Fingerprint capture device, system and method

Abstract

The fingerprint capture device includes a removable, magnetically attached finger aperture selector that facilitates reconfiguration of the device to image a wide range of finger sizes and body regions. The device housing and selector are also configured for one-handed use based on the angle and location of the imaging actuator and selector relative to the device handle. The device includes a camera calibration mount that facilitates adjustment of camera alignment. Software usable with the device can normalize fingerprint features based on the age and personal characteristics of the subject being imaged.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Patent Application No. 63 / 410561, filed September 27, 2022, which is incorporated herein by reference in its entirety. This application is also related to U.S. Patent No. 10,496,870, filed March 6, 2018, U.S. Patent No. 11,003,883, filed March 7, 2018, U.S. Publication No. 2022 / 0071489, filed December 20, 2019, and PCT Publication No. 2020 / 132645A1, filed December 20, 2019, all of which are incorporated herein by reference in their entirety. [Background technology]

[0002] The present invention relates generally to fingerprinting, and more particularly to a method and apparatus for contactless fingerprinting of newborns, infants, toddlers, children and adults. Summary of the Invention [Means for solving the problem]

[0003] In one embodiment, the fingerprint capture device includes a removable, magnetically attached finger aperture selector that facilitates reconfiguration of the device to image a wide range of finger sizes and body regions. The device housing and selector are also configured for one-handed use based on the angle and location of the imaging actuator and selector relative to the device handle. The device includes a camera calibration mount that facilitates adjustment of camera alignment. Software usable with the device can normalize fingerprint features based on the age and personal characteristics of the subject being imaged.

[0004] In one embodiment, a fingerprint entry system is provided, comprising: A main housing is provided, an elongated handle including a longitudinal axis; a rotating hub integrally formed with an elongated handle, the hub comprising: an upper convex surface; an imaging aperture in the upper convex surface; a circular flange surrounding the upper convex surface, the circular flange having an upper wavy surface; a central hub magnet located at the center of the rotating hub; The fingerprint input system also a plurality of peripheral hub magnets equally spaced around the circular flange, each hub magnet being located at the same hub radial distance from the center of the rotating hub; An actuator installed in front of the elongated handle, an imaging assembly located inside the elongated handle and including an imaging shaft; a removable rotation aperture top configured to form a rotation interface with the rotation hub, the selector comprising: a concave lower surface configured to form a complementary rotational interface with an upper convex surface of the hub; a plurality of finger-receiving apertures, each aperture being a different size and including a chamfered peripheral edge disposed in the aperture plane; a plurality of flanges configured to surround the concave lower surface and extend radially outward beyond the circular flange of the rotation hub, the plurality of flanges being radially offset from the plurality of finger-receiving apertures, each of the plurality of flanges including a wavy surface complementary to a portion of the wavy surface of the circular flange of the rotation hub; a central top magnet located at the center of the removable rotating aperture top, the center of the removable rotating aperture top and the center of the rotating hub defining an axis of rotation; and a plurality of peripheral top magnets equally spaced around the plurality of flanges, each of the plurality of top magnets being located at the same top radial distance from the center of the top.

[0005] In another embodiment, a fingerprint entry system is provided, comprising: A main housing is provided, an elongated handle including a longitudinal axis; a rotating hub integrally formed with an elongated handle, the hub comprising: a hub interface surface; Center and an imaging aperture on the surface of the hub; a first plurality of alignment structures equally spaced about the rotating hub, each of the plurality of alignment structures being located at the same hub radial distance from the center of the rotating hub; The fingerprint input system also an actuator located on an elongated handle; an imaging assembly located inside the elongated handle and including an imaging shaft; a removable rotation aperture top configured to form a rotation interface with the rotation hub, the selector comprising: a top interface surface including a center configured to form a complementary rotational interface with an upper convex surface of the hub, the top interface surface including a center, the center of the top and the center of the hub defining an axis of rotation; a plurality of finger-receiving apertures, each aperture being a different size and including a chamfered peripheral edge disposed in the aperture plane; a plurality of flanges surrounding the top interface surface and configured to extend radially outward beyond the rotation hub, the plurality of flanges being radially offset from the plurality of finger-receiving apertures; A second plurality of alignment structures arranged in a configuration complementary to the first plurality of alignment structures mounted on the rotating hub. The apparatus may further include an adjustable camera alignment mount. The adjustable camera alignment mount may include a frame and three adjustment screws. The frame may include a polygonal shape with four sides and four corners, with a first of three adjustment screws located at the center of one of the four sides and second and third adjustment screws located at two of the four corners furthest from the first screw. The adjustable alignment mount may be releasably coupleable to the imaging assembly via mount magnets attached to the frame. The imaging assembly may be positioned within a frame opening in the frame. Three magnets may be embedded in the frame and three adjustment screws may be magnetically attachable to the magnets. Three adjustment screws may be attached to the main housing. The system may further include a first heat sink thermally coupled to the imaging assembly. The system may further include a lighting assembly including multiple light sources within the main housing. The lighting assembly may include a circular base. The system may further include a light diffuser above the lighting assembly. The system may further include an illumination heat sink thermally coupled to a lower surface of the illumination assembly. The system may further include a camera support between the imaging assembly and the adjustable camera alignment mount. The first plurality of alignment structures and the second plurality of alignment structures may each comprise a magnet. The system includes a third plurality of alignment structures mounted on the rotating hub; The device may further comprise a fourth plurality of alignment structures complementary to the third plurality of alignment structures and mounted on the removable rotating aperture top. The third plurality of alignment structures may comprise a plurality of alternating wavy or sloping surfaces, and the fourth plurality of alignment structures may comprise a plurality of alternating wavy or sloping surfaces complementary to the third plurality of alignment structures. A third plurality of alignment structures may be located along an upper peripheral circular surface of the rotating hub. A fourth plurality of alignment structures may be located on the underside of the plurality of flanges. The system may further comprise an elongated planar measurement tool including a plurality of different apertures arranged successively by size along the tool. The measurement tool may further include a plurality of order markings corresponding to a plurality of different apertures. The fingerprint device described herein is designed to collect platen-free fingerprints and other body parts in a consistent manner across a wide range of ages and body sizes. This system design addresses many of the challenges associated with fingerprint collection using traditional contactless devices, primarily cell phone camera biometric systems. In cell phone camera systems, the camera and the subject's finger are held independently in free space. The subject holds their finger in front of the camera, and the distance between the finger and the camera can vary, changing the image size and spatial resolution of the finger's pixels. Each cell phone has a focal length that must be adhered to in order to capture a clear image. Before the fingerprint image can be analyzed and saved as a fingerprint template, the inconsistent spatial resolution must be normalized to a standard 500 pixels per inch for compatibility with other automated biometric identification systems (ABIS). Because the finger is held in free space in front of the camera, users must be careful to ensure that their fingerprint is properly oriented and aligned with the camera. Additionally, there are concerns about what may be visible in the background behind the subject. Bright lights and / or similarly colored background scenes can make it difficult to separate the finger image. Camera cell phone fingerprint systems do not use specific hardware, but rather software applications hosted on various cell phone devices. Each cell phone device manufacturer and model will have a different total number of pixels, optical resolution, field of view, light source power, and light source spectral characteristics. All of these variables must be taken into account with the fingerprint software program that collects finger images using a cell phone. Cell phone-based systems are designed for adult use only and do not have correction features for use with infants and young children.The device herein is designed to eliminate or minimize the aforementioned challenges, including use with all age groups from infants to adults, and is an improvement over previously developed designs described in U.S. Patent No. 10,496,870, U.S. Patent No. 11,003,883, U.S. Publication No. 2022 / 0071489, WO 2020 / 132645A1, and the literature (Saggese S, Zhao Y, Kalisky T et al. Biometric recognition of newborns and infants by non-contact fingerprinting: lessons learned, Gates Open Research 2019, 3:1477). [Brief explanation of the drawings]

