Methods and systems of authentication

A method of authentication is provided that includes capturing palm biometric data from an individual, transmitting the biometric data to an authentication system, and generating an authentication biometric template from the captured biometric data with the authentication system. Moreover, the method includes conducting a plurality of verification matching transactions between the authentication biometric template and enrollment biometric templates stored in the authentication system, and between the authentication biometric template and imposter biometric templates stored in the authentication system. Furthermore, the method includes updating a genuine matching score distribution with at least one genuine matching score, updating an imposter matching score distribution with at least one imposter matching score, and calculating a maximum genuine matching score and a minimum imposter matching score. Additionally, the method includes confirming an identity of the individual when the minimum imposter matching score is greater than the maximum genuine matching score.

BACKGROUND OF THE INVENTION

This invention relates generally to methods and systems that facilitate authenticating individuals, and more particularly, to methods and systems of authentication based on matching score distributions.

Known palm biometric data capture devices typically include a platen and an instrument positioned at a fixed distance from the platen. When a palm is placed on the platen such that the fingers are fully extended and in a known orientation, a high resolution palm image may be captured and the size of the palm accurately determined.

However, known palm biometric data capture devices are generally large and cumbersome. Thus, known palm biometric data capture devices are not typically portable. Moreover, such devices are not known to be readily available to the general public, thus, accessing such devices is inconvenient and time consuming for members of the general public. Furthermore, such devices have been known to be expensive. Additionally, because known devices require palm placement on the platen in a known orientation and at a known distance from the capture sensor, palm biometric data is not captured from a hand positioned freely in space.

Capturing palm biometric data for authentication with a device from a hand positioned freely in space has been known to be difficult because, due to folds and curves in the palm, palm biometric data captured at different times may present widely varying sets of palm features. Moreover, it has been observed that palm biometric data captured from a hand positioned freely in space, with a device, is generally captured at different orientations and at different angles relative to the device. Thus, it has been known that palm biometric data captured from a hand positioned freely in space is not typically reliable biometric data that may be used for accurate authentication.

BRIEF DESCRIPTION OF THE INVENTION

In one aspect, a method of authentication is provided that includes capturing palm biometric data with a device from an individual, transmitting the captured biometric data to a biometric authentication system, and generating an authentication biometric template from the captured biometric data with the biometric authentication system. Moreover, the method includes conducting a plurality of verification matching transactions between the authentication biometric template and enrollment biometric templates stored in the biometric authentication system, and between the authentication biometric template and imposter biometric templates stored in the biometric authentication system. The enrollment biometric templates and imposter templates are associated with the individual in the biometric authentication system, and the imposter biometric templates are generated from biometric data obtained from known imposters. Furthermore, the method includes updating a genuine matching score distribution with at least one genuine matching score generated during the conducting operation, updating an imposter matching score distribution with at least one imposter matching score generated during said conducting operation, and calculating a maximum genuine matching score and a minimum imposter matching score. Additionally, the method includes determining whether the minimum imposter matching score is greater than the maximum genuine matching score, and confirming an identity of the individual when the minimum imposter matching score is greater than the maximum genuine matching score.

In another aspect, a system for conducting matching transactions is provided that includes an authentication system including an authentication database. The authentication system is configured to communicate with devices and to store within the database authentication data for a plurality of individuals, matching scores, and matching score distributions. The system also includes a device configured to communicate with at least the authentication system and to capture biometric data positioned freely with respect to the device. The authentication system is further configured to generate an authentication biometric template from captured biometric data, and conduct matching transactions between the authentication biometric template and enrollment biometric templates stored therein, and between the authentication biometric template and imposter biometric templates stored therein. Moreover, the authentication system is configured to generate a genuine matching score distribution and an imposter matching score distribution, and calculate a maximum genuine matching score and a minimum imposter matching score. Furthermore, the authentication system is further configured to confirm an identity of an individual associated with the captured biometric data when the minimum imposter matching score is greater than the maximum genuine matching score.

In yet another aspect, a method of authentication is provided that includes generating a genuine matching score distribution and an imposter matching score distribution with a biometric authentication system. Moreover, the method includes conducting matching transactions between an authentication biometric template and enrollment biometric templates and between the authentication biometric template and imposter biometric templates. The authentication biometric template is generated from palm biometric data of an individual. Furthermore, the method includes updating the matching score distribution and the imposter score distribution with results generated during the conducting operation, determining whether a minimum imposter matching score is greater than a maximum genuine matching score, and confirming an identity of the individual when the minimum imposter score is greater than the maximum genuine matching score.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1is an expanded block diagram of an exemplary embodiment of a system architecture of an Authentication Computer (AC) System10for authenticating the identity of a user. More specifically, the AC system10includes a Biometric Authentication Computer (BAC) System12and a device14.

The BAC system12includes components such as, but not limited to, a web server, a disk storage device, a database management server and an authentication server arranged to be combined into a single structure. Although these components are combined into a single structure in the exemplary embodiment, it should be appreciated that in other embodiments these components may be separately positioned at different locations and operatively coupled together in a network such as, but not limited to, a local area network (LAN), a wide area network (WAN) and the Internet. The disk storage device may be used for storing any kind of data including, but not limited to, biometric data, results of filtering analyses, scale factors, coordinates, correlation factors, matching scores, and matching score distributions. The database management server may be used to facilitate transferring data to and from the disk storage device. The authentication server is configured to at least perform matching of any feature or information associated with individuals to authenticate the identity of individuals as described herein.

The BAC system12is configured to wirelessly communicate with the device14over a communications network16in the exemplary embodiment. Moreover, the BAC system12is operable to communicate with other computer systems (not shown) over a network (not shown) such as, but not limited to, a local area network (LAN), a wide area network (WAN) and the Internet. In the exemplary embodiment, the communications network16is a 3 G communications network. However, it should be appreciated that in other embodiments the communications network16may be any network that facilitates authentication as described herein, such as, but not limited to, Wi-Fi, Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), Enhanced Data for GSM Environment (EDGE), a LAN, a WAN and the Internet.

The BAC system12is also operable to store biometric data and to conduct authentication matching transactions with biometric data. Specifically, in the exemplary embodiment, biometric data that may be used as the basis of authentication is captured from individuals during enrollment and is stored in the BAC system12. The biometric data may take any form such as, but not limited to, images, photographs, templates and electronic data representations. Using biometrics as the basis for authentication facilitates enhancing trust in authentication matching transaction results.

The BAC system12stores the biometric data of each individual captured during enrollment in respective enrollment data records. The captured biometric data corresponds to a biometric modality desired for conducting authentication transactions. In the exemplary embodiment, the desired biometric modality is the palm of a right hand. However, in other embodiments the palm biometric data may be from the left hand. In yet other embodiments the biometric data desired for conducting authentication transactions may correspond to any other biometric modality that facilitates authentication as described herein. Such other biometric modalities include, but are not limited to, hand geometry, foot, face, iris, vascular patterns and hand signatures.

