RU2474876C2 - System and high-efficiency multimode scanning device for obtaining palmprints and fingerprints - Google Patents

Abstract

FIELD: information technology.

SUBSTANCE: system for optical imaging an object in the field of view comprises an optical plate having a surface which receives the object; a light source for illuminating the surface which receives the object; an imaging system having an image plane and meant for receiving light from the surface which receives the object in order to form an image of the object on the surface which receives the object; and a lens mechanism for focusing light from the surface which receives the object onto the image plane, wherein the system is focused for recording the image in the full field of view and for recording the region of interest in the field of view, and the lens mechanism is a six-component lens; the imaging system is configured to provide a higher frame frequency in the region of interest when the region of interest is smaller than the field of view.

EFFECT: smaller size of the device, recording rolled fingerprints, applied fingerprints and palmprints in one continuous workflow in a compact device, differentiation of moisture, clearer image, enabling use of one scanning device to record palmprints and fingerprints measuring 500 or 1000 pixels per inch.

18 cl, 11 dwg

Description

CROSS REFERENCE TO RELEVANT APPLICATIONS

This application claims benefit in accordance with Clause 35 of US Code 119 (e) for provisional application US No. 60/967601, filed September 4, 2007, entitled "SYSTEM AND MULTIMODE SCANNING DEVICE FOR RECEIVING A HIGH-QUALITY HAND PRINT AND PRINTING PRINTING". Included as a reference.

PREVIOUS TECHNOLOGY

Fingerprint imaging systems use the well-known contact method for creating a fingerprint pattern, in which the surface relief of the finger is approximated by a series of combs with intermediate depressions. Conventional devices for recording the full image of the hand (brush), which record the full image of fingerprints and palms, require moving the hand along a cylindrical drum or plate in order to record the formation data of the scallops of the hand and palm. This requires significant operator skill. Moreover, the technical system for recording such images uses a linear structure sensor that is not suitable for recording rolled fingerprints. There are palm recorders that use a fixed flat prism in combination with a moving linear structure mechanism. This system requires less operator skill, but only records the palm image.

There are other hand / palm image recording systems that utilize a hand-receiving conical shape in combination with a movable optical / imaging system to form a hand / palm image. However, this system is not ergonomically and electronically adapted to scan rolled fingerprints. In addition, a physically very large large-sized room is required to accommodate the desired mechanism, and significant operating power is required to move the mechanism under control and heat up the conical shape receiving the hand in order to avoid condensation due to wet hands.

Systems were used using two scanning devices: one for recording a palm and a fingerprint (slap) of a finger, and the other for recording a rolled fingerprint; however, they are physically large and heavy and due to the two scanners are expensive to manufacture. Moreover, these devices require significant power for operation, partly because of the need to heat large prisms to avoid condensation due to wet hands.

Systems using a lighting scheme with optical fibers were applied. However, the illuminated surface is relatively small, and the structure of the fiber is designed with a small number of LED light sources located on the side of the fiber. In order to receive light from light emitting diodes (LEDs), this system requires a large thickness of the light guide, which limits the ergonomic design of the device housing to adapt the position of the finger under the prism illumination surface.

SUMMARY OF THE INVENTION

In one aspect, the invention shows systems, devices, and methods for enabling the recording of a rolled fingerprint and palm recording in a device having a reduced size. In some embodiments, systems and methods include recording rolled fingerprints, attached fingerprints, and palm prints in one continuous workflow in a compact device. In some embodiments, humidity-sensing and / or enhanced-definition optical elements are provided, originally achieved only in devices designed to record only fingerprints. In some embodiments of the system, a single scanning device is used to record palm or fingerprint images at 550 pixels per inch and / or 1000 pixels per inch.

In one aspect, the invention provides a system for optical imaging of an object. The system includes an optical plate having a surface receiving an object large enough to display a palm. A light source is located to illuminate the surface receiving the object. An image forming system having an image plane is mounted to receive light from a surface receiving an object in order to form an image of an object on a surface receiving an object. The lens mechanism is designed to focus light from the surface receiving the object onto the image plane. In various embodiments, the system provides an optical system that provides a high frequency contrast characteristic (MTF) across the entire field of view, sufficient to record a palm image satisfying the FBI Appendix F, plus a high MTF in the lower field of view for display satisfying the FBI application , images of a rolled finger. In some embodiments, the lower region includes the right and left corners of the surface receiving the object.

