Fingerprint workstation and methods

Description of equivalent WO 03063054 A2

Fingerprint Workstation and Methods

Background of the Invention

Field of the Invention

The present invention is generally related to biometric imaging systems. More particularly, the present invention is related to a fingerprint imaging system.

Related Art

Biometrics is a science involving the analysis of biological characteristics. Biometric imaging captures a measurable characteristic of a human being for identity purposes. See, e.g., Gary Roethenbaugh, Biometrics Explained, International Computer Security Association, Inc., pp. 1-34 (1998), which is incorporated herein by reference in its entirety.

One type of biometric imaging system is an Automatic Fingeφrint Identification System (AFIS). Automatic Fingeφrint Identification Systems are used for law enforcement puφoses. Law enforcement personnel collect fingeφrint images from criminal suspects when they are arrested.

One type of AFIS input device is a ten-print scanner. Typically, ten-print scanners require each finger to be imaged using a roll print. Each finger is identified prior to imaging, such as, for example, right hand thumb, right hand ring fmger, left hand middle fmger, etc. This enables the system to know whether the left or right hand is being imaged and to know where to place the imaged fingeφrint on a fingeφrint card. This process of rolling each finger to obtain fingeφrints and thumb prints during an arrest or background check is a relatively complex and time consuming process.

Also, ten-print scanners are usually custom-made consoles. Such consoles contain built-in equipment, such as a monitor, a keyboard, a pointing device, and at least one processor, for processing and viewing fingeφrint images. Custom-made consoles are very expensive, and thus, are manufactured at low volume rates. Custom-made consoles are also burdened with high maintenance costs. When the console malfunctions, the entire system is inoperable.

What is needed is a fingeφrint workstation designed for capturing plain impression fingeφrints. What is also needed is an affordable fingeφrint workstation that requires reduced complexity relative to a rolled print workstation, yet provides data and fingeφrint image integrity based on Federal Bureau of Investigation (FBI) certification standards. What is further needed is a fingeφrint workstation that captures four simultaneous fingeφrint impressions as a single image, segments the single image to create four separate images, and automatically determines whether the single image is a left or right hand image.

Summary of the Invention

The present invention solves the above-mentioned problems by providing a ten-print plain impression fingeφrint workstation that ensures data and fingeφrint image integrity as well as adheres to FBI certification standards. The present invention captures four simultaneous fingeφrint impressions as a single image and segments the single image to create four separate images. The present invention also distinguishes between the left and right hand.

Briefly stated, the present invention is directed to a ten-print plain impression fingeφrint workstation. The fingeφrint workstation comprises a ten- print scanner. The ten-print scanner has a finger guide and a platen for positioning four finger slaps onto the platen. The ten-print scanner also includes at least four indicators for providing real-time feedback for each finger of a fingeφrint image of the four finger slaps. The fingeφrint workstation also includes a computer, interfaced to the ten-print scanner via a communication link, for controlling the ten-print scanner.

Further embodiments, features, and advantages of the present invention, as well as the structure and operation of the various embodiments of the present invention, are described in detail below with reference to the accompanying drawings.

Brief Description of the Figures

The accompanying drawings, which are incoφorated herein and form part of the specification, illustrate the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art(s) to make and use the invention.

FIG. 1A is a high level block diagram illustrating a fingeφrint workstation according to one embodiment of the present invention.

FIG. IB is a diagram of an exemplary computer system.

FIG. 1 C is a block diagram illustrating an exemplary electrical system for a fingeφrint workstation according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a ten-print scanner according to one embodiment of the present invention.

FIG. 3 is a diagram illustrating a finger guide and a platen for a fingeφrint workstation according to an embodiment of the present invention.

FIG. 4A is a diagram illustrating left-hand positioning on a finger guide of a fingeφrint workstation according to an embodiment of the present invention.

FIG.4B is a diagram illustrating right-hand positioning on a finger guide of a fingeφrint workstation according to an embodiment of the present invention.

FIG. 4C is a diagram illustrating thumb positioning of a finger guide of a fingeφrint workstation according to an embodiment of the present invention.

FIG. 5 is a diagram illustrating feedback indicators for a fingeφrint workstation according to an embodiment of the present invention.

FIG. 6 is a flow diagram illustrating a method for determining the quality of individual fingeφrints according to an embodiment of the present invention.