The captured biometric data for each individual is processed during enrollment to generate an enrollment biometric template, for each respective individual, which is used by the BAC system12to conduct authentication matching transactions. In the exemplary embodiment, each enrollment data record includes at least the captured biometric data and the enrollment biometric template of a respective individual. Moreover, an outline image is generated for each individual and included in the respective enrollment data record. In other embodiments each enrollment data record may also include any kind of data that may be used in authentication. Such data includes, but is not limited to, biographic data, biometric data for biometric modalities different than the biometric modality desired for conducting authentication transactions, and any combination of biometric modality data. The term “biographic data” as used herein includes any demographic information regarding an individual such as, but not limited to, an individual's name, age, date of birth, address, citizenship and marital status.

The BAC system12also stores imposter biometric templates. During authentication matching transactions an authentication biometric template generated for an individual to be authenticated may be compared against at least one enrollment biometric template of the individual, and against at least one biometric template associated with at least one known different individual. The at least one different individual is considered to be a known imposter during an authentication matching transaction because he is not the individual to be authenticated. Thus, the biometric template of a known imposter is referred to herein as an imposter biometric template. Consequently, it should be understood that imposter biometric templates are biometric templates that do not originate from an individual to be authenticated. Each imposter biometric template is generated through the same process described in the exemplary embodiment used to generate the enrollment biometric templates.

In the exemplary embodiment, biometric features are extracted from the captured biometric data by the BAC system12and are included as data in the enrollment biometric template generated by the BAC system12. The enrollment biometric templates are a compact representation of the biometric features included in the captured biometric data, and are used for authenticating individuals. Although captured biometric data for each individual is stored in the BAC system12in the exemplary embodiment, in other embodiments the captured biometric data may be stored in a server system different than the BAC system12.

Although the biometric data is captured from individuals during enrollment in the BAC system12, it should be appreciated that in other embodiments the biometric data may be obtained by any other method including, but not limited to, automatically reading or extracting the biometric data from identity documents or from legacy data bases included in other computer systems. Likewise, biometric templates and outline images corresponding to the biometric data may be obtained by any method including, but not limited to, automatically reading or extracting the biometric templates and outline images from identity documents or from legacy data bases included in other computer systems. It should be understood that biometric templates and outline images corresponding to desired biometric data may be obtained in addition to, or instead of, the desired biometric data. Such other legacy database systems include, but are not limited to, systems associated with motor vehicle administrations, social security administrations, welfare system administrations, financial institutions and health care providers. Such identity documents include, but are not limited to, passports and driver's licenses. It should be appreciated that by extracting desired biometric data, or biometric templates and outline images, from a legacy database or identity document, and storing the extracted data in the BAC system12, individuals may be enrolled therein without having to provide biometric data.

Moreover, the BAC system12stores authentication policies therein which are used to determine data that is to be captured or obtained from an individual attempting to enroll in the BAC system12. Furthermore, additional authentication policies may be stored in the BAC system12that determine data to be captured from an individual requesting biometric authentication.

The BAC system12is also operable to at least conduct any type of matching transaction, process biometric data into an outline image, and determine transformations and scale factors. Moreover, the BAC system12is operable to calculate at least coordinates, correlation factors, false match rates, false non-match rates, matching scores, and equal error rates. Furthermore, the BAC system12is operable to generate matching score distributions from matching scores. A matching score distribution is a function of matching scores that represents the frequency of a given matching score in a collection of matching scores. A genuine matching score distribution is a matching score distribution in which all matching scores are obtained by matching a biometric template against another biometric template that is known, or believed, to belong to the same biometric of the same individual and obtained at a different instance. An imposter matching score distribution is a matching score distribution in which all matching scores are obtained by matching a biometric template against another biometric template that is known, or believed, to belong to the same biometric of a different individual or a different biometric of the same individual.

The device14includes at least one of buttons and icons18operable to at least enter commands, enter data and invoke applications stored therein. Moreover, the device14includes a display screen20such as, but not limited to, a Liquid Crystal Display (LCD), and is operable to display any text or image on the display screen20. In the exemplary embodiment, the device14is a smart phone operable to at least display messages and images, capture biometric data, and transmit the captured biometric data to the BAC system12. By virtue of being a smart phone the device14is portable in the exemplary embodiment. However, in other embodiments the device14may not be portable.

Although the device14is a smart phone in the exemplary embodiment, it should be appreciated that in other embodiments the device14may be any device capable of at least communicating with the BAC system12, displaying messages and images, and capturing and processing biometric data, and transmitting data. Such other devices14include, but are not limited to, a tablet computer, a television, a camera, a personal desktop computer, a laptop computer, and a personal digital assistant (PDA). Since each of the listed devices may communicate with other devices, the device14may also be described as a communications device.

The device14is configured to wirelessly communicate with at least the BAC system12over the network16. Moreover, in the exemplary embodiment the device14is used to capture biometric data from individuals. Specifically, a security application is stored in the device14that facilitates capturing biometric data with the device14during enrollment and authentication. When an individual decides to capture biometric data, the security application is invoked by activating a button or icon18. It should be understood that an operator may invoke the security application and otherwise operate the device14during enrollment and authentication. The operator may be the individual offering biometric data for capture during enrollment or authentication, or may be a user different than the individual. After invoking the security application during enrollment, the security application causes the device14to display a biometric data capture request message in the display screen20prompting the user to capture desired biometric data. After biometric data in accordance with the capture request message is captured with the device14, the security application causes the device14to transmit the captured biometric data to the BAC system12. In the exemplary embodiment the security application also causes the device14to display outline images. In other embodiments after capturing the desired biometric data with the device14, the security application may cause the device14to process the captured biometric data into an outline image and transmit both the captured biometric data and outline image to the BAC system12. The device14does not store the captured biometric data therein and does not store biometric templates and outline images generated therefrom therein.

The memories (not shown) in the BAC12and the device14can be implemented using any appropriate combination of alterable, volatile or non-volatile memory or non-alterable, or fixed, memory. The alterable memory, whether volatile or non-volatile, can be implemented using any one or more of static or dynamic RAM (Random Access Memory), a floppy disc and disc drive, a writeable or re-writeable optical disc and disc drive, a hard drive, flash memory or the like. Similarly, the non-alterable or fixed memory can be implemented using any one or more of ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), an optical ROM disc, such as a CD-ROM or DVD-ROM disc, and disc drive or the like.

