-ins. Examples of matcher plug-ins include, but are not limited to, a plug-in that provides one-to-one fingerprint comparing, a plug-in that provides one-to-one iris comparing, and a plug-in that provides one-to-one face comparing. In general, a map plug-in provides the ability to perform a function across a database, by taking matcher plug-in functions and applying them concurrently across multiple entries in the database. The functionality of one or more biometric operation plug-ins  34  can be involved in the completion of a single biometric operation. Adding new biometric operations to a biometric system, through the addition of new biometric operation plug-ins, requires no modifications to the data processor or code library  30 . 
       FIG. 2  shows a block diagram of an embodiment of a biometric system  50  comprising a multi-core processor  12  programmed with software  52  for performing user-requested jobs. As used herein, a job is a high-level biometric operation that a user wishes to perform. Examples of high-level biometric operations include, but are not limited to, enrolling biometric data into a database or performing an identify query. 
     In this example embodiment, the multi-core processor  12  has four cores  54 - 1 ,  54 - 2 ,  54 - 3 , and  54 - 4  (generally,  54 ). The principles described herein can extend to any type of multi-core processor having two or more cores. The cores  54  execute code independently and concurrently to provide parallel processing in the performance of the job. 
     The software  52  executed by the multi-core processor  12  includes a data processor process (hereafter, data processor)  56  and worker processes  58 - 1 ,  58 - 2 ,  58 - 3 , and  58 - 4  (generally, worker  58 ). The data processor  56  includes a user interface  60 , a dispatcher  62 , a worker manager  64 - 1 ,  64 - 2 ,  64 - 3 ,  64 - 4  (generally,  64 ), a queue  66 , and one or more results buffers  68 . The software  52  provides a job results buffer  68  for each job currently being performed by the multi-core processor  12 ; all jobs in progress concurrently share the queue  66 . The separate boxes within the data processor  56  represent a logical separation of functionality, although all functions are integrated within the data processor  56 . 
     In general, the data processor  56  is a library that abstracts and executes biometric operations, utilizing the dispatcher  62 , worker managers  64 , and queue  66  to deliver tasks to workers  58 . As used herein, a task is a low-level biometric operation to be performed. Examples of tasks include, but are not limited to, compressing a bitmap image file (BMP) fingerprint image to a Wavelet Scalar Quantization (WSQ) fingerprint image or performing a match using a matcher plug-in with two input images. When multiple workers  58  execute, multiple tasks can be performed in parallel. 
     Each worker  58  is program code that can independently execute biometric operations, continuously waiting until a task becomes available on the common queue  66 , then obtaining ownership and executing that task. The workers  58  can be part of the same process as the dispatcher  62  as threads or each worker  58  can be a separate process. Where each worker  58  resides in a separate process, each worker  58  has an associated worker manager process  64  that directly pulls a task off the queue  66  and then sends the task to the worker  58 . The worker  58  receives and performs the task and then returns the results to its associated worker manager  64 . 
     Each worker  58  is also in communication with one or more database plug-in interfaces  72  and with one or more biometric operation plug-in interfaces  70 . Worker functionality is acquired from the database and biometric operation plug-ins  32 ,  34 , respectively. Through a database plug-in interface  72 , each worker  58  is able to incorporate the functionality of a given database plug-in  32 . Through a biometric operation plug-in interface  70 , each worker  58  is able to incorporate the functionality of a given biometric operation plug-in  34 . Each database and biometric operation plug-in  32 ,  34 , respectively, reports whether a given performed function was valid or whether any other errors were encountered. 
     The number of workers  58  used by the data processor  56  is configured by the software developer using the data processor  56 . This number can be an explicitly declared (e.g., 2, 5, 10). Alternatively, the data processor  56  can automatically detect the number of cores  54  available at runtime using standard library functionality (e.g., C++) to determine the number of cores, and, correspondingly, the number of workers  58  to launch. 
     The user interface  60  is in communication with the user to receive job requests and input data (e.g., a biometric sample) and to provide the results of the job to the user. A biometric reader, for example, a fingerprint reader, can supply the input data. 
     The dispatcher  62  is in communication with the user interface  60  to obtain the user-supplied instructions and input data. In addition, the dispatcher  62  is in communication with the queue  66  upon which the dispatcher  62  places tasks to be performed by the workers  58 . Further, the dispatcher  62  is in communication with the results buffer  68  of each job from which the dispatcher  62  collects the separate results produced by each of the workers  58  performing their assigned tasks and compiles the results of the job for forwarding to the user. 
     Each worker manager  64  is associated with one of the worker processes  58  and in communication with the queue  66  and with the results buffer  68 . Each worker manager  64  removes a task from the queue  66  when its associated worker  58  is available, and passes that task to that worker  58 . When that worker  58  completes the assigned task, the results return to its associated worker manager  64 . The worker manager  64  then places the results of the task into the appropriate results buffer  68  (i.e., associated with the job for which the task is performed) for subsequent collection by the dispatcher  62 . 