FIG. 7 is a flow diagram illustrating a method for processing four fmger slap images. FIG. 8 is a flow diagram illustrating a method for determining whether a scanned four finger slap is a right hand or a left hand.

FIG. 9 is a block diagram illustrating an electrical/optical system of a ten- print scanner according to an embodiment of the present invention.

FIG. 10 is a diagram illustrating the placement of fingeφrints onto a fingeφrint card.

FIG. 11 is a diagram illustrating a 90 degree cross section of an exemplary optical system according to an embodiment of the present invention.

FIG. 12 is a diagram illustrating an exemplary illumination system according to an embodiment of the present invention.

The features and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings in which like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawings in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.

Detailed Description of the Preferred Embodiments

While the present invention is described herein with reference to illustrative embodiments for particular applications, it should be understood that the invention is not limited thereto. Those skilled in the art(s) with access to the teachings provided herein will recognize additional modifications, applications, and embodiments within the scope thereof and additional fields in which the present invention would be of significant utility. Overview

The present invention is a fingeφrint workstation for fingeφrint applications. The fingeφrint workstation provides simplicity when fingeφrinting applicants for submission to background checks. This is accomplished by providing four finger slap impressions in a single image. A simultaneous impression of the four fingers from one hand are captured as a single image and automatically segmented to create four separate images. After the fingeφrints from the four fingers from both hands are captured, thumb prints from both hands are captured simultaneously. Each individual extracted image is placed within the corresponding fingeφrint box on a fingeφrint card. Proper sequencing is performed using both software analysis and physical properties of a platen having a finger guide. The image size for the four finger slap images are 1600 by 1000 pixels. The segmented plain digit size is 800 by 750 pixels, and the plain thumb images are 500 by 1000 pixels. Fingeφrint images are presented on a workstation screen, such as a monitor for a personal computer, for real time quality checks and ease of correction. The fingeφrint workstation uses slap impressions, rather than traditional rolled impressions, to speed up the process of applicant processing and simplify the task of capturing quality prints.

The fingeφrint workstation provides long sustained use at an affordable cost. Affordability is achieved through many different factors. One such factor is the mechanical simplicity and reduced complexity of the workstation. The fingeφrint workstation is designed for plain impression fingeφrint capture. This alone provides a reduction in complexity relative to a rolled print design.

Another factor is the employment of an improved illumination system within the fingeφrint workstation. For example, the illumination system provides excellent uniformity performance. The illumination system is thermally stabilized and generates little or no heat, thus creating a more efficient light source. Also, the illumination light wavelength is selected to maximize fingeφrint information and definition, thereby improving the quality of a fingeφrint when dealing with overly wet or dry fingers to be fingeφrinted.

Other factors that contribute to affordability include the ability to produce the workstation in high volume, a custom set of electronics and optics, the incoφoration of a magnetic card scanner into the workstation for reduced enrollment times and less data errors, a replaceable silicone pad platen for reducing image rejections, a real-time quality control feedback system for reducing the time spent in fingeφrint acquisition, and an ergonomic case and platen design for facilitating fingeφrint capture and ease of use.

FIG. 1A is a high level block diagram illustrating a fingeφrint workstation 100 according to one embodiment of the present invention. Fingeφrint workstation 100 comprises a ten-print scanner 102, a computer 104, and an interface cable 120. Interface cable 120 is a 1394 serial interface bus for interfacing ten-print scanner 102 with computer 104. 1394 is an IEEE standard for a high performance serial bus designed to provide high speed data transfers. 1394 is a cost-effective way to share real-time information from data intensive applications, such as cameras, camcorders, VCRs, video disks, scanners, etc.

Computer 104 may be any commercial off-the-shelf computer. For example, computer 104 may be a personal computer (PC). An example implementation of computer 104 is shown in FIG. IB. Various embodiments are described in terms of this exemplary computer 104. After reading this description, it will be apparent to a person skilled in the relevant art how to implement the invention using other computer systems and/or computer architectures. Computer 104 may include one or more processors, such as processor 122. Processor 122 is connected to a communication bus 124.

Computer 104 also includes a main memory 126, preferably random access memory (RAM), and may also include a secondary memory 128. Secondary memory 128 may include, for example, a hard disk drive 130 and/or a removable storage drive 132, representing a floppy disk drive, a magnetic tape drive, an optical disk drive, etc. Removable storage drive 132 reads from and/or writes to a removable storage unit 134 in a well-known manner. Removable storage unit 134, represents a floppy disk, magnetic tape, optical disk, etc., which is read by and written to by removable storage drive 132. As will be appreciated, removable storage unit 134 includes a computer usable storage medium having stored therein computer software and/or data.