Each memory (not shown) can be a computer-readable recording medium used to store data in the BAC system12and the device14, and store computer programs, applications, or executable instructions that are executed by the BAC system12and the device14. Moreover, the memory (not shown) may include smart cards, SIMs or any other medium from which a computing device can read computer programs or executable instructions. As used herein, the terms “computer program” and “application” are intended to encompass an executable program that exists permanently or temporarily on any computer-readable recordable medium that causes the computer or computer processor to execute the program.

FIG. 2is a plan view of an exemplary enrollment hand image22captured with the device14during enrollment in the BAC system12. The enrollment hand image22includes a right hand24that includes biometric features26which in the exemplary embodiment are lines and wrinkles However, in other embodiments the biometric features26may be any biometric feature including, but not limited to, ridge lines. It should be understood that the enrollment hand image22is rectangular-shaped, includes a center point28, is digital, and is positioned on a first Cartesian coordinate system that includes an X-axis and a Y-axis.

It should be understood that digital images include an array of pixels and that each pixel occupies a position within the array. Thus, the position of each pixel within a digital image positioned on a Cartesian coordinate system is determined by the coordinates of the Cartesian coordinate system. Because the enrollment hand image22is digital and is positioned on the first Cartesian coordinate system, the positions of pixels within the enrollment hand image22are defined by the first Cartesian coordinate system.

FIG. 3is the plan view of the exemplary enrollment hand image22as shown inFIG. 2, further including an enrollment region of interest30positioned mostly on the palm area of the hand24. In the exemplary embodiment, the enrollment region of interest30is square-shaped. However, in other embodiments the enrollment region of interest30may have any shape including, but not limited to, rectangle and circle. The enrollment region of interest30is positioned on a second Cartesian coordinate system that includes an X′-axis and a Y′-axis. The enrollment region of interest30defines part of biometric data captured during enrollment that is to be included in an enrollment biometric template for use during authentication. Because the region of interest30is positioned on the hand24to include mostly the palm portion of the hand24, palm biometric data is to be used for authentication in the exemplary embodiment.

FIG. 4is the plan view of the enrollment hand image22as shown inFIG. 3, further including a best fit line32for use in constructing the enrollment region of interest30. In the exemplary embodiment, the enrollment region of interest30is constructed by first calculating coordinates of points34,36,38in accordance with the first Cartesian system. Points34,36,38are each positioned at the base between different fingers. Next, constructing the enrollment region of interest30continues by determining the line32that constitutes a best fit between points34,36,38, and determining a normal projection from each point34,36,38to the best fit line32. Each normal projection intersects the best fit line32to define further points40,42,44, respectively. The coordinates of points40,42,44are calculated in accordance with the first Cartesian coordinate system. A distance D is determined between points40and44that may be referred to as a scale identifying number or a scale factor. Next, the coordinates of a midpoint MP between points40and44are calculated in accordance with the first Cartesian coordinate system, and a vector v1parallel to the best fit line32and a vector v2normal to the best fit line32are determined. The scale identifying number D, the coordinates of the midpoint MP, and the vectors v1and v2are then substituted into an equation Pi=MP+a1Dv1+b1Dv2to calculate the coordinates of each corner of the region of interest30. The designation “i” as used in conjunction with the corner points Pi, is intended to indicate that any number “i” of corner points, appropriate for any geometric shape, may be used that facilitates authentication as described herein. It should be appreciated that a1and b1designate coefficients that facilitate calculating the coordinates of corner points Pi. By virtue of determining the coordinates of points Pi, in accordance with the first Cartesian coordinate system, it should be appreciated that the enrollment region of interest30is defined.

Although the exemplary embodiment determines the enrollment region of interest30by calculating the coordinates of each corner using an equation, it should be appreciated that differently shaped enrollment regions of interest30may be determined using other methods, equations or mathematical relationships.

FIG. 5is the plan view of the exemplary enrollment hand image22as shown inFIG. 3, further including a patch area46. In the exemplary embodiment, the patch area46is rectangular-shaped, has a fixed size that is smaller than the enrollment region of interest30, and is positioned at a center of gravity of the hand24. It should be understood that the patch area46is not merely a rectangular geometric shape superimposed on the hand24. Rather, the patch area46represents a copy of a portion of the enrollment hand image22within the bounds of the patch area46. The coordinates of the center of gravity of the hand are calculated in accordance with the second Cartesian coordinate system. Next, the center of the patch area46is positioned to be coincident with the center of gravity. Thus, after positioning the center of the patch area46on the center of gravity, the center of the patch area46has the same coordinates as the center of gravity of the hand24. In the exemplary embodiment sides of the patch area46are parallel to the sides of the enrollment region of interest30. However, in other embodiments it is not necessary that the sides of the patch area46be parallel to the sides of the enrollment region of interest30.

It should be understood that the position of the enrollment region of interest30and the position of the patch area46are not related. However, the patch area46is to be positioned completely within the enrollment region of interest30. Although the patch area is rectangular-shaped in the exemplary embodiment, in other embodiments the patch area46may be any shape including, but not limited to, square and circle. Moreover, in other embodiments instead of positioning the center of the patch area46coincident with the center of gravity of the hand24, the patch area46may be positioned at areas on the hand24within the enrollment region of interest30that have a higher density of biometric features than other areas. A biometric template of the patch area46and an enrollment biometric template of the portion of hand24within the enrollment region of interest30are generated by the BAC system12and stored therein. Because the region of interest30is positioned on the hand24to include mostly the palm portion of the hand24, by thus generating the enrollment biometric template palm biometric data is considered to have been captured such that biometric authentication based on palm biometric data may be conducted.

FIG. 6is a plan view of an exemplary outline image48of the hand24that is generated by the BAC system12from the enrollment hand image22in the exemplary embodiment. However, in other embodiments the outline image48may be generated by the device14.

FIG. 7is a flowchart50illustrating an exemplary process for generating the outline image48from the enrollment hand image22during enrollment in the BAC system12. Specifically, the generating process starts52by capturing desired biometric data54from an enrolling individual with the device54and transmitting the captured biometric data to the BAC system12. In the exemplary embodiment, the desired biometric data is the palm side of the right hand. The BAC system12continues processing by generating54the enrollment hand image22from the captured hand biometric data, and converting the enrollment hand image22into a gray scale hand image.

Next, processing continues by conducting a first stage of filtering56. Specifically, processing continues by filtering the gray scale hand image with a first filter and with a second filter. As a result, the first filter generates a first digital image and the second filter generates a second digital image. Next, processing continues by determining an average image of the first and second images which is referred to herein as a first average image. Because the first and second images are digital images, the first average image is also a digital image.