       FIG. 3  shows an embodiment of a process  100  for performing a biometric operation, using the multiple cores of the multi-core processor  12  to process tasks associated with one or more jobs in parallel. In the description of the process  100 , reference is made to elements shown in  FIG. 1  and  FIG. 2 . At step  102 , the user runs an application program developed from the SDK  26  and configured to perform a desired biometric operation. Through the user interface  60 , the data processor  56  receives (step  104 ) user input requesting performance of a job, the user input including a biometric sample, which may be obtained through a biometric reader, and specifying the desired biometric operation. A user may request more than one job (as represented by dashed arrow  105 ), to be performed concurrently. 
     The data processor  56  can accept (step  106 ) two types of jobs from the user: a standard job; and a map job. A standard job includes the desired biometric operation plug-in  34  or database plug-in  32 , the function to run, and the input data for the function. The data processor  56  turns (step  108 ) a standard job into a single task and the dispatcher  62  places (step  110 ) the task into the queue  66  for a worker  58  to run. If multiple standard jobs are to run concurrently, the data processor  56  can take advantage of the parallel processing capabilities of the multi-core processor  12 , distributing the multiple single standard jobs (turned into single tasks) across the workers  58 . As an example, the user can request a standard job to enroll a biometric sample in a MongoDB database. In response, the data processor (i.e., enroll utility)  56  produces a single task, specifying the enroll function, the MongoDB database plug-in  32 , and providing the biometric sample to be enrolled. 
     A map job acquires its “map” name as a reference to the general programming concept map, which applies a single function to a list of items. In the biometric system  50 , a map job specifically refers to applying a biometric operation plug-in function across a number of database entries, which either can be the entire database or a selected subset of the database. The data processor  56  generates (step  112 ) multiple tasks by splitting up the list of applicable database entries, and the dispatcher  62  places (step  114 ) each task into the queue  66 . Each task contains a desired biometric operation plug-in  34 , a function to run, input biometric data, and a database plugin with a list of database entries on which to perform the function. The list of database entries that accompanies each task can be one or more entries. As an example, the user can request a map job to identify an individual associated with a biometric sample. In response, the data processor  56  produces a multiple tasks, specifying a matcher biometric operation plug-in  34 , a matcher function, and the LevelDB database plug-in  32 , providing the biometric sample to be matched and a different list of database entries with which to compare the biometric sample. 
     At step  116 , a worker manager  64  removes a task from the queue  66  and dispatches the task to its associated worker  58  ready (available) to perform a task. The current jobs, if more than one, share queue  66 . Each worker  58  is associated with a different one of the cores  54  of the multi-core processor  12 . The cores  54  work in parallel, each executing the function associated with the task assigned to its associated worker  58  in accordance with the functionality provided by the associated database and biometric operation plug-ins  32 ,  34 , respectively. The assigning of tasks to workers  58 , as workers become available, can attain a substantially balanced distribution of the workload among the workers  58  and, thus, efficiently employ the cores  54  throughout the execution of each job. 
     At step  118 , each worker manager  64  places the results of the task performed by its associated worker  58  into the results buffer  68 . Each job has its own associated results buffer  68 ; and the task results are placed in the appropriate results buffer  68 . After a task result is added to a job result buffer  68 , the dispatcher  62  decides (step  120 ) whether to report results to the user for that particular job. The decision is affirmative if one or both of the following conditions are true: 1) all tasks associated with the job are completed, hence, the job is complete; 2) a threshold number of tasks, out of the total number of tasks for the job, have been completed. Normally, some tasks for the particular job remain to be done when the threshold is reached. This threshold number is configurable by the user. If both conditions are unsatisfied, the process  100  continues dispatching (step  116 ) tasks from the task queue  66 . 
     When a particular job is complete or when a threshold number of task results has been collected for the job, the dispatcher  62  acquires the results (partial or full) from the results buffer  68  associated with the job and sends (step  122 ) those results to the user. The data processor  56  presents the partial or full outcome of the job to the user through the user interface  60 . 
     If, at step  124 , the queue  66  contains tasks, the process  100  continues by dispatching (step  116 ) one of the queued tasks to an available worker  58 . For instance, in the event the dispatcher  62  reports partial results, the queue  66  still holds at least those tasks remaining for the partially completed job. In addition, the queue  66  may contain tasks associated with other jobs not yet completed. If, instead, at step  124 , the queue  66  is empty, all submitted jobs are complete; the process  100  is done. 
     In addition to making efficient use of the multi-core processor  12  during the performance of the job, the data processor  56  can also make efficient use of the memory  14 . For example, certain biometric operations, such as a biometric identification search, can occur in stages. In a biometric identification search, an input biometric sample is compared with a database containing a large number of biometric templates. A first stage of the search quickly compares the input biometric sample with all of the candidate biometric templates, sacrificing accuracy in order to reduce the large number of candidate biometric templates to a lesser number. A second stage and, optionally, a third stage operate progressively slower than their previous stage, performing a progressively more time consuming and accurate comparison than their previous stage, while progressively reducing the number of candidate biometric templates that remain as possible matches to the input biometric sample. A final stage can be the slowest but most accurate of all the stages, searching through the fewest candidate biometric templates in search of a match. 