In alternative embodiments, secondary memory 128 may include other similar means for allowing computer programs or other instructions to be loaded into computer 104. Such means may include, for example, a removable storage unit 136 and an interface 138. Examples of such may include a program cartridge and cartridge interface (such as that found in video game devices), a removable memory chip (such as an EPROM, or PROM) and associated socket, and other removable storage units 136 and interfaces 138 which allow software and data to be transferred from the removable storage unit 136 to computer 104.

Computer 104 may also include a communications interface 140. Communications interface 140 allows software and data to be transferred between computer 104 and external devices. Examples of communications interface 140 may include a modem, a network interface (such as an Ethernet card), a communications port, a PCMCIA slot and card, a wireless LAN (local area network) interface, etc. Software and data transferred via communications interface 140 are in the form of signals 142 which may be electronic, electromagnetic, optical, or other signals capable of being received by communications interface 140. These signals 142 are provided to communications interface 140 via a communications path (i.e., channel) 144. This channel 144 carries signals 142 and may be implemented using wire or cable, fiber optics, a phone line, a cellular phone link, a wireless link, and other communications channels.

In this document, the term "computer program product" refers to removable storage units 134, 136, and signals 142. These computer program products are means for providing software to computer 104. The invention is directed to such computer program products. Computer programs (also called computer control logic) are stored in main memory 126, and/or secondary memory 128 and/or in computer program products. Computer programs may also be received via communications interface 140. Such computer programs, when executed, enable computer 104 to perform the features of the present invention as discussed herein. In particular, the computer programs, when executed, enable processor 122 to perform the features of the present invention. Accordingly, such computer programs represent controllers of computer 104.

In an embodiment where the invention is implemented using software, the software maybe stored in a computer program product and loaded into computer 104 using removable storage drive 132, hard drive 130 or communications interface 140. The control logic (software), when executed by processor 122, causes processor 122 to perform the functions of the invention as described herein.

In another embodiment, the invention is implemented primarily in hardware using, for example, hardware components such as application specific integrated circuits (ASICs). Implementation of hardware state machine(s) so as to perform the functions described herein will be apparent to persons skilled in the relevant art(s).

In yet another embodiment, the invention is implemented using a combination of both hardware and software.

The use of scanner 102, computer 104, and 1394 serial bus 120 versus a console configuration for an AFIS system reduces the overall system cost while providing high-speed data transfers. Current 1394 interfaces support serial transmission speeds up to 400 Mbps.

Returning to FIG. 1A, ten-print scanner 102 provides four finger slap impressions in a single image. A simultaneous impression of the four fingers from one hand are captured as a single image and automatically segmented to create four separate images. After the four fingers from both hands are captured, thumb prints from both hands are captured simultaneously. Each individual extracted image is placed within the corresponding fingeφrint box on a fingeφrint card. Proper sequencing is performed using both software analysis and physical properties of a platen having a fmger guide. Fingeφrint images are presented on a monitor associated with computer 104 for real time quality checks and ease of correction.

Ten-print scanner 102 comprises an electrical system 102 A and an optical system 102B. The combination of electrical system 102A and optical system 102B provides electro-optical technology for capturing plain impression fingeφrints. Electrical system 102 A provides power to ten-print scanner 102, controls status signals for various components internal to ten-print scanner 102, controls all input/output signals between components internal to ten-print scanner 102, and controls input/output signals between ten-print scanner 102 and computer 104 via IEEE 1394 interface cards 108 and 106, respectively. Optical system 102B enables scanner 102 to illuminate an area of a platen for receiving a finger or fingers, measure the reflected light optically, and convert the resulting signals into a fingeφrint image.

The Electrical System

FIG. IC is a diagram illustrating one embodiment of electrical system 102 A. Electrical system 102 A comprises an interface board 150, two digital camera boards 152, an illuminator/prism heater board 154, an indicator board 156, and a magnetic-stripe reader 158. Interface board 150 is coupled to digital camera boards 152, illuminator/prism heater board 154, indicator board 156, and magnetic-stripe reader 158. Interface board 150 also interfaces each of boards 152, 154, and 156, and magnetic-stripe reader 158 to computer 104.