[0006] [Figure 1A] FIG. 2 is a left side view of one embodiment of a fingerprint capture device. [Figure 1B] FIG. 2 is a right side view of one embodiment of a fingerprint capture device. [Figure 1C] FIG. 2 is a front view of the device of FIGS. 1A and 1B. [Figure 1D] FIG. 2 is a rear view of the device of FIGS. 1A and 1B. [Figure 1E] FIG. 2 is a top view of the device of FIGS. 1A to 1D. [Figure 1F] FIG. 2 is a bottom view of the device of FIGS. 1A to 1D. [Figure 1G] FIG. 2 is an exploded perspective view of the device of FIGS. 1A to 1F. [Figure 1H] FIG. 2 is a top perspective view of the device of FIGS. 1A to 1F. [Figure 1I] 1H shows the device of FIG. 1H in use. [Figure 1J] 10 shows a schematic of the alignment of the rotating aperture top with the main housing. [Figure 2A] 10 is a schematic top view of the alignment of the rotating aperture top and the magnetic interface. [Figure 2B] 10A and 10B show schematic diagrams of the rotation of the rotating aperture top. [Figure 2C]2B is a schematic top view of the realignment of the rotating aperture top in a different position than in FIG. 2A. [Figure 2D] FIG. 1 is a side view of the device showing the peripheral interface between the hub and the rotating top, with the rotating top in a partially seated position. [Figure 2E] FIG. 1 is a side view of the device showing the peripheral interface between the hub and the rotating top, with the rotating top in a fully seated position. [Figure 3A] 10A-10C are rear perspective views of fingerprint capture devices mounted on various rotating aperture tops. [Figure 3B] 10A-10C are rear perspective views of fingerprint capture devices mounted on various rotating aperture tops. [Figure 3C] 10A-10C are rear perspective views of fingerprint capture devices mounted on various rotating aperture tops. [Figure 4A] FIG. 1 is a perspective view of one exemplary embodiment of a rotating aperture top. [Figure 4B] FIG. 10 is a top view of one exemplary embodiment of a rotating aperture top. [Figure 4C] FIG. 10 is a bottom view of one exemplary embodiment of a rotating aperture top. [Figure 4D] FIG. 10 is a side view of one exemplary embodiment of a rotating aperture top. [Figure 4E] FIG. 10 is a perspective view of another exemplary embodiment of a rotating aperture top. [Figure 4F] FIG. 10 is a top view of another exemplary embodiment of a rotating aperture top. [Figure 4G] FIG. 10 is a bottom view of another exemplary embodiment of a rotating aperture top. [Figure 4H] FIG. 10 is a side view of another exemplary embodiment of a rotating aperture top. [Figure 4I] FIG. 10 is a perspective view of yet another exemplary embodiment of a rotating aperture top. [Figure 4J] FIG. 10 is a top view of yet another exemplary embodiment of a rotating aperture top. [Figure 4K]FIG. 10 is a bottom view of yet another exemplary embodiment of a rotating aperture top. [Figure 4L] FIG. 10 is a side view of yet another exemplary embodiment of a rotating aperture top. [Figure 5A] FIG. 10 is a longitudinal cross-sectional view of the main housing showing the optical centerline. [Figure 5B] FIG. 2 is an orthogonal side view of a longitudinal section of the main housing. [Figure 5C] FIG. 1 is an orthogonal side view of a longitudinal cross-sectional view of a fully assembled fingerprint capture device. [Figure 5D] FIG. 10 is a perspective view of the main housing showing the alignment of the camera and aperture. [Figure 6A] FIG. 13 is a perspective view of a fixed optical configuration relative to a rotating aperture top. [Figure 6B] FIG. 6B is a side view of a fixed optical configuration relative to the rotating aperture top of FIG. 6A. [Figure 6C] FIG. 6C is a cross-sectional perspective view of a fixed optical configuration for the rotating aperture top of FIGS. 6A and 6B. [Figure 6D] FIG. 6D is a cross-sectional side view of a fixed optical configuration relative to the rotating aperture top of FIGS. 6A-6C. [Figure 7A] FIG. 2 is a perspective exploded view of the imaging configuration. [Figure 7B] FIG. 7B is a side exploded view of the imaging configuration of FIG. 7A. [Figure 7C] FIG. 1 is a perspective view of a fixed optical configuration. [Figure 7D] FIG. 7D is a side view of the fixed optical configuration of FIG. 7C. [Figure 8A] FIG. 1 shows a perspective view of a camera alignment configuration. [Figure 8B] 8B shows a perspective view with hidden lines and magnet placement for the camera alignment configuration shown in FIG. 8A. [Figure 8C] 8C shows a perspective view of the camera alignment configuration shown in FIGS. 8A and 8B and illustrates a variable alignment angle. [Figure 9A] 1 is a schematic overlaid outline of seven finger apertures. [Figure 9B] FIG. 10 shows a top view of the finger selector guide. [Figure 10A] A perspective view of the dot locations on the rotating aperture top is shown. [Figure 10B] A perspective view of the dot locations on the rotating aperture top is shown. [Figure 10C] A perspective view of the dot locations on the rotating aperture top is shown. [Figure 10D] 10B shows a captured image of the aperture and dot of FIG. 10A. [Figure 10E] 10B shows a captured image of the aperture and dots of FIG. 10B. [Figure 10F] 10C shows a captured image of the aperture and dots of FIG. 10C. [Figure 11A] All dot placements are shown on the top of the rotating aperture for infants. [Figure 11B] shows all dot placements on the adult rotating aperture top. [Figure 11C] Shows all dots superimposed along the bounding box. [Figure 12A] 1 shows the boundary lines used to detect the aperture size. [Figure 12B] 1 shows the boundary lines used to detect the aperture size. [Figure 12C] 1 shows the boundary lines used to detect the aperture size. [Figure 13A] 1 shows images of a finger taken with different aperture sizes. [Figure 13B] 1 shows images of a finger taken with different aperture sizes. [Figure 13C] 1 shows images of a finger taken with different aperture sizes. [Figure 13D] 1 shows images of a finger taken with different aperture sizes. [Figure 13E] 1 shows images of a finger taken with different aperture sizes. [Figure 13F] 1 shows images of a finger taken with different aperture sizes. [Figure 14A] A fingerprint image of the birth date is shown. [Figure 14B] A fingerprint image of a one-year-old child is shown. [Figure 14C] Showing adult fingerprints. [Figure 14D] 14B shows a normalized minutiae map of the birth date fingerprint image of FIG. 14A. [Figure 14E] FIG. 14B shows a normalized minutia map of the fingerprint image of the one-year-old child. [Figure 14F] FIG. 14C shows a normalized minutia map of the adult fingerprint image. [Figure 15A] This shows data on the relationship between pinky finger size and age. [Figure 15B] Data on the relationship between middle finger size and age are presented. [Figure 16A] The original image of the finger is shown. [Figure 16B] The binary mask of the aperture used is shown. [Figure 16C] 1 shows an image of a finger after applying a mask to the original image. [Figure 16D] 1 shows a magnified image of a finger as it would be presented to a user. [Figure 17A] An original image of a finger is shown, and automatic core detection is demonstrated. [Figure 17B] Five different positions are suggested to the user for placing the core during image acquisition. [Figure 18] 1 is a flowchart of the system operation. [Figure 19A] 10 is a perspective view of another embodiment of the fingerprint capture device, with the rotating top separated from the main housing. [Figure 19B] 19B is a detailed longitudinal cross-sectional view of the upper region of the fingerprint capture device of FIG. 19A. [Figure 19C] FIG. 19B is an exploded view of exemplary components of the device of FIG. 19A. [Figure 19D] FIG. 19B is a detailed perspective view of the rotating hub and optics cover of the main housing of FIG. 19A. [Figure 19E] FIG. 19B is a perspective cross-sectional view through the main housing of FIG. 19A. DETAILED DESCRIPTION OF THE INVENTION

[0007] The device includes a self-contained camera system with a dedicated camera with fixed focal length optics, a built-in light source, and a fixed optical configuration that positions a subject's finger (or other body part) at a specific location using an adjustable aperture through which the subject places the finger. The device 100 is small enough for one-handed operation. Figures 1A-1F depict an example overall design, including the appearance of the assembled device 100, including a main housing 102, a rotating top 104a configured to select the size of finger-support apertures 106a-d, a trigger or actuator 108 for initiating image collection, and a communications link 110, such as a USB cable, connecting the device to a computer. In some variations, a wireless communications link via Bluetooth or another wireless communications protocol may be provided. Figure 1G shows an exploded view of the device 100, showing the internal and external system components. Figure 1H shows the device in position for use, and Figure 1I shows the device being held by a user while the subject's finger is moved back and forth over the aperture for image collection.