Next, processing continues by conducting a second stage of filtering58. Specifically, processing continues by rotating the gray scale hand image about the center point28clockwise by forty-five degrees and filtering the rotated gray scale hand image with the first filter and with the second filter. As a result, the first filter generates a first rotated digital image and the second filter generates a second rotated digital image. Processing continues by determining an average image of the first and second rotated images which is referred to herein as a second average image. Because the first and second rotated images are rotated digital images of the gray scale hand image, the second average image is also a rotated digital image of the gray scale hand image. In the exemplary embodiment, the first and second filters are different Sobel filters. However, in other embodiments any type of edge detection filter may be used that facilitates generating the outline image48as described herein. Moreover, in yet other embodiments any process may be used that facilitates generating the outline image48including, but not limited to, conducting statistical color analysis, clustering, and any combination of such processes with each other or in concert with conducting edge detection using edge detection filters.

Next, processing continues by combining the first and second average images60to form a combined average digital image. Specifically, processing continues by rotating the second average image about the center point28counterclockwise by forty-five degrees and determining the intensity of each pixel included in the first average image and in the second average image. Each pixel in the first average image has a corresponding pixel in the second average image. Corresponding pixels in the first and second average images have the same coordinates and constitute a pair of pixels. Each pair of pixels is compared against a range of intensities that includes a low intensity range, a middle intensity range, and a high intensity range. When at least one of the pixels included in each pair has an intensity in the middle intensity range, a pixel in the combined average image corresponding to each pixel of the pair, is set to a positive non-zero value of 255. Otherwise, the combined average image pixel corresponding to each pixel of the pair is set to zero.

After combining the average images60to form the combined average image, processing continues by filtering the combined average image62with a smoothing filter. In the exemplary embodiment the smoothing filter is a Gaussian function having a standard deviation of one. However, in other embodiments any filter may be used that facilitates determining the outline image48as described herein. A smoothed combined average image is generated as the result of the filtering operation62. Processing continues by converting the smoothed combined average image into a binary image. Specifically, processing continues by determining the intensity64of each pixel in the smoothed combined average image. Each pixel in the smoothed combined average image having an intensity below a mid-point value of 128 is given a value of zero. All other pixels in the smoothed combined average image are given a value of one. By thus giving each pixel in the smoothed combined average image a value of zero or one, the smoothed combined average image is converted into a binary image that represents a preliminary outline image of the right hand24.

Next, processing continues by eliminating noise66from the preliminary outline image. Specifically, processing continues by determining four-connected sets of pixels within the preliminary outline image and determining a population of each four-connected set of pixels. When the population of a four-connected set of pixels is less than a threshold value, each pixel included in the four-connected set of pixels is given a value of zero. Otherwise, when the population of a four-connected set of pixels is at least equal to the threshold value, each pixel value included in the four connected set of pixels remains unchanged.

After eliminating noise66from the preliminary outline image, processing continues by expanding each non-zero value pixel68included in the preliminary outline image by a predetermined width in both the X and Y directions of the first Cartesian coordinate system. Doing so, facilitates enhancing the visibility of the preliminary outline image and thus results in the outline image48of the right hand24. Processing continues by storing70the outline image48in the BAC system12. Next, processing ends72.

Although the outline image48is stored in the BAC system12after expanding each non-zero value pixel in the exemplary embodiment, in other embodiments after expanding each non-zero value pixel processing may continue by transmitting the captured biometric data and outline image48to the device14, and displaying the captured biometric data and outline image48on the display screen20. The operator continues processing by reviewing the outline image48for correctness and confirms that the outline image48is correct by activating a button or icon18. For example, the operator may confirm that the outline image48includes the correct number of fingers. After confirming that the outline image48is correct, processing continues by transmitting the captured biometric data and outline image48to the BAC system12for storage therein. When the outline image48is not confirmed as correct, processing may continue by again capturing biometric data at operation54. Otherwise, processing ends72.

Although the BAC system12generates the outline image48in the exemplary embodiment, in other embodiments upon capturing the biometric data, the device14may generate the outline image48and transmit the outline image48and captured biometric data to the BAC system12. In such other embodiments, upon generating the outline image48the device14may continue processing by presenting the outline image and captured biometric data on the display screen20for review by the operator. After confirming that the outline image is correct, processing may continue by transmitting the captured biometric data and outline image48to the BAC system12for storage therein. Such other embodiments avoid repeatedly transmitting the captured biometric data and outline image48between the BAC system and device14.

A frequently encountered problem associated with automated biometrics may be location of the biometric data offered for capture. Thus, it should be appreciated that by virtue of confirming that the outline image48is correct, the operator may also confirm that a correct location of the biometric data offered for capture has been determined.

Although hand biometric data is captured during enrollment in the BAC system12without using an outline image in the exemplary embodiment, it should be appreciated that in other embodiments a generic outline image of an average sized hand may be presented on the display screen20to facilitate capturing biometric data and generating the outline image48during enrollment. In yet other embodiments, any type of visual aid may be shown on the display screen20that would function as a guide for enabling an operator to capture the desired biometric data in accordance with a prescribed manner. Such visual aids include, but are not limited to, circles, lines, curves and marks.

Although the second stage of filtering is conducted by rotating and then filtering the gray scale hand image in the exemplary embodiment, in other embodiments instead of rotating the gray scale image, the first and second filters may be mathematically modified to effect a forty-five degree rotation prior to filtering the gray scale hand image. Applying the mathematically modified first and second filters to the gray scale hand image generates first and second rotated digital images that are about the same as those generated in the exemplary embodiment. Moreover, although the gray scale hand image is rotated by forty-five degrees in the exemplary embodiment, in other embodiments the gray scale hand image may be rotated by any angle that facilitates determining the outline image48as described herein. Furthermore, in yet other embodiments the first and second filters may be mathematically modified to effect any degree of rotation that facilitates determining the outline image48as described herein.

Although biometric data of the palm side of the right hand is used to generate the outline48in the exemplary embodiment, it should be appreciated that in other embodiments biometric data of different biometric modalities may be captured and used to generate the outline image48. Such different biometric modalities include, but are not limited to, hand geometry, face, iris, vascular patterns, hand signatures, and foot. Moreover, it should be appreciated that such different biometric modalities may have biometric features, different than wrinkles and lines that can be extracted from the captured biometric data and included in a biometric template. For example, when iris biometric data is captured during enrollment or authentication, phase information and masking information of the iris may be extracted from the captured iris biometric data and included in a biometric template.

FIG. 8illustrates capturing biometric data with the device14during authentication. Specifically, the palm side of a right hand74of an individual desiring to be authenticated is positioned proximate the device14such that an image of the hand74appears on the display screen20. It should be understood that the hand74is not controllably oriented on a surface in a fixed position or physically constrained in any way. Rather, the individual being authenticated freely positions his hand proximate to, and with respect to, the device14such that the image of the hand74appears in the display screen20. Because the hand74is not physically constrained in any way, palm biometric data may be captured while the hand74is positioned freely in space. The outline image48also appears on the display screen20during authentication in a stationary position.