Interface board 150 comprises a controller 160, a digital camera interface 162, a magnetic-stripe reader RS-232 serial interface 164, a 2D barcode RS-232 serial interface 166, EEEE-1394 interface 108, and a power supply interface 168. Controller 160 is coupled to digital camera interface 162, illuminator/prism heater board 154, indicator board 156, magnetic-stripe reader RS-232 serial interface 164, 2D barcode RS-232 serial interface 166, and IEEE-1394 interface 108.

Controller 160 and IEEE-1394 interface 108 provide a communication link between ten-print scanner 102 and computer 104. In embodiments, controller 160 may be any one of a microprocessor, a microcomputer, a microcontroller, etc. In one embodiment, controller 160 maybe used to control digital cameras mounted on digital camera boards 152, a light source 170 used in optical system 102B, a prism heater 172 used to remove unwanted moisture from a platen, indicators used to indicate power status, card swipe status, and quality of fingeφrint status, magnetic-swipe reader 158, and an external 2D barcode reader 174 that may be attached to scanner 102 via 2D barcode RS-232 serial interface 166. In another embodiment, both controller 160 and computer 104 are used to control the digital cameras, light source 170, prism heater 172, power/card swipe/fingeφrint quality indicators, magnetic-swipe reader 158, and external 2D barcode reader 174. In yet another embodiment, computer 104 is used to control the digital cameras, light source 170, prism heater 172, power/card swipe/fmgeφrint quality indicators, magnetic-swipe reader 158, and external 2D barcode reader 174, and controller 160 is used as a conduit.

2D barcode reader 174 and magnetic-stripe reader 158 may be any off the shelf serial devices used to scan bar codes and data from documents, respectively. Bar codes and documents may include, but are not limited to, identification information, account information, fingeφrint code information, etc. 2D barcode reader 174 is coupled to controller 160 via 2D barcode RS-232 serial interface 166. Magnetic-stripe reader 158 is coupled to controller 160 via magnetic-stripe RS-232 serial interface 164.

The use of 2D barcode reader 174 and magnetic-stripe reader 158 reduce enrollment times and result in less data errors. For example, 2D barcode 174 and/or magnetic-stripe reader 158 may be used in conjunction with a user interface to simplify demographic data entry. Demographic information swiped from magnetic-stripe reader 158 or 2D barcode reader 174 may be sent to controller 160 via interfaces 164 and 166, respectively, and controller 160 will transmit the information to computer 104 via IEEE-1394 interface 108.

Although not specifically shown in FIG. IC, power supply interface 168 supplies power to all of the components within ten-print scanner 102 and interfaces to an external 12-volt power supply 180.

Digital camera interface 162 couples to controller 160 via a serial connection. Digital camera interface 162 is also connected to digital camera boards 152 to provide electronics for clocking data to and from digital cameras mounted onto digital camera boards 152. Controller 160 may send control signals to each camera serially via digital camera interface 162. Digital camera interface 162 is also connected to IEEE-1394 interface 108 for sending 16-bit image data from the cameras mounted on digital camera boards 152 to computer 104.

Illuminator/prism heater board 154 is coupled to controller 160 via a serial interface. Controller 160 controls different zones of light source 170 in the illumination system of optical system 102B. The light source is an illumination source array. The illumination source array is divided into zones. In one embodiment, a plurality of sources are divided into at least three groups in at least three respective zones. The intensity of each group of sources is independently controlled by controller 160 relative to other groups such that a flat, uniform illumination is provided to the platen. Use of such zones simplifies control while still retaining sufficient flexibility to adjust the relative intensity of the light source groups to ensure flat, uniform illumination is provided to the platen. A more detailed description of the illumination source array and its division into zones is found in "Systems and Methods For Illuminating A Platen In A Print Scanner," U.S. Provisional Patent Application Serial No. TBD (Attorney Docket No. 1823.0570000), by Arnold et al, which is incoφorated herein by reference in its entirety.

Water vapor that condenses onto a fingeφrint platen surface of a prism may cause an undesirable fingeφrint image called a halo. To prevent this from occurring, the fingeφrint platen of scanner 102 is heated to remove water vapor that condenses onto the platen surface of the prism or to prevent such water vapor from forming. A system and method for heating the platen using heating elements attached to the sides of a prism is described in "Platen Heaters For Biometric Image Capture Devices," U.S. Provisional Patent Application Serial No. TBD (Attorney Docket No. 1823.0550000), by Carver et al, filed concurrently herewith and incoφorated by reference herein in its entirety. In one embodiment, controller 160 controls trip point limits for turning heating elements on and off when heating the fingeφrint platen. Controller 160 also monitors the temperature of the fingeφrint platen via a thermostat controller. In one embodiment, this information maybe transmitted to computer 104 via IEEE 1394 interface 108.