Various embodiments of the invention may include one or more of the following features. The imager provides the addressability of the region of interest, suitable for determining the area of the rolled finger in an ergonomically acceptable region of the field of view (FOV), and provides a frame rate in this region above 12 frames per second. In accordance with various embodiments, the lens mechanism includes a plurality of lens elements, in one embodiment, two pairs of doublets and two singlets. The lens mechanism eliminates a significant portion of chromatic aberration. The lens mechanism includes an aperture. The system may further include one or more folding mirrors to direct light from the surface receiving the object into the lens mechanism. The system in certain embodiments comprises three folding mirrors. The system may include a monochromatic CMOS imager. The imaging device is rotated at an angle from the normal. In other embodiments, the implementation of the system includes either CERs or CMOS imager. The system provides images with 500 and 1000 pixels per inch. The system is configured to record images of at least four pressed fingers, a single pressed finger, and rolled fingerprints. Also, in some embodiments, the optical system does not require geometric distortion correction in the software and does not display moisture.

In another aspect of the invention, a lighting circuit is provided that provides uniform illumination over the entire field of view and is mechanically thin to allow optimal ergonomic cutout sufficient to move the finger and thumb when rolling fingerprints.

Details of one or more embodiments are indicated below in the accompanying drawings and are described below. Other characteristics, objects, and advantages will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

1 shows a schematic cross-sectional side view of an image system in accordance with some embodiments of the present invention.

2 schematically illustrates a top view of a lighting source in accordance with some embodiments of the present invention.

Figure 3 schematically illustrates an oblique projection of the lighting source described in Figure 2

Figure 4 schematically illustrates a side view of the lighting source described in Figure 2.

5 schematically illustrates the arrangement of various components of a light source in accordance with some embodiments of the present invention.

6 schematically illustrates elements of a lens system of a lens in accordance with some embodiments of the present invention.

7 illustrates an opto-mechanical implementation of a system in accordance with some embodiments of the present invention.

8A and 8B show modulation transfer function (MTF) profiles over the entire field of view of an image system in accordance with some embodiments of the present invention.

FIG. 9 shows possible areas of overlapping profile of a modulation transfer function (MTF) field of view of an image system in accordance with some embodiments of the present invention.

Figure 10 schematically illustrates a processing system for the image system of Figure 1.

DETAILED DESCRIPTION

As an identifier that cannot be lost or forgotten, the systems and devices for obtaining a fingerprint and a fingerprint described herein have a wide range of applications that are constantly expanding. For example, fingerprints and fingerprints can be used as access keys.

A fingerprint and palmprint image device can be used to record images of four pressed fingers, a single pressed finger and rolled fingerprint images, as well as to record palm and whole hand images. In some embodiments, the implementation of such a device generates images of 1000 pixels per inch (ppi), as well as images of 500 ppi. Images meet or exceed specific requirements or standards, for example, the requirements of Appendix F of the FBI Electronic Fingerprint Transmission Specification (CJIS-RS-0010) at all frequencies of test signals up to the frequency and including the frequency at which the sample causes interference. The fingerprint and palm imaging device also supports higher resolution images and is compatible with evolving standards.

Figure 1 shows a system 10 for obtaining a fingerprint and palm. While previous fingerprint and palm systems used a dual-camera system to display (1) palm / fingerprints and (2) rolled fingerprints, system 10 allows the use of a single low frame rate addressable region of interest (ROI) imager ) together with optical elements with a large field of view (FOV) and a structurally thin prismatic light source to record palm prints, fingerprints and rolled fingerprints fingers in one low-cost physically compact device. This system provides the ability to achieve high-quality imaging over the entire required field of view with particular attention to the lower area of the field of view, where rolled fingerprints must be recorded due to ergonomic limitations and where performance is usually impaired due to conventional optical element designs. In accordance with various embodiments, the system introduces functionally desirable features, for example, optical elements that distinguish humidity, and high-contrast enhanced definition through over sampling and optics with a very small blur spot.