[0008] In this exemplary embodiment, the main housing 102 may include two-piece shells 102a, 102b configured to form a complementary fit with one another and define an interior cavity for housing the camera assembly 112 with lens 114, lighting assembly 116, and window / diffuser. The two shells 102a, 102b together form a handle region 120 of the housing 102, with one shell 102a including a rotation hub 122, or both shells together forming a rotation hub 122 to which the rotating top 104a is removably attached. Additionally, the device may also include a camera mount assembly 170 (which can be used to adjust the alignment of the camera assembly 112 during manufacturing and / or maintenance), one or more heat sinks within the camera assembly and / or lighting assembly, additional optical devices such as a camera aperture structure 152 and an aperture support structure 154, and an optically transparent window 156 and window seal to protect the contents of the device 100.

[0009] The main housing 102 may include a generally elongated shape, with a proximal end 124 from which the wired communication link or cable 110 extends, a distal end 126 at which the rotation hub 122 is mounted, a ventral surface 128 at which the actuator 108 may be mounted, and a dorsal surface 130. The main housing 102 may also include grip structures on its exterior surface to reduce slippage and improve stability when using the device 100. In this particular embodiment, a flat palm grip structure 132 is optionally provided on the dorsal surface to increase contact with the user's flexed palm when gripping, which can reduce torque or rotation of the device 100 during use.

[0010] As shown in FIG. 1E, the rotating top 104a includes a generally dome-shaped structure 134a with multiple apertures 106a-d spaced about a center of rotation 136a of the top 104a. Each aperture 106a-d has a different size, but the center-to-center spacing between adjacent apertures 106a-d is the same, and each aperture 106a-d has the same aperture plane angle relative to a central axis of rotation passing through the center of rotation 136a of the rotating top 104a. This arrangement allows a user to maintain imaging consistency with the camera assembly regardless of the aperture 106a-d selected. The top 104a may be provided with indicia 138a to facilitate identification of the aperture size range, subject age, and / or body part associated with each rotating top. A series of interleaved flanges 140a and finger recesses 142a may be present near the edge or periphery of the dome structure 143a to facilitate rotation of the rotating top 104a to select the desired aperture 106a-d. The flange 140a may have a radially outward height of 3 mm to 4 mm, 3 mm to 8 mm, or 2 mm to 10 mm, a circumferential length of 20 mm to 25 mm, 22 mm to 30 mm, or 15 mm to 35 mm, and a longitudinal height of 8 mm to 10 mm, 6 mm to 15 mm, or 5 mm to 15 mm. The recesses may have corresponding complementary radially outward and longitudinal heights to the flange 140a, but a circumferential length that may be the same as, less than, or greater than the flange 140a, and have a circumferential length of 10 mm to 13 mm, 8 mm to 20 mm, or 11 mm to 15 mm. To facilitate image capture, the center of each recess 142a may be radially aligned with the center of each aperture 106a-d, except for the recess 142a located adjacent to the landmark 138a (if present).

[0011] The detachable attachment between the hub 122 and the top 104a may be provided by a ball latch or snap - type mount, or, in this particular embodiment, as shown in FIG. 1J, may be provided by a plurality of complementarily - arranged magnets on the hub 122 and the rotating top 104a. The plurality of magnets on the hub 122 may include a central magnet 144 and peripheral magnets 146a - e spaced equidistantly around from the central magnet 144. The complementary rotating - top magnets include, as shown in FIG. 4C, a rotating - top central magnet 148 and peripheral magnets 150a - e spaced equidistantly around from the rotating - top central magnet 148. The magnets are arranged around the outer edge of the top, not only connecting it to the housing, but also providing a reproducible discrete rotational position for aligning each individual aperture to an exact location within the camera's FOV (field of view). The central magnet pair 144, 148 on the axis of rotation located at the center of the rotating top 104 functions like a shoulder screw or an axle, preventing the rotating top 104a from moving laterally. FIG. 1J shows a configuration with five magnet pairs, one set on the top (neodymium with a diameter of 3 / 16” (inch)×3 / 16” thickness, 2.2 pounds (lbs.) of tensile force per magnet), and a second set set within the main housing (neodymium with a diameter of 3 / 16”×1 / 8” thickness, 1.6 pounds of tensile force per magnet). The typical tensile strength using six magnet sets on the main housing has been tested up to 5 pounds, so when the magnets are aligned, the top is firmly fixed to the body. The top has a diameter of about 2 inches and fits within the average grip size of an adult hand. The shear strength of the magnet set between the top and the main housing is <TBD pounds. At this level of force, the user can rotate the top using the thumb and index finger of the hand holding the device, as shown in FIG. 1I. The strength of the magnets is selected to hold the top firmly, and this shear force can be easily overcome to rotate the top to the next position using the thumb and index finger. One ability provided by this magnetic configuration is the ability to easily remove the rotating top and replace it with another top having a different size or configuration, thereby allowing one base device to accommodate a wide range of sizes and body parts of the scanning target.In some further variations, the interface between the rotating top and the rotating hub may optionally include complementary mechanical detents and protrusions to facilitate alignment of the aperture in the rotating top with the imaging aperture in the hub. The detents may be located on either the hub or the top, and the protrusions may be located on either the hub or the top. In another embodiment, complementary central axles and central openings may be provided between the hub and the top to facilitate alignment of the hub and the top and potentially resist inadvertent separation of the hub and the top. In some variations, the axles and openings may be provided in addition to or instead of the central magnets in the hub and the top.

[0012] 2A-2C show how the rotating top 104a can be adjusted to access various aperture positions. When the magnets 146a-e, 150a-e are all aligned, as indicated by the arrows, the top 104a is centered in the camera's field of view (FOV) and aligned with one of the apertures, e.g., aperture 106b in FIG. 2A. The magnets 146a-e, 150a-e are strong enough to hold the top 104a in place, but when a lateral force is applied, the magnetic attachments of the peripheral magnets 146a-e, 150a-e rotate and separate (FIG. 2B), allowing for easy rotation until the magnets self-align again and automatically settle into the next or nearest aligned position, eliminating the need for the user to align the next aperture, e.g., aperture 106a, as shown in FIG. 2C. However, if the rotation of top 104a stops prematurely and magnet pairs 146a-e, 150a-e are misaligned, top 104a can be easily removed and replaced with another top, such as top 104b or 104c, shown in Figures 3B and 3C, respectively. The example in Figures 2A-2C shows five magnet pairs 146a-e, 150a-e, which create five rotational positions. Alternative embodiments may include more or fewer magnet pairs, resulting in a greater or lesser number of rotational positions. A five-position top strikes a balance between maximizing the number of positions and the device's diameter. The position with marker 138a can be used as a storage position to prevent debris from contacting the camera aperture or window. Increasing the number of spots requires increasing the diameter of the top to fit the aperture. The current design has a diameter that fits comfortably within the diameter of an adult's grip. The size of the aperture also affects the required diameter; a top with only a smaller aperture can have more than five positions without increasing the diameter and not compromising the one-handed operability of the device. Six- or seven-position tops may also be used without increasing the diameter if the aperture is small enough to fit.

[0013] To further facilitate alignment of the rotating top 104a with the hub 122, or to bias the rotating top 104a toward an aligned position between the hub magnets 146a-e and the rotating top magnets 150a-e, the rotating top 104a and hub 122 may have complementary wavy or alternatingly sloped inclined surfaces 160, 162, as shown in Figures 2D and 2E, such that when the rotating top 104a is placed on the hub 122, the attractive forces between the central magnets 144, 148a of the hub 122 and the top 104a minimize the gap distance between the central magnets 144, 148a (shown in Figures 1J and 4C) and the top 104a. The wavy or alternating sloped surfaces 160, 162 bias the top 104a to slide and rotate to minimize the gap distance, thereby moving the rotating top 104a to a position where the peripheral magnets 150a-e are closer to the peripheral magnets 146a-e of the hub 122a, bringing the rotating top 104a into perfect alignment. The wavy or alternating sloped surface 160 of the hub 122 may be mounted on a ring-like or annular surface 164 that surrounds a central dome 166 of the hub 122, on which the peripheral hub magnets 146a-e are mounted. Together, the magnets and wavy surfaces facilitate selective alignment of the apertures 106a-e of the top 104a with the imaging aperture 167 of the hub 122. Corresponding wavy or alternating sloped surfaces 162 of the rotating top 104a may be located along the underside of the flanges 140a-e and / or the underside of the rotating top 104a adjacent the recesses 142a-e.