Ten-print scanner 102 provides real-time feedback of fingeφrint quality. This is accomplished using fingeφrint quality indicators. Fingeφrint quality indicators (shown in FIG. 2) provide feedback to the user to indicate whether an appropriate level of fingeφrint quality has been achieved. Fingeφrint quality indicators include four indicators, one for each fmger of the four fmger slap being scanned. Fingeφrint quality indicators and the process used for determining the quality of each fingeφrint is discussed in more detail below.

Indicator board 156 is coupled to controller 160 via a serial input/output connection. Controller 160 provides control signals to indicator board 156 for illuminating indicators, such as LEDs (light emitting diodes) to indicate whether the quality of a particular fingeφrint for a particular fmger is good or bad. Controller 160 also provides a control signal for indicating that the system is powered-ON and control signals indicating whether a card swipe from magnetic- stripe reader 158 or 2D barcode reader 174 is successful. For example, if a card swipe is not successful, a CARD LED located on scanner 102 will be illuminated RED indicating that the card must be swiped again. Alternatively, if the card swipe is successful, the CARD LED will be illuminated GREEN. The Optical System

FIG. 9 is a block diagram illustrating scanner optical system 102B often print scanner 102. Scanner optical system 102B comprises an illumination system 902, a prism 904, optical systems 906 and 908, and two cameras 910 and 912. As previously stated, one side of prism 904 is used as platen 204 and includes fmger guide 206. Illumination system 902 illuminates the underside of platen 204. Finger guide 206 is separated into left side 304 and right side 306. In one embodiment, camera 910, in combination with optical system 906, is used to detect an image of the fingers placed on the left side 304 of fmger guide 206 and camera 912, in combination with optical system 908, is used to detect an image of the fingers placed on the right side 306 of finger guide 206. Digital cameras 910 and 912 can be any solid state digital camera, such as a CCD or CMOS camera. In one example, digital cameras 910 and 912 may be provided on digital camera boards 152 described in FIG. IC.

A 90 degree cross section of an exemplary optical system, such as, for example, optical system 906 or 908, is shown in FIG. 11. Optical system 1100 shows prism 904, an optical housing 1102, and camera 910 or 912. Optical housing 1102 is coupled to prism 904 at one end and to camera 910 or 912 using a focus mount 1116 at the opposite end. Optical housing 1102 includes, inter alia, a first lens element 1104, a fold mirror 1106, a second lens element 1108, a third lens element 1110, a fourth lens element 1112, and an aperture stop 1114.

A biometric object, such as a finger or fingers, placed on prism 904 for imaging, is focused through first lens element 1104 and reflected off of fold mirror 1106. Aperture stop 1114 is used to limit light passing through optical system 906 or 908 such that only light rays traveling within a range of angles at or near a direction along an optical axis are detected. The reflected image is then focused through second, third, and fourth lens elements 1108, 1110, and 1112 for detection by camera 910 or 912. First and second lens elements 1104 and 1108 are comprised of convex disks made of SF3 glass and LaKlO glass, respectively. Third lens element 1110 is comprised of concave disks made of SF8 glass and fourth lens element 1112 is comprised of concave and convex disks made of SKI 6 glass. Although lens elements 1104, 1108, 1110, and 1112 are comprised of glass, they are not limited to glass. In fact, lens 1104, 1108, 1110, and 1112 can be made of any transparent material that can focus light rays and form images by refraction.

An exemplary illumination system, such as illumination system 902, is shown in FIG. 12. In one embodiment, illumination system 902 includes an illumination source array 1202, a light wedge 1204, and a diffuser 1206. Illumination source array 1202 illuminates an end region of light wedge 1204. Light wedge 1204 then internally reflects light and sends it to diffuser 1206 prior to entering prism 904. The light from illumination source array 1202 can be any single wavelength or narrowband of wavelengths such as infra-red, visible or ultraviolet light. In one example, blue/green light having a wavelength of approximately 510 nm is used. Illumination system 902 is further described in "Systems and Methods For Illuminating A Platen In A Print Scanner," U.S. Provisional Patent Application Serial No. TBD (Attorney Docket No. 1823.0570000), by Arnold et al, and is incoφorated herein by reference in its entirety.