As shown in FIG. 1, system 10 includes an optical plate or plate 32, primary lenses 24, mirror system 36, lens lens system 22, image sensor system 38, and light source 18. For information, the Y and Z axes of the orthogonal coordinate system are shown in FIG. 1 arrows. The third X axis of this orthogonal coordinate system is perpendicular to the plane of the drawing in FIG. 1. The surface 12 receiving the object includes the plane of the system object and is one surface of the prism 15. An object, such as a palm or one or more fingers to be identified, is applied to the surface 12. The other surface 14 of the prism is configured to receive a light source for surface 12 of the plane of the object. The surface 12 of the plane of the object may include areas of the finger field for interaction with scallops and grooves of the skin of the finger and palm areas for interaction with scallops and grooves of the skin of the palm. The surface 12 receiving the object has an optically soft surface to provide good contact with the combs of the skin. In accordance with various embodiments, the surface receiving the object is large enough to provide sufficient X-Y dimensions for the palm image as well as the image of the rolled finger. In some embodiments, the surface receiving the object is large enough to provide a satisfactory size for the image of the palm, as well as up to four fingerprints at the same time, as well as for the image of a rolled finger. A surface receiving an object in the X-Y plane, for example, can be about 127 millimeters (mm) in length (X-axis) and about 127 mm in width (Y-axis). The third face 16 of the prism is a viewing face through which the plane of the illuminated object is viewed due to total internal reflection (TIR). When a palm or finger is applied to the plane 12 of the object, the rubbing element of the palm or finger is visible due to the impaired total internal reflection (FTIR). The surface 12 receiving the object and the surfaces 14 and 16 are flat in shape. Other shapes are possible for both one and both of these surfaces, such as, for example, cylindrical shapes to enhance various image characteristics. The surface 14 is configured to receive a light source for the surface 12 of the plane of the object. Surface 16 is also a viewing face through which the plane of the illuminated object is viewed with TIR. The surface 14 is inclined at an angle to the surface receiving the object, as shown in FIG. The magnitude of this angle is generally chosen so as to perform the desired illumination of the plane of the object. The surface 16 is inclined to the surface receiving the object. The surface 12 of the plane of the object is illuminated through the illuminating face 14 of the prism at an angle approximately equal to the viewing angle (25-50 °). The angles between the surface 12 of the plane of the object and the surface 16 and between the surface 12 and the surface 14 can be, in one embodiment, approximately 40 ° and 50 °, respectively. This embodiment represents bright field illumination. Dark field illumination can also be used, in which the plane of the object is illuminated at an angle of approximately 90 °. In this case, the rubbing scallops of the finger are visible as a bright object on a dark background field. The implementation of a dark field may be preferable in some cases, when the layout of the optical elements dictates that the illumination comes from a prism of the plane of the object or plate other than the front surface.

The primary lens 24 is located outside the optical plate 32 and beyond its lateral surface 16. The primary lens 24 may include, for example, a square field lens. The field lens performs telecentricity of the rays on the plane of the object. The lens directs light from the plane of the object into the lens system 22 of the lens. In a specific embodiment, the field lens is a biconvex lens with the following characteristics: radius: 513,500 mm ed., 513,500 mm ed .; edge diameter: 96.0x144.0; thickness: 18,000 mm; Material: F2.

When the finger and / or palm is applied to the plane of the object, the element of the finger comb is visible due to impaired total internal reflection (FTIR). An optical plate or prism in one embodiment applies the principle of moisture discrimination, according to which the refractive index of glass and the viewing angle of the plane of the object can distinguish the refractive index of the skin from the refractive index of both air and water on the surface of the plane of the object. This technique is disclosed in US Patent No. 5,416,573, entitled “Device for Obtaining Fingerprint Images That Are Significantly Free from Interference Due to Moisture on the Finger to Be Imprinted”, assigned to the assignee of this application, and which is incorporated herein by reference.