FIG. 9illustrates the outline image48and an initial position of an image76of the hand74as shown on the display screen20while capturing biometric data during authentication. The hand image76in the initial position does not align with the outline image48. Consequently, the device14and the hand74are repositioned with respect to each other such that the hand image76shown on the display screen20better aligns with the outline image48shown on the display screen20.

FIG. 10illustrates the outline image48and a subsequent position of the hand image76as shown on the display screen20while capturing biometric data during authentication. After repositioning the device14and the hand74with respect to each other, the hand image76as shown on the display screen20has been rotated and translated from the initial position into the subsequent position. However, the subsequent position of the hand image76as shown on the display screen20does not adequately align with the outline image48as shown on the display screen20. Consequently, the device14and the hand74are further repositioned with respect to each other such that the hand image76as shown on the display screen20is better aligned with the outline image48shown on the display screen20.

FIG. 11illustrates the outline image48and an aligned position of the hand image76as shown on the display screen20while capturing biometric data during authentication. After further repositioning the device14and the hand74with respect to each other, the hand image76has been further rotated and translated from the subsequent position such that the hand image76as shown on the display screen20approximately aligns with the outline image48shown on the display screen20. When the hand image76shown in the display screen20approximately aligns with the outline image48shown on the display screen20, the operator captures hand biometric data by photographing the hand74with the device14.

It should be appreciated that because the hand image76aligns approximately with the outline image48during capture, hand biometric data captured during authentication is typically captured at a different, but similar, orientation as the hand biometric data captured during enrollment in the BAC system12. Moreover, it should be understood that the size of the hand biometric data image captured during authentication may typically be different than the size of the hand biometric data image captured during enrollment. In the exemplary embodiment, the size of the hand biometric data image captured during authentication is different than the size of the outline image48. Although the operator photographs the hand74with the device14in the exemplary embodiment, it should be understood that in other embodiments the security application may cause the device14to automatically photograph the hand74. In such other embodiments, a photograph may be automatically taken when the hand image76is within an established tolerance of the outline image48.

FIG. 12is a plan view of an exemplary authentication hand image78captured by the device14during authentication. The authentication hand image78includes a center point80, the hand image76, and biometric features82included in the hand image76. The biometric features82are lines and wrinkles in the exemplary embodiment. However, in other embodiments the biometric features82may be any biometric feature including, but not limited to, ridge lines.

FIG. 13is a plan view of the exemplary authentication hand image78as shown inFIG. 12, further including an authentication region of interest84. The authentication region of interest84is determined in a substantially identical way as the enrollment region of interest30. The authentication region of interest84also includes the second Cartesian coordinate system similar to the enrollment region of interest30. The authentication region of interest84defines part of biometric data captured during authentication that is to be used for authentication. Because the authentication region of interest84is positioned on the hand image76to include mostly the palm portion of the hand image76, palm biometric data is to be used for authentication in the exemplary embodiment.

In order to facilitate approximately aligning differently oriented and differently sized images of the same biometric modality, during authentication the authentication region of interest84is manipulated to be approximately the same as the enrollment region of interest30. Specifically, the size of the authentication region of interest84is increased or decreased by a scale factor such that the size of the authentication region of interest84is approximately the same as the size of the enrollment region of interest30. Furthermore, the authentication region of interest84is rotated to have approximately the same orientation as the enrollment region of interest30. It should be understood that the portion of the hand image76within the authentication region of interest84is manipulated in concert with the authentication region of interest84to have approximately the same size and orientation as the portion of the hand24within the enrollment region of interest30. By thus manipulating the authentication region of interest84and the portion of the hand image76within the authentication region of interest84, the portion of the hand image76within the authentication region of interest84and the portion of the hand24within the enrollment region of interest30may be approximately aligned with each other such that accurate authentication results may be generated. The authentication region of interest84and the enrollment region of interest30have the same shape in the exemplary embodiment. After the authentication region of interest84is manipulated to have approximately the same size and orientation as the enrollment region of interest30, a portion of the palm image76within the authentication region of interest84is converted to a gray scale image.

Although the authentication region of interest84is manipulated to have approximately the same size and orientation as the enrollment region of interest30in the exemplary embodiment, in other embodiments the enrollment region of interest30may be selected to be manipulated in a similar manner to have approximately the same size and orientation as the authentication region of interest84.

FIG. 14is a plan view of a gray scale image86converted from the hand image76within the authentication region of interest84. Because the authentication region of interest84is positioned on the hand image76to include mostly the palm portion of the hand image76, the gray scale image86is also a gray scale image of the palm and is referred to herein as a gray scale palm image86. The patch area46determined during enrollment in the BAC system12is used to facilitate determining an optimum area of the gray scale palm image86that best correlates to the patch area46. Specifically, the patch area46is incrementally positioned over the entire gray scale palm image86. In the exemplary embodiment, the patch area46is incrementally positioned over the entire gray scale palm image86one pixel row or column at a time. At each position, the patch area46is compared against the palm biometric data of the gray scale palm image86encompassed by the patch area46such that a correlation score is determined for each position. An area of the gray scale palm image86encompassed by the patch area46is referred to herein as a matching area of the gray scale palm image86. The correlation score indicates the correlation between the patch area46and a corresponding matching area of the gray scale palm image86. Comparing the patch area46against the gray scale palm image86and generating the correlation scores is referred to herein as applying the patch area46against the gray scale palm image86. It should be understood that the gray scale palm image86is rotated through a series of angles and at the same time is scaled through a series of scale factors. For each rotation angle and scale factor combination, the patch area46is applied against the gray scale palm image86.

After calculating the correlation scores for each desired rotation angle and scale factor combination, the best correlation score is determined. Optimum transformation parameters are determined to be the rotation angle and the scale factor that correspond to the best correlation score, as well as the center point coordinates of the matching area that corresponds to the best correlation score. The matching area of the gray scale palm image86that corresponds to the patch area46at the best correlation score is the optimum area of the gray scale palm image86. The gray scale palm image86is then adjusted by the rotation angle and scale factor corresponding to the best correlation score, and the coordinates of the matching area in the gray scale palm image86are calculated using the second Cartesian coordinate system. The rotation angle and the scale factor of the optimum area are also referred to as the optimum rotation angle and the optimum scale factor. The optimum rotation angle, optimum scale factor and the coordinates of the optimum area, together constitute an optimum transformation parameter set.

It should be understood that the authentication region of interest84may also be used to generate an authentication mask. Thus, by virtue of knowing the center point coordinates of the patch area46in the enrollment region of interest30, the optimum rotation angle, the optimum scale factor, and the coordinates of the optimum area center point, a transformation necessary for approximately aligning the authentication region of interest84with the enrollment region of interest30may be calculated. Likewise, the transformation may be calculated for approximately aligning the authentication mask with an enrollment mask generated during enrollment, and for approximately aligning the gray scale palm image86with an enrollment gray scale image generated during enrollment. Thus, the transformation is applied against the authentication mask to approximately align the authentication and enrollment masks. The transformation is also applied against the gray scale palm image86to approximately align the gray scale palm image86with the enrollment gray scale image.