Finger Guide and Platen

FIG. 2 is a diagram illustrating an embodiment often-print scanner 102. A housing 202 for ten-print scanner 102 is constructed of impact resistant injection molded polycarbonate. One skilled in the relevant art(s) would know that other types of housings could be used without departing from the scope of the invention. Ten-print scanner 102 shows a fingeφrint platen 204, a fmger guide 206, fingeφrint quality indicators 208, a power indicator 210, and a card indicator 212. Ten-print scanner 102 also shows magnetic-stripe reader 158 located at the top of ten-print scanner 102. Fingeφrint quality indicators 208 are located directly above finger guide 206. Power indicator 210 is illuminated when power is applied to scanner 102 via external 12-volt power supply 180. Card indicator 212 is illuminated green when a card swipe is successful and red when a card swipe is unsuccessful.

Fingeφrint platen 204 is a receiving surface for placement of the four finger slaps and the thumbs during fingeφrinting. In one embodiment, platen 204 is one side of a prism (not shown). In another embodiment, platen 204 is one side of a prism with an optical quality silicone rubber sheet placed on top. The optical quality silicone rubber sheet is replaceable. Optical quality silicone rubber platens provide adequate surface quality to optimize image enhancements as well as protect the optical surface. Optical quality silicone rubber platens are further described in U.S. Provisional Patent Application No. 60/292,341, "Silicone Rubber Surfaces for Biometric Print ΗR Prisms," filed May 22, 2001 , and U.S. Provisional Patent Application No. 60/286,373, "Silicone Rubber Surfaces for Biometric Print TIR Prisms," filed April 26, 2001 , both of which are incoφorated by reference herein in their entireties.

Finger guide 206 is located along the sides and the top of fmgeφrint platen 204. Finger guide 206 is a mechanism for locating and separating the four finger slap to provide accurate and efficient placement of fingers. Finger guide 206 also provides a physical barrier that facilitates the identification of either a right or left hand using post software analysis of the four finger slap fingeφrint images.

FIG.3 is a diagram illustrating finger guide 206 and fingeφrint platen 204 for fingeφrint workstation 100 according to an embodiment of the present invention. As previously stated, one side of a prism is used as fingeφrint platen 204. Fingeφrint platen 204 includes an optical quality silicone rubber sheet attached to the side of the prism used as the platen. The optical silicone pad may be easily removed and replaced by operating personnel when needed. The size of the active fingeφrint platen area 204 is 2.05 by 3.6 inches at 500 dpi. Finger guide 206 includes a physical barrier 302 positioned along the middle of the top of finger guide 206. Physical barrier 302 is used to separate the four finger slap. Two fingers of the four finger slap are placed on a left side 304 of physical barrier 302 while the other two fingers of the four finger slap are placed on a right side 306 of physical barrier 302.

FIG. 4A is a diagram illustrating four finger placement of a left hand on fingeφrint platen 204 and finger guide 206. As is shown in FIG. 4A, when the left hand is placed onto platen 204, finger guide 206 physically separates the ring fmger and the middle finger of the left hand. Finger guide 206 is designed so that when the tips of the middle and ring fingers make contact with finger guide 206, the four fingers are positioned coπectly in the viewing area. This forces the four fingers to have a diagonal orientation. This is also true for a right hand positioned onto fingeφrint platen 204, as shown in FIG. 4B. Based on the orientation of the four fingers on the viewing area and the separation of the ring and middle fingers on fmger guide 206, a determination can be made as to whether the left or right hand is placed onto fingeφrint platen 204. The process for determining whether a left or right hand is being imaged is described below with reference to FIGs. 6, 7, and 8. FIG. 4C is a diagram illustrating the placement of the thumbs onto fingeφrint platen 204. When thumb prints are captured, the left thumb is placed on left side 304 of finger guide 206 and the right thumb is placed on right side 306 of finger guide 206.

Real-Time Feedback Quality Indicators

The present invention provides feedback of real-time individual fingeφrint quality to the user. Providing real-time fingeφrint quality feedback simplifies the use of fingeφrint workstation 100 and facilitates capturing of the best possible fingeφrints.