Specifically, in one embodiment, the image sensor system 38 receives light from the surface of the plate on which air or water is in contact with this surface, but receives significantly less light from areas of the surface of the plate where the skin of the rubbing comb is in contact. In general, moisture discrimination is performed with a high refractive index of the glass in order to realize TIR with acceptable geometric distortion. Low refractive index glass is also suitable with appropriate methods to correct geometric distortion and provide acceptable contrast frequency response (CTF) at a corresponding sharper angle of view.

The prism may contain SF-11 glass (refractive index = 1.785), easily accessible from manufacturers of high-quality glass. The angle of view, in one embodiment, as noted, is approximately 50 ° in order to perform a moisture discrimination. Glass with a low refractive index, for example, VK7 glass, can be used, and the plane of the object is viewed at a small angle, for example at an angle of approximately 65 °, to perform FTIR for skin and water applied to the plane of the object. Other transparent materials, glasses or plastics, for example, can be used instead of these special glasses.

In some embodiments, the mirror system 36 includes folding mirrors 42, 46, and 48. The mirrors reflect light, as shown, with a wavelength of about 450-650 nm produced by the light source 18.

The unique combination of the objective lens 22 and the design of the field lens 24 provides telecentricity of the rays directed to the plane of the object and optimizes the Modulation Transmission Function (MTF) in the lower part of the field of view, while at the same time keeping the MTF sufficiently high throughout the field of view. The plane of the object is illuminated through the illuminating face of the prism at an angle approximately equal to the angle of view (35-50 degrees).

In some embodiments, the thickness of the light source or means 18 is significantly reduced to provide a large cutout (area 20) under the illuminating face of the prism to accommodate the location of the finger when recording a rolling fingerprint.

In accordance with various embodiments, the light source 18 is a unique light panel or device. In some embodiments, the illumination source includes a panel designed as an assembly of a printed circuit having a plurality of small (approximately 1.6 mm × 0.8 mm × 0.6 mm) light emitting diodes (LEDs) with a wide range of illumination (approximately 140 -160 degrees half the intensity distribution profile). The light source includes a diffuser plate including a thin acrylic substrate of approximately 0.125 inches thick with light forming diffusers on each surface to receive light from the LEDs and project it onto the surface 14 in a uniform manner. Light-forming diffusers, such as these, are available from Luminit or Vikuiti on the flyer offers and / or elliptical patterns can be used. The focal point of the diffuser determines the thickness of the acrylic plate. The described light source provides a thin profile necessary to provide the required characteristics of the position of the finger, and provides full illumination over a wide area, necessary to illuminate a large - 5x5 inches - field of view. Light guide methods in which the incoming light on the sides of the transparent acrylic fiber device does not provide the same sufficient illumination, showing bright and dark areas that are difficult to compensate to achieve the desired uniformity of background lighting. White light LEDs or monochromatic LEDs can be used because the lens system is limited to skip a narrow wavelength range (such as blue, red or green spectrum). This allows the use of white light, which is more beneficial for the eyes than conventional sources of monochromatic light (such as green or red), which some users of the product find unsuitable for long-term use.

FIG. 2 and FIG. 3 illustrate views of a light panel or light source 18 according to various embodiments. Figure 2 shows a view of the light panel through the top of the prism 15, and Figure 3 shows an oblique projection of the light panel 18. A field or primary lens 24 is shown in Figure 2. The LED pattern projected onto the diffuser plate is shown schematically; one LED 25 is shown in a matrix of a plurality of LEDs. Figure 3 shows the assembly 28 of the printed circuit with a diffusing panel 26 and the shown projections 27 of the LED profile. In this embodiment, more than 100 LEDs are used to achieve uniform illumination. Figure 4 shows a side view of the light panel 18, and the prism 15, and the field lens 24 inside the housing 50. The vertical field of view is indicated at 29. A large area 20 or an ergonomic cutout outside the housing is available for positioning the finger during rolling the finger. The thin profile of the light panel 18 makes the space 20 available to accommodate the finger and thumb when rolling fingerprints. It is important to ensure that there is enough space under the prism to position the finger when rolling the fingerprints, to avoid getting the finger in the case and forcing the rolling finger to move in an undesirable way, resulting in smearing of the fingerprint.