After aligning the authentication and enrollment masks, and aligning the gray scale palm image86and the enrollment gray scale image, a biometric template is generated from the aligned gray scale palm image86. The authentication and enrollment masks are compared to determine a region common to both masks. Biometric template data generated from the aligned gray scale palm image86that is also within the common region is used to conduct a biometric authentication matching transaction. The common region may also be referred to as a region of agreement.

In the exemplary embodiment the authentication region of interest84is rotated, from its original orientation, through angles ranging from ten degrees clockwise to ten degrees counterclockwise. However, in other embodiments the authentication region of interest84may be rotated by angles greater than ten degrees in either the clockwise or counterclockwise directions. Moreover, scale factors are applied to the authentication region of interest84that increase and decrease the size of the authentication region of interest84by up to twenty percent. However, in other embodiments other scale factors may be applied that increase or decrease the size of the authentication region of interest84by greater than twenty percent.

It should be understood that the authentication mask and the gray scale palm image86each include the authentication region of interest84. Thus, all information or data included in the authentication mask and the gray scale palm image86is rotated and scaled as described above for the authentication region of interest84. Computations relating to determination of the optimum area are conducted in the second Cartesian coordinate system.

FIG. 15is a plan view of an enrollment mask88generated from the portion of the hand24within the enrollment region of interest30during enrollment. The enrollment mask88includes shaded areas90that represent areas not containing valid biometric data within the enrollment region of interest30. The mask88also includes another area92that represents areas containing valid biometric data within the enrollment region of interest30.

FIG. 16is a plan view of an authentication mask94generated from the portion of the hand image76within the authentication region of interest84during authentication. The mask94includes shaded areas96that represent areas not containing valid biometric data within the authentication region of interest84. The authentication mask94also includes another area98that represents areas containing valid biometric data within the authentication region of interest84. During authentication, the enrollment mask88and the authentication mask94are compared to define a region common to both masks88,94. Biometric data within the common region is used for matching during authentication.

FIG. 17is a flowchart100illustrating an exemplary process for enrolling individuals in the BAC system12. The enrolling process starts102by activating a security application stored in the device14. The security application causes the device14to display a message prompting the operator to capture desired biometric data. The desired biometric data is the palm side of the right hand. Next, processing continues by capturing biometric data102, in accordance with the message, from an enrollee with the device14. Specifically, in the exemplary embodiment the biometric data is captured by photographing the enrollee's hand with the device14. In the exemplary embodiment a single photograph is taken during enrollment. The device14continues processing by transmitting the captured biometric data to the BAC system12.

Next, the BAC system12continues processing by generating104the outline image48, determining106the enrollment region of interest30, and generating106the enrollment mask88. The outline image48, enrollment region of interest30, and enrollment mask88are stored in the enrollment data record of the enrollee in the BAC system12.

Processing continues by determining108the patch area46within the enrollment region of interest30, processing the patch area46into a patch area biometric template, and storing the patch area biometric template in the enrollment data record of the enrollee. After determining108the patch area46, processing continues by extracting biometric features110from the captured biometric data included in the enrollment region of interest30, and processing the extracted biometric features into an enrollment biometric template. Because the enrollment region of interest30includes mostly the palm of the hand, the extracted biometric features are palm biometric features. Thus, the enrollment biometric template includes palm biometric data. The enrollment biometric template is stored in the enrollment data record of the enrollee. After extracting the biometric features110, a message is communicated to, and displayed on, the device14notifying the user that enrollment is complete. Next, enrollment processing ends112.

Although a single photograph is taken during enrollment in the exemplary embodiment, it should be appreciated that in other embodiments a plurality of photographs may be taken that facilitates authentication as described herein. In such other embodiments each photograph is processed as described herein and is stored as an enrollment biometric template in a respective enrollment data record in the BAC system12. The enrollment regions of interest30of each enrollment photograph may be oriented to align with each other. Consequently, after aligning the respective enrollment regions of interest30, enrollment biometric templates generated for each respective photograph may also be oriented to align with each other. Next, the enrollment biometric templates are stored in the BAC system12. Moreover, in such other embodiments the outline image48is generated from a single one of the photographs. An outline image is not generated for each photograph. Furthermore, although the outline image48, enrollment region of interest30, enrollment mask88, and enrollment biometric template are stored in a respective enrollment data record for each individual enrolled in the BAC system12in the exemplary embodiment, in other embodiments additional data may be stored in the enrollment data records of each respective individual enrollee. Such additional data includes, but is not limited to, biometric templates of known imposters, and one or more lists of match scores obtained from matching transactions of known genuine or known imposter candidates. It should be understood that when such additional data is common to multiple individuals, such as biometric templates of known imposters, such additional common data may be referenced from within the enrollment data record of an individual rather than storing the same imposter data within each different enrollment data record.

Imposter biometric templates are generated through the same process used to generate enrollment biometric templates in the exemplary embodiment. The photographs used to generate the imposter biometric templates are referred to herein as imposter photographs. Thus, the enrollment regions of interest30of each imposter photograph are also oriented with each other. Moreover, the enrollment regions of interest30of each imposter photograph are also aligned with aligned enrollment regions of interest30of the enrollment photographs. Thus, the enrollment regions of interest30of all enrollment photographs and of all imposter photographs associated with an individual to be authenticated, align with each other. Consequently, imposter biometric templates generated from the imposter photographs also align with each other and with the enrollment biometric templates. In such other embodiments, when the imposter templates and the enrollment biometric templates are aligned with each other to have the same orientation, only a single authentication biometric template is required to be generated during authentication that may be compared against all of the imposter and enrollment biometric templates associated with an individual. However, in yet other embodiments, the enrollment biometric templates and imposter biometric templates may not be oriented to align with each other.

FIG. 18is a diagram114illustrating an exemplary genuine matching score distribution116and an exemplary imposter matching score distribution118. More specifically, the genuine matching score distribution116includes a plurality of genuine matching scores120and the imposter matching score distribution118includes a plurality of imposter matching scores122. The plurality of genuine matching scores120includes at least a maximum genuine matching score124and the plurality of imposter matching scores122includes at least a minimum imposter matching score126. The genuine matching score distribution116and the imposter score distribution118are separated by a distance D calculated as the difference between the minimum imposter matching score126and the maximum genuine matching score124. It should be appreciated that when the minimum imposter matching score126is greater than the maximum genuine matching score124, the minimum imposter matching score126may be considered to constitute a threshold score for use during matching transactions. Because the threshold score is determined using biometric data captured from the individual, the threshold score may be referred to as a user specific threshold score. The genuine matching scores120and the imposter matching scores122as described herein are distance scores.