FIG. 5 is a diagram illustrating feedback indicators 208 for fingeφrint workstation 100. An indicator (502, 504, 506, and 508) is assigned to each fmger of the four finger slap being scanned. For example, if a left hand is placed on fingeφrint platen 204, indicator 502 conesponds to pinky finger 510, indicator 504 conesponds to ring finger 512, indicator 506 conesponds to middle finger 514, and indicator 508 conesponds to pointer fmger 516. If a right hand is placed on fingeφrint platen 204, indicator 502 conesponds to pointer finger 516, indicator 504 conesponds to middle finger 514, indicator 506 conesponds to ring fmger 512, and indicator 508 conesponds to pinky finger 510.

Each image frame is processed to determine the quality of the individual fingeφrint. After determining the quality of each individual finger, the conesponding indicators 502, 504, 506, and 508 provide feedback to the user for possible coπections or re-positioning of fingers 510, 512, 514, and 516 on fingeφrint platen 204 so that an appropriate level of fingeφrint quality can be achieved. For example, one embodiment may use multi-color LEDs for indicators 502, 504, 506, and 508. In such an embodiment, a red LED may indicate poor quality, a green LED may indicate acceptable quality, and an amber LED may indicate indeterminate quality. In another embodiment, indicators 502, 504, 506, and 508 may be bar graph LED indicators, wherein the level of the bar indicates quality acceptance.

FIG. 6 is a flow diagram 600 illustrating a method for determining the quality of individual fingeφrints according to an embodiment of the present invention. The invention is not limited to the description provided herein with respect to flow diagram 600. Rather, it will be apparent to persons skilled in the relevant art(s) after reading the teachings provided herein that other functional flow diagrams are within the scope of the present invention. The process begins with step 602, where the process immediately proceeds to step 604.

In step 604, a four finger slap image is scanned. The scanned image is then processed in step 606. The procedure for processing the image is further described with respect to FIG. 7.

In step 608, each finger of the four finger slap image is separated into its own image. The process then proceeds to step 610. In decision step 610, it is determined whether the processed image is the first image scanned. If it is the first image scanned, the process proceeds back to step 604 to scan another image.

Returning back to decision step 610, if it is detennined that the processed image is not the first image, the process proceeds to step 612.

In step 612, each individual fmgeφrint is compared to a conesponding previous fingeφrint. According to the results of the comparison, each fingeφrint is classified in step 614. If the area and shape of the cunent fingeφrints are of equal size and shape or within some threshold for good quality of the previous fingeφrints, then the indicator light is illuminated green, indicating that the fingeφrint is of good quality for that finger. If the area and shape of the cunent fingeφrints are below the threshold for good quality, but above a threshold for bad quality, then the indicator light is illuminated amber, indicating that the fingeφrint is indeterminate for that fmger. If the area and shape of the cunent fingeφrint is at or below the threshold for bad quality, then the indicator light is illuminated red, indicating that the fingeφrint is of bad quality. Threshold levels are changeable and may be based on customer requirements. For example, one customer's requirements may be to set the good quality threshold at 90% and the bad quality threshold at 10%. Another customer's requirements may not be as stringent, only requiring the good quality threshold to be at 80% and the bad quality threshold to be at 20%.

In step 616, each indicator is illuminated according to the classification of the fingeφrint. The process then proceeds to decision step 618.

In decision step 618, it is determined whether all fingeφrints for the four finger slap are of good quality. If the fingeφrints for each finger of the four finger slap are of good quality, the process proceeds to step 620, where a determination is made as to whether a left or right hand is being imaged. This process is described with reference to FIG. 8.

Returning to decision step 618, if the fingeφrints for each finger of the four fmger slap are not of good quality, the process then returns to step 604 to scan another image. This process will repeat itself until either fingeφrints of good quality for all fingers are achieved or a time-out has occuπed. If a time-out occurs, a message is displayed to the operator indicating that the operator may switch from an automatic detection mode to a manual mode and repeat the process manually, if necessary. Alternatively, the operator may use a modified version of the program for special circumstances. Such circumstances may include, but are not limited to, a person having less than four fingers for a four finger slap.

Once good quality fingeφrints are achieved for both four finger slaps and thumbs, four finger slap prints 1002, thumb prints 1004, and segmented fingeφrints 1006 are placed on a fingeφrint card 1000, as illustrated in FIG. 10 for a right-hand.

FIG. 7 is a flow diagram illustrating method 606 for processing the four fmger slap image. The invention is not limited to the description provided herein with respect to flow diagram 606. Rather, it will be apparent to persons skilled in the relevant art(s) after reading the teachings provided herein that other functional flow diagrams are within the scope of the present invention. The process begins with step 702, where the process immediately proceeds to step 704.