In another embodiment, the lighting source 18 is an assembly of a background lighting panel including a light guide. 5 shows various components of such an assembly. A printed circuit board (not shown for clarity) includes LEDs to provide illumination and is located between the light guide or light guide 506 and the rear reflector 505. A heat-conducting foil 511 on the light guide 506 is also shown. The light emitted by the LEDs reaches either the light guide 506, which directs it to the diffuser plate 507, or the rear reflector 505, where it is reflected back into the light guide or light guide 506 and the diffuse plate 507. The prismatic films 508 and 509 are applied to the upper surface of the diffuser plate 507. One or more such prismatic films can be used, including a film, such as high brightness films (BEF), or other films, including a reversing prism or polarizing film, such as DBEF, can also yt used for the dispersion and increase the brightness. As in the case of the embodiment described above, white light emitting diodes or monochromatic light emitting diodes can be used in the light panel, since the lens system is limited to pass a narrow range of wavelengths (such as blue, red or green spectrum). This allows the use of white light, which is more beneficial for the eyes than conventional sources of monochromatic light (such as green or red), which some users of this product find unsuitable for long-term use. The panel is enclosed in a housing 510. Unlike the light panels in previous scanners that use optical fibers, the panel depicted in Figure 5 is very thin thanks to the use of LED backlight technology.

As indicated above, in some embodiments, the light panel display is thin enough to allow the scanner body to exactly match the front angle of the prism 15, while at the same time leaving room for positioning the finger and hand during recording of the rolled fingerprint. In some embodiments, the light panel is within 1 / 8-3 / 8 inches of thickness.

The optical design, including the telecentric field lens 24 and the lens system 22 of the lens, allows for an image with a larger field of view, necessary for palm prints, while allowing the image in the area of interest. The lens system of the lens is a multi-element lens of the lens. 6 shows a lens system 22 of an objective lens in accordance with some embodiments. As shown in FIG. 6, the lens system 601 of the lens may include a pair of doublets (achromats): a first doublet 621 and a second doublet 622. The doublet 621 includes lenses 623 and 624. The doublet 622 also includes two lenses 625 and 626 configured in this way. Each doublet acts as an achromatic lens, thus eliminating a substantial part of chromatic aberration. That is, the doublets provide lateral and axial color correction for wavelengths of interest, for example, from about 600 to 650 nm in one embodiment. The lens system 601 of the lens also includes two singlet lenses: a first singlet lens 627 and a second singlet lens 628. The lens mechanism also provides an aperture diaphragm in some embodiments.

In a particular embodiment, the lens system of the lens is a 6-element system with the following characteristics:

Magnification: 3,479x (image in the plane of the object)

Aperture diaphragm: 15.0 diameter; fixed

Spectral range: 625 nm +/- 20 nm; diffused red light

Spectral weighting: 1.0 @ 625 nm; 0.5 @ 605 and 645 nm

FOV: 127.0x84.9 (diagonal = 152.8) in object space

36.48x24.384 (diagonal = 43.88) in the image space

Distortion: 0.008% (nominal) +/- 0.20% in the space of objects

Field Curvature: Flat Field

Resolution limit: 55 cycles / mm COF (nominal) in the space of objects; (190 cycles / mm COF in image space)

MTF:> 30% @ 25 cycles / mm (Frequency response) everywhere in FOV

Transmittance:> 85%

Total lens length: 48.928 from top to top

Path length: 703.882 (from image to object)

Lens barrel length: 60.0 +/- 0.25 (includes extra length for a possible filter at the wide end)

Lens barrel diameter: 40.00 +/- 0.050

The first singlet lens: radius 29.300 mm cx, 81.280 mm ss; edge diameter 26,000 mm; thickness 4,000 mm; material: SK2

Second singlet lens: radius 102.900 mm ss, 42.093 mm cv; edge diameter 34,000 mm; thickness 5,000 mm; material: SK2