[0014] Automatic alignment with multiple magnets provides the primary method for centering the aperture in the camera's FOV (field of view). The main housing and top are designed so that pairs of magnets are close together without touching each other. This reduces the strength of these magnets, allowing the user to easily rotate the top to its next position. To provide additional precision in alignment, the housing and rotary dial have an interlocking mechanism between the top and housing, further helping to maintain accurate and repeatable rotational alignment of the top and main housing.

[0015] When used on newborns and infants, the size of the device and the rotating top magnetic design assist the biometric human in collecting fingerprints. In adult-only systems, the subject can interact with the device. For infants, the device must be carried to the subject, and the biometric human must align the subject's fingers with one hand and interact with the device with the other. The biometric human can hold the subject and perform all functions of the device (e.g., rotate the top to obtain the best aperture size for a particular finger and initiate image collection without releasing the subject's hand).

[0016] To use a fingerprint device across a wide range of ages, i.e., neonates, infants, children, and adults, the device must be configured to properly support various finger sizes. This is achieved by having apertures of various sizes to support various finger sizes. If the aperture is too small, the scanned area will not yield enough visible fingerprint minutiae (ridge endings and bifurcations) to detect for accurate analysis; if it is too large, the finger will fall into the device and not lie flat on the image plane, allowing external light to enter the sample chamber. When scanning each subject's finger, an appropriately sized aperture 1) supports the finger, 2) allows an unobstructed view of the finger by the camera, 3) positions the finger within the fixed focal range of the optical system, 4) positions the finger at a known distance with a known optical resolution, and 5) blocks external light sources from reaching the camera.

[0017] Figure 9A is a schematic diagram outlining seven apertures 1, 2, 3, 4, 5, 6, and 7, spanning the usable finger size range from newborn to adult, each positioned at a common center. Table 1 lists the aperture lengths and widths, sized proportionally to the range between the smallest diameter of a newborn's little finger (Figure 15A) and the teen / adult middle finger size (Figure 15B) when the finger is fully grown. Figure 15A is a data graph showing the mean, 5th percentile, and 95th percentile ranges for the diameter (or width) of a newborn's fifth or little finger, which can be as small as 5 mm and increase to a maximum of 13 mm at age 13. Similarly, Figure 15B shows that the width size of the third or middle finger varies from 6 mm to 15 mm for the same age range, based on anthropometric data published in the University of Michigan Highway Safety Research Institute's Physical Characteristics of Children Report (UM-HSRI-BI-75-5), Final Report (May 31, 1975).

[0018] [Table 1]

[0019] These sizes are selected to span this range in seven steps, although any other dimension or combination of dimensions may be used in a particular application. Ruler 900 may comprise cardboard or a rigid polymer and is provided with successively spaced apertures 902a-g and corresponding indicia 904a-g to facilitate sizing the desired aperture for a particular subject's finger, with apertures 902a-g selected to support the largest finger width without the finger passing through aperture 902a-g. Each of these apertures 902a-g has a diameter corresponding to the widths listed in the table above (5.5 mm, 7 mm, 8.5 mm, 10 mm, 12.25 mm, 13.4 mm, 15.25 mm). In other variations, aperture widths may range from 5 to 16 mm, 4 to 18 mm, or 3 to 20 mm and may be provided using 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 apertures. Exemplary indicia 904a-g on ruler 900 include numbers, although letters or other symbols may also be used, and may correspond to indicia on rotating tops 104a-c adjacent each of apertures 106a-I or rotating top indicia 138a-c.

[0020] Figures 3A-3C show three different examples in which device 100 is configured or provided with a series of rotating tops 104a-c configured with a range of aperture sizes for specific applications. Within the set of apertures provided on these tops 104a-c, the apertures are each different sizes, although in other variations, there may be overlapping size ranges between the different tops. Figure 3A shows top 104a attached to device 100 intended for neonates and children, including apertures #1, #2, #3, and #4 from Table 1, with the closed position indicated by indicia 138a. This top 104a is also shown in Figures 4A, 4B, 4G, and 4J. Figure 3B shows top 104b attached to device 100 intended for adolescents and adults, with apertures #4, #5, #6, and #7 from Table 1, with the closed position indicated by indicia 138b. This top 104b is also shown in Figures 4C, 4D, 4H and 4K.

[0021] FIG. 3C shows an optional top 104c configured to be used to properly position a subject's hand for scanning the palmar side directly beneath the fingers. The "fin" structure 168 of the top 104c is positioned at the top of the aperture 106i's FOV, allowing the interdigital folds (i.e., webbing) between two fingers to be placed against either side of it, aligning the hand and imaging the palmar side. In this top 104c design, the aperture is fully open, imaging the largest possible area of ​​the finger pads. A wide, angled flange 140k adjacent to the aperture 106i may be provided to further support the subject's hand or palmar side during image acquisition. This top 104c is also shown in FIGS. 4E, 4F, 4I, and 4L. The inner edges of the apertures 106a-h may be sharp, angled, or include rounded edges. It is envisioned that the rounded edges may reduce light shadows near where the imaged finger contacts the inner edge of the aperture 106a-h by allowing more direct or indirect light at the inner edge.

[0022] The locations of the feature points on the finger are within an area roughly similar to the shapes of apertures 1-7 shown in FIG. 9A, which include a generally elliptical or oval shape with a smaller distal end and a larger base. The shapes of apertures 106a-h on tops 104a and 104b can be configured to support the finger while leaving most of the feature points exposed. Because the tip of a finger is often smaller than the knuckle area, rectangular apertures do not support the finger well. The three-dimensional shape of the apertures mimics the rounded shape of the finger, so the finger is supported by edges that conform to the surface of the finger. FIGS. 4A-4D and 4G-4K show that the shapes of apertures 106a-h mimic the shape of a finger, including a generally elliptical or oval shape with a smaller distal end and a larger base, and have the dimensions listed in Table 1. Each aperture 106a-h is configured with a distance from the camera that places the center of the aperture, i.e., the finger (centered from the fingerprint to the nail), generally in the desired focus. Since fingers all come in different shapes and sizes, this is a general guideline and the actual finger position will vary. The device can image over a wide depth range, with good focus from 10 mm below the aperture to the top of the aperture, keeping the fingerprint in focus.

[0023] The main housing 102 has several features that simplify manufacturing and ensure that the optical alignment between the camera and finger placement is stable and consistent from device to device. The main housing 102 comprises a main shell 102a and a shell cover 102b, where the main shell 102a may be a single piece that is printed, cast, or machined and includes relatively more alignment and retention features than the shell cover 102b. Using a single piece for the main shell 102a allows for more precise dimensional control than using multiple pieces for various functions, which can provide greater precision and repeatability when positioning internal components to achieve the desired camera alignment.

[0024] As shown in FIGS. 5A-5D , the main shell 102a includes features for supporting optical components, including the camera assembly 112 with integrated lens, camera mount 170, and LED PCB 116 with light diffuser, so that all of these components are sufficiently aligned along the optical centerline 500 to pass through the imaging aperture 167 of the rotating hub 122 and the attached rotating top 104b. The main shell 102 may also include features to prevent scattered LED light from reaching the camera, such as light-tight inner walls, light-absorbing or light-diffusing paint, or other features that prevent external light sources from leaking into the device via a separate aperture on the top. The rotating hub 122 includes a concave, rounded chamber 172 below the hub 122, which helps homogenize the light for diffuse illumination.

[0025] By fixing all of the optical components and fixing the finger position, the optical resolution, field of view, light source intensity, and spectral content all remain constant or have reduced variation, and the finger can be held at the desired focal location for each image collection. Furthermore, when a finger is placed in the aperture, the disclosed design reduces extraneous light sources that may obscure the finger, maintaining a consistent background (non-finger) portion of the image. The result of using all of these mechanisms is the collection of images with increased image quality and contrast. Figures 6A-6D are diagrams of the subassembly 600, with the exemplary top 104b showing the alignment of the various optical components 112, 114, 116, and 118, each position set by the main shell 102a. 7A-7D show additional views in which a pinhole aperture structure 700 and pinhole aperture support 702 are added on top of a standard f / 3 lens 114 to increase the f / # to f / 10, thereby increasing the depth of focus of the camera assembly 112 and allowing a clear image of the finger surface to be captured even when the finger is curved and different parts of the finger are at different distances from the camera assembly 112.