It should be understood that the genuine matching score distribution116and the imposter matching score distribution118are separated by a positive distance D, such that the positions of the distributions116and118correspond to an equal error rate of zero. Consequently, because the minimum imposter matching score126is greater than the maximum genuine matching score124, any matching score value that is greater than the maximum genuine matching score124and less than the minimum imposter matching score126may be used as the user specific threshold score during authentication.

In the exemplary embodiment a maximum number of five enrollment biometric templates may be stored in the enrollment data record of each respective individual. However, in other embodiments any number of different enrollment biometric templates may be stored in each enrollment data record. When the maximum number of enrollment biometric templates is stored in an enrollment data record, and a new authentication biometric template is requested to be stored in the enrollment data record, the new authentication biometric template is compared against the five enrollment biometric templates to determine if the new authentication biometric template represents better biometric template data than any one of the five enrollment biometric templates. When the new authentication biometric template represents better biometric template data than one of the biometric templates, the one enrollment biometric template is replaced by the authentication biometric template. In the exemplary embodiment any method of determining better biometric template data may be used that facilitates generating the user specific threshold as described herein. Such methods include, but are not limited to, utilizing a quality algorithm to examine the quality and usefulness of the biometric data in the new authentication biometric template in subsequent matching transactions, and generating a quality score reflecting the determined quality and usefulness.

The information shown inFIG. 19is the same information shown inFIG. 18, as described in more detail below. As such, information illustrated inFIG. 19that is identical to information illustrated inFIG. 18, is identified using the same reference numerals used inFIG. 18.

FIG. 19is a diagram128illustrating the genuine matching score distribution116and the imposter matching score distribution118, similar to the diagram114ofFIG. 18. However, the genuine matching score distribution116and the imposter matching score distribution118share matching scores in an overlapping score distribution region130. Specifically, at least one genuine matching score120falls within the range of the imposter matching score distribution118, and at least one imposter matching score122falls within the range of the genuine matching score distribution116. The overlapping region130is the region of the genuine matching score distribution116that falls between the minimum imposter matching score126and the maximum genuine matching score124. Another portion of the genuine matching score distribution116that does not overlap with the imposter matching score distribution118constitutes a non-overlapping score distribution region132. Matching scores120that fall within the range of the genuine matching score distribution116only are considered to fall within the range of the non-overlapping score distribution region132. Matching scores120that fall within the range of the genuine matching score distribution116as well as the imposter matching score distribution118are considered to fall within the range of the overlapping score distribution region130. It should be understood that the genuine matching score distribution116and the imposter matching score distribution118may be used to calculate false match rate and false non-match rate values. These false match rate and false non-match rate values may be plotted to define a false match rate curve and a false non-match rate curve on the same diagram. It should be understood that the false match rate and false non-match rate curves may together define an overlapping error rate region that corresponds to the overlapping score distribution130. False match rate and false non-match rate values within the range of the overlapping error rate region may be deemed acceptable or unacceptable when compared against a predetermined acceptable error rate.

The information shown inFIG. 20is the same information shown inFIG. 19, as described in more detail below. As such, information illustrated inFIG. 20that is identical to information illustrated inFIG. 19, is identified using the same reference numerals used inFIG. 19.

FIG. 20is a diagram134illustrating the genuine matching score distribution116and the imposter matching score distribution118, similar to the diagram ofFIG. 19. However, the genuine matching score distribution116and the imposter matching score distribution118are positioned such that the overlapping score distribution region130is wider. As a result, it may be more difficult to identify a threshold score value in the overlapping error rate region that ensures false match rate and false non-match rate values in the overlapping error rate region are less than a predetermined acceptable error rate.

FIG. 21is a flowchart136illustrating an exemplary authentication process used by the AC system10for authenticating the identity of an individual. For AC system10, the process starts138by activating the security application140in the device14which initiates the authentication process, when the individual desires to be authenticated. It should be appreciated that the individual may desire to be authenticated in many different circumstances including, but not limited to, when conducting any kind of transaction and when requested by security personnel to prove a claim of identity. After initiating the authentication process, the device14continues processing by requesting the outline image48from the BAC system12which transmits the requested outline image48to the device14for use during authentication.

Next, processing continues by displaying a message on the display screen20prompting the operator of the device14to capture desired biometric data, and displaying142the outline image48on the display screen20in a stationary position. It should be understood that the biometric modality data captured during authentication should be the same as that captured during enrollment. Thus, biometric data corresponding to the palm side of a right hand is captured during authentication. Accordingly, the outline image48corresponds to the palm side of the right hand.

Processing continues by positioning the desired biometric data144of the individual proximate to, and with respect to, the device14such that the desired biometric data appears as a desired biometric image in an initial position on the display screen20. The operator continues processing by monitoring the desired biometric image shown on the display screen20with respect to the outline image48shown on the display screen20, and positioning the device14and the desired biometric data with respect to each other, to better align the outline and desired biometric images, when the initial position of the desired biometric image shown on the display screen20does not approximately align with the outline image48shown on the display screen20. The device14and the desired biometric data are positioned with respect to each other until the desired biometric image shown on the display screen20approximately aligns with the outline image144shown on the display screen20. After positioning the device14and the desired biometric data144such that the desired biometric image shown on the display screen20approximately aligns with the outline image48shown on the display screen20, processing continues by capturing the desired biometric data146. Specifically, the operator continues processing by photographing the desired biometric data with the device14. Thus, the desired biometric data is captured while positioned freely in space with respect to the device14. The device14continues processing by communicating the captured biometric data to the BAC system12. In the exemplary embodiment a single photograph is taken during authentication. However, in other embodiments any number of photographs may be taken.

It should be understood that desired biometric data may be captured during enrollment with the device14by approximately aligning a desired biometric data image with the outline image48on the display screen20as described herein for authentication, if an outline image48has been generated and stored in the BAC system12prior to enrollment.

Next, processing continues by generating an authentication biometric template146from the captured biometric data. Specifically, processing continues by determining the authentication region of interest84including the palm from the captured biometric data, and generating the gray scale palm image86and the authentication mask96for the captured biometric data. Processing continues by determining the optimum area within the authentication region of interest84, and adjusting the scale and angle of the authentication region of interest84such that the adjusted authentication region of interest84approximately aligns with the enrollment region of interest30. The authentication and enrollment masks, and the gray scale palm image86and enrollment gray scale image are similarly approximately aligned with each other. Next, processing continues by extracting biometric feature data from the aligned gray scale palm image86and generating an authentication biometric template146from the extracted biometric feature data. The aligned authentication and enrollment masks are compared to determine the region of agreement. Biometric feature data included in the authentication biometric template that is within the region of agreement is used for conducting biometric verification matching transactions.