The first doublet lens: radius: 27.860 mm cx, 50.800 mm, 19.230 mm ss; edge diameter 26,000 mm, 26,000 mm, thickness 4,000 mm, 3.5 mm; Material: SK4, F8

Second doublet lens: radius: 19.230 mm ss, flat, 34,000 mm cx; edge diameter 34,000 mm, 34,000 mm, thickness 3,000 mm, 7,000 mm; material: F8, SK4

Other multi-element lens systems can be used to obtain front and rear focal lengths of various sizes and smaller blur spots for enhanced quality at a higher price. For example, a seven-element lens made of three singlets and two doublets, or, alternatively, made of three singlets, one doublet and a singlet with a high degree of curvature, can be used in accordance with various embodiments.

The field of view of the plane of the object is thus consistent with the system 38 of image sensors through color-corrected optics, including folding mirrors. The optics configuration is telecentric both on the object plane and the image plane to provide a wide area of high-quality optical performance, showing small blur spots throughout the FOV for the selected color wavelengths. The vertical FOV in various embodiments may be between 2 and 5 inches. In some embodiments, the image sensor system 38 includes one monochrome CMOS imager. In other embodiments, multiple imaging devices may be used. Color imaging devices may also be used, for example, one or a plurality of color CMOS imaging devices with a high pixel density can be used with an LED white light source (LED) and color-corrected optics, or can be used with a monochromatic light source with a color-corrected lens. In some embodiments, one or more CCD imaging devices are used in place of the CMOS imaging device (s). Also, in some embodiments, a 14 megapixel monochromatic imager is used. A CMOS or CCD monochromatic imager with more than 14 megapixels can also be used. In some embodiments, a 12 megapixel imager and an imager are mechanically blurred in steps of less than ½ pixels to form a raw image that can be formatted into a final 1000 ppi image. Similarly, in some embodiments, a smaller than 12 megapixels imager is used, and the imager is mechanically blurred by less than ½ pixels to form a raw image that can be formatted into a final 500 pixel image.

An image sensor or sensors provide digital output at a frame rate of approximately 12 frames per second or more. The transfer speed is high enough to avoid distortion (for example, 12 frames / second (fps) for rolled prints is higher than 8 fps for pressure prints and 4 fps for palm images). The sensors are tilted to perform Scheimpflug correction of keystone distortion and focus changes in the vertical FOV caused by a sharp angle of view.

7 illustrates an optical-mechanical embodiment of a system. The principal elements are shown in the sectional image: a light panel 78, a prism 75, a field lens 74, an objective lens 72, and a camera assembly 76. Also shown is an assembly 79 of an integrated DSP computer circuit board that controls image recording and provides communication with a central computer. In order to obtain the desired image sharpness (MTF) in the entire field of view, the lens system of the lens is designed with a unique purpose - to achieve high MTF over the entire field of view, but with a bias towards the lower area where the rolled fingerprints are recorded. 8A and 8B show MTF profiles over the entire field of view. The slope towards the bottom of the FOV is shown.

In some embodiments, the system is configured to roll fingerprints in the center of the lower region for high-quality execution. However, the implementation of MTF allows you to get acceptable results when rolling in any corner. An MTF in excess of 30% for 10 cycles per mm represents the corresponding performance data.

9 shows possible areas 901 that can be selected for rolling fingerprints. The area needed for rolling is 1.6 (width) by 1.5 (height) inches. Dimensions shown are approximate. Note that the field of view shown is a map of the plane of the object (about 5 x 5 inches) displayed on the imager. The shift of the compression coefficient of the near square field of view is a function of viewing the plane of an object through a prism at a TIR angle.

Specific embodiments of the system employ a 14 megapixel monochrome CMOS roll-up shutter imager (IBIS4-14000) manufactured by Cypress Semiconducter. This device provides addressability of the region of interest with increasing frame rate when the region of interest is less than the whole field of view. However, increasing the frame rate is a function where the area of interest is selected. In the example shown in FIG. 9, the highest frame rate increase is performed when the ROI is selected as the lower left corner. If the region of interest moves to the right, then the frame rate decreases to a minimum, and then increases again in the lower right corner. Therefore, the execution is optimal in the corners. Various embodiments of the system allow you to set the area of interest of rolling in any area in the lower part of the main field of view without ergonomic difficulties.