[0026] For the camera assemblies 112, only small alignment adjustments are required because the main shell 102a provides xyz alignment with a sufficiently high degree of precision. However, variations within the camera assemblies 112 can benefit from finer angular alignment. For example, the camera chip, lens mount, lens, aperture, and camera mount will not always have exactly the same relative positions for all camera assemblies 112, causing the camera's center of field of view to vary between each camera / optics subassembly. To compensate for this, slight angular alignment and / or Z-axis translation adjustments can be made to each camera assembly to improve alignment and / or depth of field location.

[0027] Fine adjustment and fixation of the camera assembly position within a small, handheld device can be difficult to achieve due to space constraints. In some examples, a three-point magnetic kinematic camera mount and alignment assembly 170, shown in FIGS. 8A-8C, is provided to allow adjustment of the camera assembly 112 to center the lens aperture within the field of view (FOV) and permanently fix the camera pointing angle to maintain alignment. Kinematic mounts are typically designed for components that require repeated removal and replacement with a high degree of position and angle repeatability. In the disclosed device, the camera assembly can be aligned once and securely retained for long-term use. The alignment assembly 170 includes three adjustable magnetic screws 802a-c mounted to corresponding internal positions within the main housing, with their heads 804a-c inserted into and magnetically secured in retaining cavities 806a-c of an alignment frame 808. The overall alignment of the camera assembly 112 can be secured using standard alignment features and structures built into the device housing. Fine adjustment of the camera FOV to the aperture of the hub and rotating top can be achieved by adjusting the height of three screws and changing the camera's pointing angle. FIG. 8A shows the camera assembly 112 within the alignment frame 808 of the camera mount assembly 170 and the three screws 802a-c used to angularly align the camera assembly 112 relative to the device housing. FIG. 8B shows a configuration in which the camera mount 170 includes three magnets 810a-c arranged in a triangle (shown in FIG. 8C) around the central axis of the camera within the frame 808, with each magnet 810a-c located at the bottom of a cavity 806a-c. When in place, the screws 802a-c magnetically attach to the magnets 810a-c, and the angular position of the camera 112 is set by the depth of the screws 802a-c. As shown in FIG. 8C, adjusting screws 802a-c changes the pointing angle of camera assembly 112, adjusting screw 802a changes the y rotation, and / or adjusting screws 802b-c along one edge of frame 808 changes the x rotation.During such alignment, the screws 802a-c are adjusted to change the pointing angle so that the center of the FOV coincides with the center of the hub and rotating aperture. In this configuration, no translation is required, since the initial alignment based on the main housing mechanism is sufficient and only fine adjustments are required. In another variation, adjustment of all three screws 802a-c achieves translation along the Z axis. This allows for improved depth of field placement along the Z axis, improving image focus and adjusting the range of the FOV at a given image resolution.

[0028] 19A-19D illustrate another embodiment of a fingerprint capture device 1900, further comprising an optional optically transparent window structure or cover 1902 along the optical path or centerline 500 of the camera assembly 112. Other components of the device 1900 may otherwise be provided and configured similarly to the device 100 of FIGS. 1A-1G, such as the camera assembly 112, actuator 108, wired communication link or cable 110, lens, optical PCB 116, diffuser, camera aperture, aperture support 154, and kinematic camera mount and alignment assembly 170, as previously described.

[0029] As shown in FIGS. 19B and 19C , the optics cover 1902 can be attached to the rotating hub 1912 via a recess 1906. However, in other embodiments, the cover can be attached to the main housing via an annular or circumferential recess in the housing rather than the rotating hub. The recess 1906 can be located on an annular or circumferential flange or support 1908 of the hub 1912, positioning the cover 1902 higher for easier cleaning. As shown in FIG. 19B , the recess 1906 or support 1908 need not have the same angular orientation as the plane of rotation of the hub 1912; for example, as shown in FIG. 19B , the cover 1902 can be positioned partially above and / or below the plane of rotation of the hub 1912. This difference can help reduce reflection artifacts from light sources and / or ambient light during use. The cover 1902 can also help protect the camera assembly 112 from dust and other contaminants, helping to maintain long-term image quality. The cover 1902 may comprise, for example, a polymeric material such as polycarbonate or glass. The cover 1902 may be adhered to the recess 1906 or may form a mechanical interfit with the recess 1906. A rubber or other polymer seal may be provided between the cover 1902 and the recess 1906 to improve sealing and / or retention of the cover 1902 to the housings 1904a / b.

[0030] The cover 1902 may be configured with light filtering properties for various wavelength ranges and / or polarities. The cover 1902 may include one or more coatings, such as water- and / or oil-repellent coatings, on its exterior and / or interior surfaces to render the cover water- and / or fingerprint-resistant, scratch-resistant, anti-reflective, and minimize flare and / or ghosting. The cover 1902 may comprise a generally planar material, although in other variations, it may have recessed and / or protruding portions to provide magnification and / or other lens properties. The lens properties may complement or replace any lenses provided in the camera assembly 112. In the embodiment shown in FIGS. 19A-19D, the cover 1902 may comprise a planar material with a center or average thickness of 8 mm using standard glass. In other variations, based on the type of material and its strength, the cover 1902 may have a center or average thickness ranging from 1 mm to 10 mm, 1 mm to 8 mm, or 2 mm to 6 mm. The cover may have a diameter of 30 mm, or a diameter in the range of 5 mm to 50 mm, 10 mm to 40 mm, or 25 mm to 35 mm. The cover surface area is 700 mm 2 In other variations, the surface area may be 700 mm 2 ~900mm 2 , 600mm 2 ~800mm 2 , or 650mm 2 ~750mm 2 The range may be.

[0031] 19A-18D, the cover 1902 may be oriented at an angle of 11 degrees from the optical centerline 500 of the camera assembly 112. In other variations, the cover orientation angle may range from 0 to 45 degrees, 5 to 30 degrees, or 10 to 15 degrees from the optical centerline 500 of the camera assembly 112. The cover orientation angle relative to the plane of the rotation hub 1912 may be -30 degrees, but in other variations may range from -45 to +0 degrees, -40 to -15 degrees, -35 to -25 degrees, -30 to +5 degrees, or -15 to +0 degrees, for example.

[0032] Another optional feature of the fingerprint capture device 1900 is that the rotating hub 1912 may lack the central dome 166 of the rotating hub 122 shown in FIG. 1J , and therefore the central magnet 144. Alternatively, the rotating hub 1912 of the device 1900 of FIGS. 19A-19D may utilize peripheral magnets (not shown in FIGS. 19A-19D but otherwise configured similarly to those of FIGS. 1A-4L ) on the rotating hub 1912 and rotating top 1914. The rotating hub 1912 lacks a central dome, but may include an annular peripheral flange 1916 on which the rotating top 1914 rests, and an inwardly protruding flange 1918 that is received in an internal cavity of the rotating top 1914. As shown, the inwardly protruding flange 1918 may include a variable or non-uniform protruding height as a result of the orientation angle of the cover 1902. Because the rotating hub 1912 lacks a central dome, the rotating top need not have a central dome-like structure 1922, but may instead include, for example, a flat-ended cylindrical, frusto-conical, or polygonal cross-sectional shape.

[0033] The magnetic attachment allows for easy removal of the camera assembly and easy replacement to adjust the three screws 802a-c and check alignment. Once aligned, the magnetic attraction between the magnets 810a-c of the camera mount 170 and the base screws 802a-c maintains camera alignment over time without the need to secure the camera assembly 112 in a separate manner. This magnetic mount 170 allows the camera assembly 112 to be reproducibly removed for maintenance and reinserted without additional alignment.

[0034] Kinematic fine adjustments are useful for properly aligning the rotating top with the camera field of view, which facilitates the top, which is fixed to the hub of the main housing, having the center of the field of view in place and properly aligned with the aperture.