In step 704, the scanned image is filtered to remove all high frequency content from the image. A fingeφrint is comprised of ridges and valleys. The high frequency content of a fingeφrint consists of ridge and valley transitions. The image is filtered to remove all of the ridge and valley transitions. This results in an image where the ridges and valleys of the fmger are combined to indicate the outlying of the fingeφrint area. The process then proceeds to step 706.

In step 706, a binarization process is performed. The binarization process removes all of the gray areas and replaces them with either black or white pixels based on a black and white threshold point. In one embodiment, the process begins by taking the average gray scale value of the filtered image. This average gray scale value is refened to as the black and white threshold point. All of the pixel values above the average value are replaced with white pixels and all the pixels values equal to and below the average value are replaced with black pixels. The resulting image is comprised of all black and white pixels. The process then proceeds to step 708.

In step 708, the fingeφrint area is detected. Usually, the black areas of the image are concentrated around the fingeφrints. The detection step detects the areas concentrated by black pixels. The process then proceeds to step 710.

In step 710, the fingeφrint shapes are detected. The fingeφrint shapes are oval-like shapes. This detection step detects the areas concentrated by black pixels that are comprised of oval-like shapes. The process then proceeds to step 712.

In step 712, it is determined whether the detected areas and shapes are representative of a four finger slap. If it is determined that the detected areas and shapes are not representative of the four finger slap, then the process returns to step 604 in FIG. 6 to scan another image. If it is determined that the detected areas and shapes are representative of the four finger slap, then the process proceeds to step 608 in FIG. 6 to separate the image into individual fingers.

Returning to FIG. 5, in yet another embodiment of the present invention, indicators 502, 504, 506, and 508 may be used to indicate whether or not fingeφrints are being imaged. For example, if indicators 502, 504, 506, and 508 are green, then fingeφrints are being imaged. If indicators 502, 504, 506, and 508 are red, then fingeφrints are not being imaged.

FIG. 8 is a flow diagram 620 illustrating a method for determining whether a scanned four finger slap is a right hand or a left hand. The invention is not limited to the description provided herein with respect to flow diagram 620. Rather, it will be apparent to persons skilled in the relevant art(s) after reading the teachings provided herein that other functional flow diagrams are within the scope of the present invention. The process begins with step 802, where the process immediately proceeds to step 804. As previously stated, the orientation of the four fingers on the viewing area or fingeφrint platen 204 and the separation of the ring and middle fingers by physical barrier 302 of finger guide 206 are used to determine whether the left or right hand is placed onto fingeφrint platen 204 for imaging. For optimal performance, one must place their fingers onto fingeφrint platen 204 in a manner such that the largest area possible of the fingeφrint image is obtained, while capturing all four fingers. In order for this to occur, one must place a four finger slap at a diagonal with the tips of the middle finger and the ring finger making contact with finger guide 206. Other positions may also be possible.

In decision step 804, it is determined whether the detected fingeφrints are at a diagonal. If the image is at a diagonal, it is then determined whether the diagonal is less than 90 degrees or greater than 90 degrees (step 806). If the diagonal is less than 90 degrees, then the left hand is being imaged (step 810). If the diagonal is more than 90 degrees, then the right hand is being imaged (step 808).

Although placing one's fingers at a diagonal may be an optimal position, the invention is not limited to diagonal positioning of the four finger slap. Other positions may be possible.

Returning to decision step 804, if it is determined that the fingeφrints are not at a diagonal, then the process proceeds to decision step 812.

In decision step 812, it is determined whether the longest finger (i.e., the middle fmger) is on right side 306 of physical barrier 302. If the longest finger is on right side 306 of physical barrier 302, then the left-hand is being imaged (step 816). If the longest finger is not on right side 306 of physical banier 302, then the right-hand is being imaged (step 814).

In an alternative embodiment, decision step 812 may be altered to determine whether the pinky finger (t.e., the smallest finger) is on right side 306 of physical banier 302. If the pinky finger is on right side 306 of physical barrier 302, then the right-hand is being imaged. If the pinky finger is not on right side 306 of physical barrier 302, then the left-hand is being imaged. Alternatively, decision step 812 may search left side 304 of physical barrier 302 to determine whether the longest finger or the shortest finger can be found.

Conclusion

While specific embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.