An area of interest larger than that shown for rolling fingers can also be assigned to record 4 pressed fingers (usually 3.2 × 3.0 inches or 3.2 × 2.0 inches). This is desirable to increase the frame rate and thereby to minimize the effects of motion when recording images of pressed fingers.

Optical devices are designed to make a small blur spot - about 25 microns. This gives two performance advantages: (1) a very high contrast when using an imager that provides excessive discretization of the field of view, such as when 550 ppi is set at the output of the system, and (2) good contrast when the system is designed for 1000 ppi at the output. In some embodiments, to obtain 1000 ppi of output, the image former may be mechanically blurred by ½ pixel in the horizontal and vertical axes relative to the image recorded at each position. 4 images can then be combined with embedded pixels for use in generating 1000 ppi images without interference and with high MTF with characteristics of 20 cycles / mm on the plane of the object.

In one embodiment, a 14 megapixel image with 4536 (horizontal) × 3024 (vertical) pixels supports a raw image format of approximately 900 pixels per inch horizontally × 600 pixels / inch vertically. This high MTF raw image is then scaled to 500 ppi, showing very high contrast.

In order to obtain flexibility in designating a region of interest for recording rolling, to optimize image recording in any region of interest and to provide optimal image processing in each region of interest, an integrated DSP computer 30 is provided as specified in the system design.

A DSP computer receives camera output, generates fingerprint images that meet certain FBI requirements, and provides images to a central computer for integration into a “record” consisting of a set of images and text data. This system is shown in FIG. 10.

As shown in FIG. 10, processing of image data from an image sensor or camera 1028 extracted from the image surface 1012 is performed on a special purpose digital signal processing (DSP) computer 1050. Computer 1050 receives image output from a fingerprint / palm or image sensor 1028. These processed image data meet certain FBI requirements, such as specifications of the FBI Appendix F. Processed images are provided to a central computer (not shown) through the Firewire 1054 line according to the IEEE 1394 standard for combining into a record containing a set of images and text data. Image capture of a computer 1050 may be performed using a technique such as that described in US Pat. No. 5,748,766 entitled "Method and apparatus for reducing blurriness of rolled fingerprints," or a technique described in US Pat. No. 4,933,976, entitled "Generation System images of rolled fingerprints "assigned to the assignee of this application, and which are incorporated herein by reference.

Computer 1050 also controls, as represented by control unit 1058, the operation of image sensor system 1028, and includes optical elements and camera assembly 1010. Optical elements of image system 1000 are represented by block 1060. In another embodiment of the invention, data may be transmitted to a central computer before being finalized. fingerprint shape. The final processing of the fingerprint would then be completed using software or a combination of software and hardware on a central computer.

Also, an optional handheld scanner can be used in conjunction with the 1000 image system. The hand scanner is controlled by a 1050 computer. The computer receives image output from a hand scanner. A handheld scanner may be of the type described in US Pat. No. 6,175,407, entitled “Device and Method for Optically Imaged Characteristics on the Surface of the Hand”, assigned to the assignee of this application, and which is incorporated herein by reference.

Many implementations and methods have been described. However, it will be understood that various modifications can be made to the described components and methods. For example, a favorable result can be obtained if the steps of the disclosed methods were performed in a different order or if the components in the disclosed systems were combined in various ways, or replaced, or supplemented by other components.

For example, the optical structure of an image system can use only one folding mirror or two folding mirrors. It is also possible, in one embodiment, to eliminate folding mirrors completely by reducing both the front and rear focal lengths of the objective lens and / or by packing the optical system in a longer case. The lens system of the lens may contain certain lens combinations other than two pairs of doublets and two singlets. For example, a combination of three pairs of doublets can be used to provide higher CTF across the larger FOV. Also, objects other than a finger can be displayed by the image device.