[0035] Accurate alignment of the camera relative to the aperture facilitates proper detection of which aperture is selected by the user and positioned within the FOV, reducing image processing requirements and correcting for imaging variations by providing physically repeatable alignment. To reduce complexity, the rotating top may not have a position sensor to detect which aperture is positioned, and the camera can be used to detect which aperture is positioned in real time. In some variations, image processing can be used to detect the aperture within the camera FOV and used to identify which aperture is positioned, and dimensions and other image characteristics can be used to normalize or calibrate the camera assembly, images, from image to image and / or subject to subject. Different landmarks or landmark locations can be provided on the interior surface of the rotating top to indicate which aperture is selected, facilitating identification of apertures positioned within the camera FOV. These landmarks can also be used to normalize or calibrate the camera assembly, images, from image to image and / or subject to subject. In some variations, a single white dot is positioned at a unique spot for each aperture, which can be easily and quickly identified using image analysis. Returning to the schematic diagram of FIG. 9A, the locations to the left of dots 906a-h are one for each aperture 1-7. In this exemplary embodiment, dots 906a-h are all aligned in different vertical locations, which can simplify detection and also help confirm the alignment of corresponding apertures 1-7. In the current configuration, there are eight unique apertures, including one for the closed position. More (or fewer) apertures and dots can be used to take advantage of different regions of the camera FOV.

[0036] FIGS. 10A-10C show an example of a rotating top 1000a-c, where each aperture 1002a-c or closed position has a hole or cavity 1004a-c located at a unique location on the rotating top 1000a-c, such that within the field of view from which the images 1006a-c of FIGS. 10D-10F are taken, a corresponding dot 1008a-c appears along the vertical edge 1010a-c (or elsewhere) of the corresponding image 1006a-c. In this particular example, the holes 1004a-c are filled with white silicone, creating optically detectable white "dots." Other methods could be used, such as painting dots onto a surface, 3D printing the top in multiple colors, or placing physical pins to create the pattern to be detected. Images of the current configuration are shown in FIGS. 10D-10F for three different apertures 1012a-c. An image processing algorithm is used to detect the dots, and they are active within the dotted regions 1014a-c of images 1006a-c, so that detection occurs only when the magnets are engaged and the top is in place. FIG. 11A shows dot detection regions 1100a-e for selected apertures of the rotating top 104a shown in FIGS. 4A-4D. Each of the five vertical images 1100a-e shows a dot 1102a-e detected by the image processing algorithm for each aperture 106a-e and the closed position, indicated by placing a detection box 1104a-e around it. The position along the vertical axis of the images 1100a-e determines which aperture is selected. Black horizontal lines 1106a-h indicate the expected potential locations of the dots for detection. The rightmost image 1100f shows all of the dots 1102a-e and boxes 1104a-e of the top superimposed on a single image, showing that they are separated and distinguishable from one another. Figure 11B shows image data for top 104b shown in Figures 4E-4H, which has different combinations of apertures 106e-h and corresponding dot locations, resulting in images 1100f-j with dots and boxes 1102a / c / f / i / j, 1102b / c / f / i / j.In this particular embodiment, the smaller apertures on top 104b are the same size as the largest apertures on top 104a, and therefore share the same dot locations, as well as both of their closed positions. Image 1100k shows all of the dots and boxes 1102a / c / f / i / j, 1104b / c / f / i / j, respectively. Figure 11C shows all dots and detection positions at eight positions for these sets of tops 104a, 104b, including three unique apertures on the smaller top 104a corresponding to dot 1102e at location 1106c, dot 1102d at location 1106d, and dot 1102b at location 1106f, three unique apertures on the larger top 104b corresponding to dot 1102f at location 1106h, dot 1102i at location 1106b, and dot 1102j at location 1106a, an identical aperture 1102a at location 1106g (which is the largest aperture on top 104a and the smallest aperture on top 104b), and a closed position on each top 104a, 104b with the same dot 1102c at location 1106e. In use, a user can place either top 104a, 104b on the device 100 and the apertures 106a-h will detect when in place. The dot locations for the closed position of each different top can be the same or different, so that the top placed on the device can be detected even in the closed position.

[0037] Aside from identifying the rotational position and top aperture, the optical detection of the dot is used in a number of ways to assist the user in collecting fingerprints. One way dot detection is used is to signal that the device is ready for collection. When a dot is detected in the search box, the software control system enables the ability to press a trigger on the device or capture an image via software, thus minimizing the collection of erroneous images if the aperture is not properly placed in place.

[0038] Another aspect of identifying an aperture in place is the ability to crop the resulting image using a binary mask specifically designed for that particular aperture. This significantly reduces the computational power required to apply compared to alternative image analysis and correction algorithms. Using a specific aperture mask during acquisition speeds up processing by removing background other than the finger and reducing the pixel count of the image. If the dot is accurately detected in the correct location, the position of the binary mask is fixed. If necessary, if the aperture is slightly misaligned, the dot's coordinates can be detected and the mask adjusted translationally and / or proportionally. An example of this is shown in FIGS. 16A-16D. FIG. 16A shows an original image 1600 of a finger 1602 placed within an aperture 1604, including a landmark dot 1606. FIG. 16B shows the binary mask 1608 for that aperture 1604 used. FIG. 16C shows a resulting image 1610 of the finger 1602 after applying the mask 1608 to the original image 1600 of FIG. 16A.

[0039] Another optional feature of identifying which aperture is in place is to facilitate a consistent magnification or "zoom" to maximum size for that aperture. This can be useful when scanning the smallest newborn fingers, where features and alignment need to be visually confirmed on a computer screen. The predetermined fixed area on the display corresponding to each aperture and the resulting collected image can be presented to the user at a standardized size, zoomed into the finger based on the detected aperture. FIG. 16D shows a zoomed-in or enlarged image 1612 of the finger 1602 as it appears to the user on the display.

[0040] Identification of the aperture size selected by the user facilitates the potential determination of finger size. If finger size is determined early, image processing can adjust the age adjustment calculation for faster results.

[0041] Identifying that the aperture is not in an expected position allows the software to reduce computational effort by not performing unnecessary functions if one or more expected imaging characteristics are not present or otherwise detected, e.g., an auto-exposure function is performed only if the aperture is in place.

[0042] Other markings can be used to indicate the size and current position of the apertures. For example, Figures 12A-12C show a set of images 1200a-c of apertures 1202a-c, with vertical lines 1204a-c, 1206a-c printed or formed on the underside of the rotating top, which can be optically detected and used to determine which apertures are within the camera's FOV. The vertical lines 1204a-c, 1206a-c can be more easily detected through image processing, and the distance between the vertical lines 1204a-c, 1206a-c can be used to determine the size of the aperture or the corresponding aperture 1202a-c. Other top configurations not based on a rotating design can also be used to adjust the size of the apertures. A movable aperture can be used, where one side of the aperture is fixed and the other side can be moved to adjust the size of the opening. In this case, the lines and / or dots can be optically detected, allowing the size of the aperture to be determined in real time. Examples of various movable apertures are described in US Patent Nos. 10,496,870 and 11,003,883. A separate barcode or QR code can be used for each aperture and can be detected using a camera.

[0043] FIG. 18 provides an overview of the system's operation and software architecture 1800. In particular, this flowchart illustrates a process 1800 for the acquisition of a single image of a finger, repeated for each finger as requested by the operator. During acquisition, the raw image is streamed (1802), and upon detection of an aperture dot 1804, other processes are initiated. Detection of the dot initiates other processes, such as exposure control (1806) and trigger activation (1808). Once a trigger for acquisition is detected (1810), an image is captured (1812), processed to a desired image resolution in pixels per inch (PPI), processed for quality, and displayed to the user. This process includes applying a mask (1814), contrast enhancement (1816), and pixel / ridge analysis (1818). Once the desired PPI level is set (1820), the image is converted to the desired PPI (1822). Fingerprint analysis (1824) is performed on the transformed image, and various characteristics and scores (1826) (e.g., binary image quality score, number of minutiae, etc.) are generated and displayed with the processed and / or original image (1828). A second trigger press (1830) restarts the process.

[0044] For infants and young children, the biometric observer must physically place and align the finger on the device without assistance from the subject. Due to the need to assist the subject, it is useful for the device to be operable with one hand, freeing the other hand for placement and proper alignment of the subject's finger on the device.

[0045] The device may also be symmetrically designed so that it can be operated equally by right-handed and left-handed users. Special designs may facilitate one-handed operation, with the external mechanisms of the device being specifically molded for one-handed or opposite-handed use. Having specific right-handed and left-handed devices may be more comfortable for users.