     The number of stages in a biometric operation is configurable, and can be determined by a particular biometric operation plug-in  34 . A single biometric operation plug-in  34  can provide the functionality of all stages, or different biometric operation plug-ins  34  can provide the functionality of a different stage or a different subset of stages. In general, the stages run in serial; the first stage completes before the second stage can begin. Alternatively, there can be some overlap between the executions of the stages; the second stage can begin as soon as the first stage identifies a potential match and can execute its function while the first stage continues to search through the candidate biometric templates. In this instance, the cores  54  of the multi-core processor  12  may be working concurrently on tasks associated with different stages of the biometric operation. 
     In general, the gallery of biometric templates resides on the hard disk  24 , which has memory accesses that are considerably slower than those to RAM  22 . When a database of biometric templates initializes, a small number of the biometric templates can be preloaded from the hard disk  24  to the RAM  22 . The remaining biometric templates can remain on the hard disk  24 . For the first stage of the biometric identification search, which processes the greatest number of biometric templates of all the stages, the candidate biometric templates can be loaded from hard disk  24  to RAM  22 , in advance of being needed by a worker  58 . For each of the later stages, which work with progressively fewer candidate biometric templates than an earlier stage, the biometric templates can remain on the hard disk  24  until a worker  58  requires the biometric template for a comparison, at which point the memory access is made to the hard disk  24 . 
     As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a system, method, and computer program product. Thus, aspects of the present invention may be embodied entirely in hardware, entirely in software (including, but not limited to, firmware, program code, resident software, microcode), or in a combination of hardware and software. All such embodiments may generally be referred to herein as a circuit, a module, or a system. In addition, aspects of the present invention may be in the form of a computer program product embodied in one or more computer readable media having computer readable program code embodied thereon. 
     The computer readable medium may be a computer readable storage medium, examples of which include, but are not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination thereof. As used herein, a computer readable storage medium may be any non-transitory, tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, device, computer, computing system, computer system, or any programmable machine or device that inputs, processes, and outputs instructions, commands, or data. A non-exhaustive list of specific examples of a computer readable storage medium include an electrical connection having one or more wires, a portable computer diskette, a floppy disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), a USB flash drive, an non-volatile RAM (NVRAM or NOVRAM), an erasable programmable read-only memory (EPROM or Flash memory), a flash memory card, an electrically erasable programmable read-only memory (EEPROM), an optical fiber, a portable compact disc read-only memory (CD-ROM), a DVD-ROM, an optical storage device, a magnetic storage device, or any suitable combination thereof. A computer readable storage medium can be any computer readable medium that is not a computer readable signal medium such as a propagated data signal with computer readable program code embodied therein. 
     Program code may be embodied as computer-readable instructions stored on or in a computer readable storage medium as, for example, source code, object code, interpretive code, executable code, or combinations thereof. Any standard or proprietary, programming or interpretive language can be used to produce the computer-executable instructions. Examples of such languages include C, C++, Pascal, JAVA, BASIC, Smalltalk, Visual Basic, and Visual C++. 
     Transmission of program code embodied on a computer readable medium can occur using any appropriate medium including, but not limited to, wireless, wired, optical fiber cable, radio frequency (RF), or any suitable combination thereof. 
     The program code may execute entirely on a user&#39;s computer, partly on the user&#39;s computer, as a stand-alone software package, partly on the user&#39;s computer and partly on a remote computer or entirely on a remote computer or server. Any such remote computer may be connected to the user&#39;s computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). 
     Additionally, the methods of this invention can be implemented on a special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit element(s), an ASIC or other integrated circuit, a digital signal processor, a hard-wired electronic or logic circuit such as discrete element circuit, a programmable logic device such as PLD, PLA, FPGA, PAL, or the like. 
     Furthermore, the disclosed methods may be readily implemented in software using object or object-oriented software development environments that provide portable source code that can be used on a variety of computer or workstation platforms. Alternatively, the disclosed system may be implemented partially or fully in hardware using standard logic circuits or a VLSI design. Whether software or hardware is used to implement the systems in accordance with this invention is dependent on the speed and/or efficiency requirements of the system, the particular function, and the particular software or hardware systems or microprocessor or microcomputer systems being utilized. The methods illustrated herein however can be readily implemented in hardware and/or software using any known or later developed systems or structures, devices and/or software by those of ordinary skill in the applicable art from the functional description provided herein and with a general basic knowledge of the computer and image processing arts. 
     Moreover, the disclosed methods may be readily implemented in software executed on programmed general-purpose computer, a special purpose computer, a microprocessor, or the like. In these instances, the systems and methods of this invention can be implemented as program embedded on personal computer such as JAVA® or CGI script, as a resource residing on a server or graphics workstation, as a routine embedded in a dedicated fingerprint processing system, as a plug-in, or the like. The system can also be implemented by physically incorporating the system and method into a software and/or hardware system, such as the hardware and software systems of an image processor. 
     While this invention has been described in conjunction with a number of embodiments, it is evident that many alternatives, modifications and variations would be or are apparent to those of ordinary skill in the applicable arts. Accordingly, it is intended to embrace all such alternatives, modifications, equivalents, and variations that are within the spirit and scope of this invention.