Additionally, instead of a single imaging device, a plurality of imaging devices can be used. In another configuration, the light source, as discussed, can be multi-color, providing more than one wavelength of light, through color-corrected optics, to activate more than one pixel color on a CMOS or CCD image device. For example, CMYK (cyan - magenta - yellow - black) the imager can be effectively illuminated by a light source, which would stimulate three of the four colors of the imager, but not the fourth. Color correction in optics would be easier due to the reduced dispersion of wavelengths that would need to be maintained, and the illumination could be accomplished by two-color LEDs.

Many embodiments of the invention have been described.

However, it will be understood that various modifications can be made without deviating from the essence and scope of the invention.

Claims (18)

1. A system for optical imaging of an object in a field of view, comprising:
an optical plate having a surface receiving an object;
a light source mounted to illuminate a surface receiving an object;
an image forming system having an image plane and installed to receive light from a surface receiving an object to form an image of an object on a surface receiving an object; and
a lens mechanism for focusing light from the surface receiving the object onto the image plane, the system being configured to record the image in the full field of view and to record the region of interest in the field of view, and the lens mechanism is a six-element lens; and
moreover, the imaging system is configured to provide an increased frame rate in the region of interest when the region of interest is less than the field of view. 2. The system of claim 1, wherein the object is a hand. 3. The system of claim 2, wherein the system is configured to record at least a fingerprint image and a fingerprint image. 4. The system according to claim 1, further comprising a folding mirror to direct light from the surface receiving the object into the lens mechanism. 5. The system according to claim 4, in which there are three folding mirrors. 6. The system according to claim 1, in which the imaging system further includes a monochromatic CMOS imager. 7. The system according to claim 1, in which produce images of 500 and 1000 pixels per inch. 8. The system of claim 1, wherein the light source is a monochromatic light source. 9. The system of claim 1, wherein the light source comprises an assembly of a background lighting panel including a light guide. 10. The system of claim 1, wherein the light source comprises a panel having a thickness of not more than 3/8 inch. 11. The system according to claim 1, additionally containing an area under the light source for positioning the hand or finger and thumb. 12. A system for optical imaging of a hand, comprising:
an optical plate having a surface receiving an object;
a light source mounted to illuminate a surface receiving an object;
an image forming system having an image plane and installed to receive light from a surface receiving an object to form an image of an object on a surface receiving an object;
a lens mechanism for focusing light from the surface receiving the object onto the image plane, the system being configured to record palm images and fingerprint images in the field of view or region of interest within the field of view, and the lens mechanism includes two doublets and a pair of singlets ; and
moreover, the imaging system is configured to provide an increased frame rate in the region of interest when the region of interest is less than the field of view. 13. The system of claim 12, wherein the system is configured to record at least palm images and images of rolled fingerprints. 14. The system of claim 12, further comprising an area under the light source for positioning the thumb or finger. 15. The system of claim 12, wherein each of the x and y dimensions of the surface receiving the object is at least about 5 inches. 16. A method of imaging a hand, comprising:
hand reception on the surface of the receiving object of the optical plate;
illumination of the surface receiving the object with a light source;
collecting light from a surface receiving an object;
focusing the collected light on the image plane of the image forming system using a lens mechanism including a six-element lens or a pair of doublets and a pair of singlets to form a hand image that is recorded within the field of view or region of interest within the field of view, the image containing a palm image hands and at least finger; and
providing an increased recording frame rate in the region of interest when the region of interest is smaller than the field of view. 17. A system for optical imaging of an object in a field of view, comprising:
an optical plate having a surface receiving an object;
a light source mounted to illuminate a surface receiving an object;
an image forming system having an image plane and installed to receive light from a surface receiving an object to form an image of an object on a surface receiving an object; and
a lens mechanism for focusing light from the surface receiving the object onto the image plane, the system being configured to record an image within the field of view and to record an area of interest within the field of view, and the lens mechanism includes a six-element lens or two doublets and a pair singlets; and
moreover, the imaging system is configured to provide an increased frame rate in the region of interest when the region of interest is less than the field of view. 18. The system of claim 17, further comprising three folding mirrors to direct light from the surface receiving the object into the lens mechanism.

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