[0046] One feature of this device is its ability to capture fingerprint images across a wide range of ages and finger sizes. Industry-standard fingerprint capture devices are not used to collect images of children for several reasons: 1) the optical resolution of standard fingerprint capture devices is not fine enough to detect smaller ridges, and 2) children grow over time, causing fingerprint images to become inconsistent and change over time.

[0047] The ridges in children's fingerprints are extremely small, and standard fingerprint capture devices have an image resolution of 500 pixels per inch (PPI), with some newer models increasing this to 1000 PPI, which is sufficient to image the ridges in adult fingerprints.

[0048] Whether the images of adults were collected at 500 PPI or 1000 PPI, standard fingerprint processing algorithms require the images to have a resolution of 500 PPI, because all image processing algorithms are trained on images at that resolution, and because the majority of fingerprints in fingerprint databases are scanned and stored at that resolution.

[0049] For adults, the distance between fingerprint ridges on adult fingers is approximately 400–500 microns, so a 500 PPI imager would have a sampling distance of 50 microns, placing 8–10 pixels between adjacent ridges. Children, on the other hand, have the same number of ridges. Children's fingerprints are fully formed, but the ridges are closer together because they are distributed across smaller fingers, which changes with age. The smallest newborns may have ridges spaced only 125 microns apart, and a 500 PPI imager cannot adequately distinguish between adjacent ridges with only 2–4 pixel sampling. Furthermore, image processing algorithms used in standard fingerprint capture devices assume 8–10 pixels between ridges, so image processing algorithms that detect and enhance ridge contrast will not function and will incorrectly evaluate the child's image. Furthermore, as children grow and the location of fingerprint minutiae changes over time, the newborn's fingerprints will change sufficiently to no longer match those of older children.

[0050] These challenges are addressed by designing devices with both high-resolution imaging devices and image processing algorithms that compensate for the changing size of a growing child. To have 10 pixels between an infant's ridges, the image size of each pixel in the imaging plane needs to be approximately 12.5 microns, which corresponds to an image resolution of approximately 2000 PPI. Current devices exceed 3000 PPI to ensure that the small details of a child's fingers can be resolved.

[0051] Because finger age and size vary from person to person and over time, the image processing performed here normalizes all images to a constant number of pixels between each fingerprint ridge. An image processing algorithm is used to estimate the average distance between ridges for each finger, and the image is resampled to place 8-10 pixels between ridges, producing an "adult-equivalent" image of 500 PPI that can be evaluated by standard fingerprint biometric image enhancement systems. All different finger sizes are resampled to have the same number of pixels between ridges, regardless of the finger's original size.

[0052] For example, Figures 13A-13F show images of subjects' fingers of various ages and sizes. Figure 13A is an infant's finger with approximately 20 pixels between each ridge of the fingerprint. Figure 13B is an infant's finger with approximately 24 pixels between each ridge of the fingerprint. Figures 13C-13E have 28, 32, and 36 pixels between each ridge. Figure 13F is an adult's finger with 40 pixels between each ridge.

[0053] Size differences can be addressed by generating fingerprint images at a higher resolution, downsampling them to a standard 500 PPI equivalent, and normalizing the fingerprints to a single size. Figure 14A shows an image of an infant's finger, Figure 14B shows an image of a one-year-old's finger, and Figure 14C shows an image of an adult's finger, each shown at their appropriate relative sizes. To evaluate images with widely varying sizes, the fingerprints are normalized to a standard 500 PPI image, with 8-10 pixels between each fingerprint ridge. The results of this type of process are shown in Figures 14D, 14E, and 14F for processed images of a newborn, a one-year-old, and an adult, respectively. In Figures 14D-14F, all finger sizes have been normalized to a consistent resolution. After normalization, fingers of various sizes can be resampled, and the resulting fingerprint minutiae maps can be the same size regardless of starting age.

[0054] Minutiae location maps expand as a child grows, and researchers have developed mathematical models that can be used to correct for age (and size) differences as a child grows. If an early fingerprint is taken when a child is one year old and a second fingerprint is taken when the child is six years old, these models can be used to extrapolate or "grow" the early fingerprint minutiae template five years to attempt to match it with a later image. Growth factors are often the average of data taken for a group of children. This averaging can be problematic in that children do not grow at the same rate or are not the same size at any age.

[0055] Some exemplary image processing methods directly measure ridge distance or estimate ridge density in real time for each child's individual finger. Some existing algorithms may use an average distance based on the child's age or age group to correct the image. However, in some fingerprinting embodiments herein, the size of a child's specific finger is measured and resampled to a consistent 500 PPI "adult equivalent." This is done for the same child or person, regardless of image, and each is given the same nominal pixel / ridge value of 8-10 pixels per ridge, based on image characteristics rather than the child's reported age, as shown in Figure 11. This method provides a known pixel / ridge value for all finger images, regardless of the child's age or size, eliminating the problem associated with assuming a child is average-sized. This may be performed per image, or calculated once per subject, and reapplied to each subsequent image for that subject, repeating the PPI normalization process.

[0056] In a standard contact fingerprint capture device, a finger is placed and rolled on a platen to collect data across the entire surface of the finger, often referred to as nail-to-nail (N2N). While this may not be possible or easy to accomplish with a single camera in a contactless device, some variations allow multiple images of the finger to be captured from multiple angles by instructing the subject and / or user to rotate the finger appropriately. The multiple images can then be stitched together to create an N2N composite image. This can be accomplished using a standard aperture or an N2N custom aperture, which helps the user position and rotate the finger to collect image data.

[0057] To assist the user in collecting the highest quality images, the device can provide feedback during collection, guiding the user regarding various image characteristics and the appropriateness of the captured image. One exemplary method is to utilize one or more core detection algorithms that mark the image to indicate to the user where the fingerprint core is located. With contactless imaging, finger curvature is a variable that potentially makes recording and matching difficult or challenging. Some data indicates that matching performance can be beneficial when the finger image and the authenticating finger image have closely aligned cores. One way to ensure this is to instruct the user to always have images collected with the core centered and / or to have multiple images with the core collected at additional, clearly defined locations. In some system variations, the standard collection procedure guides the user to collect multiple locations by tracking the core's location and provides feedback indicating when the required images have been collected. This can be achieved by providing a fiducial on the image overlay where the user needs to align the core on the subject's finger. Once an image satisfying the required core location is collected, the fiducial mark changes to indicate that a location image has been collected and the user can move on to the next location. Figure 17A shows an original image of a finger with automatic detection of a core 1700 indicated by a box 1702. Figure 17B shows a group of five potential locations 1704 that are suggested to the user for positioning the core during image acquisition.

[0058] Another optional quality feedback process that can be implemented includes detecting the pressure the finger is exerting on the device. When the user or subject places their finger on the aperture, some image acquisition processes may prefer that the finger be in light contact with the aperture. Pressing the finger too hard against the device tends to push the finger through the aperture, causing skin stretching. As the skin stretches, ridges and valleys become less distinct and the contrast between them decreases. This makes analyzing the image for ridge terminations and branches (i.e., feature points) more difficult. The image processing algorithm can provide feedback on pressure in several ways. One is through image processing that detects an increase in blood pooling in the center of the finger based on changes in pixel color or relative color or pixel light level or relative light level. As finger pressure increases, blood flow becomes restricted, resulting in a blood pool in the center of the finger surrounded by a decrease in blood at the finger / aperture contact point. This can be detected optically by evaluating the contrast of the image across the finger. Another method is available that uses spectral analysis to directly detect blood, similar to that used in pulse oximeters, but across the finger image to detect this pressure effect. By observing the contrast of the image in real time, too much pressure can be inferred. If the contrast (between the ridges and valleys of the fingerprint) decreases significantly, feedback can be provided suggesting the user to reduce the pressure applied to the device.