Next, processing continues by conducting a plurality of 1:1 verification matching transactions146between the authentication biometric template and each of the enrollment biometric templates and known imposter biometric templates associated with the individual in the BAC system12. Matching transactions conducted between the authentication biometric template and an enrollment biometric template each generate a new genuine matching score120. Matching transactions conducted between the authentication biometric template and an imposter biometric template each generate a new imposter matching score122. The new genuine matching scores120and the new imposter matching scores122are distance scores. After generating at least one new genuine matching score120and at least one new imposter matching score122, processing continues by updating146the genuine matching score distribution116and the imposter matching score distribution118by adding the new genuine matching scores120to the genuine matching score distribution116and adding the new imposter matching scores120to the genuine matching score distribution116. Next, processing continues by calculating the maximum genuine matching score124and the minimum imposter matching score126.

Processing continues by determining148whether the minimum imposter matching score126is greater than the maximum genuine matching score124. When the minimum imposter matching score126is greater than the maximum genuine matching score124, processing continues by confirming the identity of the individual150. Upon confirming the identity of the individual150, a message is communicated to, and displayed on, the device14notifying the operator of the confirmation, and processing continues by conducting the transaction152. Next, processing ends154.

Otherwise, when the minimum imposter matching score126is not greater than the maximum genuine matching score124, processing continues by calculating an equal error rate156using the genuine116and imposter118matching score distributions. The equal error rate is the value at which the false match rate and the false non-match rate, computed using the genuine116and imposter118matching score distributions, are equal. After calculating the equal error rate156, processing continues by determining whether the calculated equal error rate is acceptable158. Specifically, processing continues by comparing the calculated equal error rate against an acceptable error rate. When the calculated error rate is less than or equal to the acceptable error rate, processing continues by confirming the identity of the individual150. Upon confirming the identity of the individual150, a message is communicated to, and displayed on, the device14notifying the operator of the confirmation, and processing continues by conducting the transaction152. Next, processing ends154.

However, when the calculated equal error rate is greater than the acceptable error rate158, the identity of the individual is not confirmed. A message is communicated to, and displayed on, the device14notifying the operator that the individual was not confirmed, and thus cannot conduct the transaction. Next, processing ends154. It should be appreciated that the power of using candidate lists and score ranks characteristic of 1:N identification is facilitated to be harnessed in a 1:1 verification scheme by virtue of confirming the identity of an individual as described in operations148,150,156, and158.

In alternative embodiments, rather than using the calculated equal error rate as part of an authentication decision as in the exemplary embodiment, the false match rate (FMR), the false non-match rate (FNMR), or combination of these may be calculated and utilized as part of the authentication decision. For example, after calculating the FMR, processing may continue by determining whether the calculated FMR is acceptable. Specifically, processing may continue by comparing the calculated FMR against an acceptable FMR. When the calculated error rate is less than or equal to the acceptable error rate, processing may continue by confirming the identity of the individual.

Although a single outline image48is generated by and stored in the BAC system12in the exemplary embodiment, in other embodiments a plurality of outline images of different biometric modalities, for each individual, may be stored in the BAC system12. In such other embodiments an outline image of the right hand and an outline image of the left hand may both be stored in the BAC system12. Thus, prior to requesting the outline image48during authentication, the operator may select one of the outline images to be used for authentication. Moreover, when the desired biometric data to be captured includes biometric data of different modalities, outline images corresponding to each different modality may be selected and presented in succession on the display screen20. For example, the left hand image outline may be displayed first and the right hand image outline may be shown on the display screen20second.

Although the genuine matching score distribution116and the imposter matching score distribution118are updated each time an individual's identity is confirmed during authentication in the exemplary embodiment, it should be appreciated that in other embodiments the genuine116and imposter118matching score distributions may be generated from only the new genuine matching scores120and the new imposter matching scores122.

Although the identity of an individual is confirmed by evaluating the maximum genuine matching score124and the minimum imposter matching score126, or by determining whether an equal error rate satisfies an acceptable error rate in the exemplary embodiment, in other embodiments the identity of an individual may be confirmed using any other method that facilitates confirming the identity of individuals. Such other methods include, but are not limited to, comparing the at least one new genuine matching score120and the at least one new imposter matching score122against a threshold score that satisfies a predetermined error rate based on the existing matching scores in the genuine matching score distribution116and the imposter matching score distribution118. In such an embodiment, the genuine matching score distribution116and the imposter matching score distribution118are not updated and the threshold score is calculated from the existing genuine matching scores120and the existing imposter matching scores122. Moreover, when a predetermined percentage of the new genuine matching scores120satisfy the threshold score the identity of the individual may be confirmed. Furthermore, the identity of an individual may be confirmed when the required percentage of new genuine matching scores120satisfies the threshold score, and a predetermined percentage of the new imposter matching scores122satisfies the threshold score. Alternatively, the identity of the individual may be confirmed when only the predetermined percentage of new imposter scores122satisfies the threshold score.

Although the genuine matching scores120and the imposter matching scores122are described as distance scores in the exemplary embodiment, it should be appreciated that in other embodiments the genuine matching scores120and imposter matching scores122may be computed as similarity scores without loss of generality. Thus, all computations described herein using distance scores also have counterpart computations based on such similarity scores.

In each embodiment, the above-described processes for capturing palm biometric data and applying a transform to the captured palm biometric data, facilitate reducing the time and costs of accurately authenticating the identity of an individual based on palm biometric data captured while positioned freely in space. More specifically, an outline image is generated from hand biometric data captured with a device during enrollment in an authentication system. During authentication, the outline image appears on the device display. While aiming the device at a hand, an image of the hand also appears on the device display. The image of the hand may be positioned within the display to be approximately aligned with the outline image. When the image of the hand approximately aligns with the outline image in the device display, the hand is captured as biometric data by the device. A region of interest defines that palm biometric data included in the captured hand biometric data is to be used during authentication. A transform is calculated and is applied to the captured palm biometric data within the region of interest. The transform causes the captured palm biometric data to have approximately the same size and orientation as the palm biometric data captured during enrollment. As a result, biometric authentication of identities facilitates reducing the time and costs associated with authentication based on palm biometric data captured while positioned freely in space with a device readily available to the members of the general public. Accordingly, biometric authentication of identities is facilitated to be enhanced in a cost effective and reliable manner.

Exemplary embodiments of processes and systems that facilitate convenient, flexible and inexpensive biometric authentication based on palm biometric data are described herein. The processes are not limited to use with the specific computer system embodiments described herein, but rather, the processes can be utilized independently and separately from other processes described herein. Moreover, the invention is not limited to the embodiments of the processes and systems described above in detail. Rather, other variations of the processes may be utilized within the spirit and scope of the claims.