[0059] Some variations described herein relate to computer storage products with a non-transitory computer-readable medium (also called a non-transitory processor-readable medium) having instructions or computer code for performing various computer-implemented operations. The computer-readable medium (or processor-readable medium) is non-transitory in the sense that it does not include a transient propagating signal itself (e.g., a propagating electromagnetic wave that carries information over a transmission medium such as space or a cable). The medium and computer code (also called code or algorithm) may be designed and constructed for a specific purpose. Examples of non-transitory computer-readable media include, but are not limited to, magnetic storage media such as hard disks, floppy disks, magnetic tape, etc., optical storage media such as compact disks / digital video disks (CD / DVD), compact disk read-only memories (CD-ROM), holographic devices, magneto-optical storage media such as optical disks, solid-state storage devices such as solid-state drives (SSD), solid-state hybrid drives (SSHD), carrier wave signal processing modules, and hardware devices specially configured to store and execute program code, such as application specific integrated circuits (ASICs), programmable logic devices (PLDs), read-only memory (ROM), random access memory (RAM) devices, etc. Another variation described herein relates to computer program products that include, for example, the instructions and / or computer code disclosed herein.

[0060] The systems, devices, and / or methods described herein can be implemented by software (executed on hardware), hardware, or a combination thereof. Hardware modules may include, for example, general-purpose processors (or microprocessors or microcontrollers), field-programmable gate arrays (FPGAs), and / or application-specific integrated circuits (ASICs). Software modules (executed on hardware) can be expressed in various software languages ​​(e.g., computer code), including C, C++, JAVA®, Python, Ruby, VISUAL BASIC®, and / or other object-oriented, procedural, or other programming languages ​​and development tools. Examples of computer code include, but are not limited to, microcode or microinstructions, machine instructions generated by a compiler, code used to generate web services, and files containing high-level instructions executed by a computer using an interpreter. Additional examples of computer code include, but are not limited to, control signals, encryption code, and compression code.

[0061] In some variations, the systems and methods may communicate with another computing device (not shown), for example, via one or more networks, each of which may be any type of network (e.g., wired network, wireless network). A wireless network may refer to any type of digital network that is not connected by any type of cable. Examples of wireless communications in a wireless network include, but are not limited to, cellular, radio, satellite, microwave communications, etc. However, a wireless network may connect to a wired network to interface with the Internet, other carrier voice and data networks, business networks, and personal networks. Wired networks are typically transmitted via copper twisted pair, coaxial cable, and / or fiber optic cable. There are many different types of wired networks, including wide area networks (WANs), metropolitan area networks (MANs), local area networks (LANs), Internet area networks (IANs), campus area networks (CANs), wireless personal area networks (PANs) (e.g., Bluetooth, Bluetooth Low Energy), global area networks (GANs) like the Internet, and virtual private networks (VPNs). Hereinafter, a network refers to any combination of wireless, wired, public and private data networks that are typically interconnected via the Internet to provide an integrated network and information access system.

[0062] Cellular communications may encompass technologies such as, for example, GSM, PCS, CDMA or GPRS, W-CDMA, EDGE or CDMA2000, LTE, WiMAX, 5G network standards, etc. Some wireless network deployments combine networks from multiple cellular networks or use a mix of cellular, Wi-Fi, and satellite communications. In some variations, the systems, devices, and methods described herein may include radio frequency receivers, transmitters, and / or optical (e.g., infrared) receivers and transmitters for communicating with one or more devices and / or networks.

[0063] While the various embodiments above have been specifically shown and described with reference to such embodiments, those skilled in the art will recognize that various changes in form and detail may be made therein without departing from the scope of the embodiments. In all of the above-described embodiments, the method steps need not be performed sequentially.

Claims

1. A fingerprint input system, comprising: - A main housing is provided, an elongated handle including a longitudinal axis; a rotating hub integrally formed with an elongated handle, the hub comprising: an upper convex surface; an imaging aperture in the upper convex surface; a circular flange surrounding the upper convex surface, the circular flange having an upper undulated surface; The fingerprint input system also a plurality of peripheral hub magnets equally spaced around the circular flange, each hub magnet being located the same hub radial distance from the center of the rotating hub; -An actuator installed in front of the elongated handle; an imaging assembly located inside the elongated handle and including an imaging axis; a removable rotating aperture top configured to form a rotation interface with a rotation hub, the selector comprising: a concave lower surface configured to form a complementary rotational interface with an upper convex surface of the hub; a plurality of finger-receiving apertures, each aperture being a different size and including a chamfered peripheral edge disposed in the aperture plane; a plurality of flanges configured to surround the concave lower surface and extend radially outward beyond the circular flange of the rotation hub, the plurality of flanges being radially offset from the plurality of finger-receiving apertures, each of the plurality of flanges including a wavy surface complementary to a portion of the wavy surface of the circular flange of the rotation hub; a plurality of peripheral top magnets equally spaced around the plurality of flanges, each of the plurality of top magnets being located at the same top radial distance from the center of the top; an optically transparent cover between the imaging assembly and the removable rotating top.

2. The system of claim 1 , wherein the optically transparent cover is oriented at an offset angle of between ** degrees and ** degrees relative to the imaging axis.

3. The system of claim 2 , wherein the optically transparent cover is oriented at an offset angle from the plane of the circular flange of the rotating hub.

4. The rotating hub further comprises a central hub magnet disposed at the center of the rotating hub; a central top magnet located at the center of the removable rotating aperture top; The system of claim 2 , wherein a center of the removable rotating aperture top and a center of the rotating hub define an axis of rotation.

5. A fingerprint input system, comprising: - A main housing is provided, an elongated handle including a longitudinal axis; a rotating hub integrally formed with an elongated handle, the hub comprising: a hub interface surface; Center and an imaging aperture on the surface of the hub; a first plurality of alignment structures equally spaced about the rotating hub, each of the plurality of alignment structures being located at the same hub radial distance from the center of the rotating hub; The fingerprint input system also - an actuator located on an elongated handle; an imaging assembly located inside the elongated handle and including an imaging axis; a removable rotating aperture top configured to form a rotation interface with a rotation hub, the selector comprising: a top interface surface including a center configured to form a complementary rotational interface with an upper convex surface of the hub, the top interface surface including a center, the center of the top and the center of the hub defining an axis of rotation; a plurality of finger-receiving apertures, each aperture being a different size and including a chamfered peripheral edge disposed in the aperture plane; a plurality of flanges surrounding the top interface surface and configured to extend radially outward beyond the rotation hub, the plurality of flanges being radially offset from the plurality of finger-receiving apertures; A fingerprint input system comprising: a first plurality of alignment structures mounted on a rotating hub; and a second plurality of alignment structures arranged in a complementary configuration.

6. The system of claim 5 , wherein the device further comprises an adjustable camera alignment mount.

7. The system of claim 6 , wherein the adjustable camera alignment mount comprises a frame and three adjustment screws.

8. the frame comprises a polygonal shape with four sides and four corners; a first of the three adjustment screws is provided at the center of one of the four sides; The system of claim 7 , wherein the second and third adjustment screws are located at two of the four corners furthest from the first screw.

9. The system of claim 7 , wherein the adjustable alignment mount is releasably coupleable to the imaging assembly via a mount magnet attached to the frame.

10. The system of claim 7 , wherein the imaging assembly is mounted within a frame opening of the frame.

11. The three magnets are embedded in the frame, The system of claim 7 , wherein the three adjustment screws are magnetically attachable to the magnet.

12. The system of claim 11 , wherein the three adjustment screws are mounted to the main housing.

13. The system of claim 5 , further comprising a first heat sink thermally coupled to the imaging assembly.

14. The system of claim 5 further comprising a lighting assembly including a plurality of light sources within a main housing.

15. The system of claim 14 , wherein the lighting assembly comprises a circular base.

16. The system of claim 14 , further comprising a light diffuser above the lighting assembly.

17. The system of claim 14 , further comprising an illumination heat sink thermally coupled to a bottom surface of the illumination assembly.

18. The system of claim 6 , further comprising a camera support between the imaging assembly and the adjustable camera alignment mount.

19. The system of claim 6 , wherein the first plurality of alignment structures and the second plurality of alignment structures each comprise a magnet.

20. a third plurality of alignment structures mounted on the rotating hub; 20. The system of claim 19, further comprising: a fourth plurality of alignment structures complementary to the third plurality of alignment structures and mounted on the removable rotating aperture top.

21. the third plurality of alignment structures comprises a plurality of alternating wavy or sloped surfaces; 21. The system of claim 20, wherein the fourth plurality of alignment structures comprises a plurality of alternating wavy or angled surfaces complementary to the third plurality of alignment structures.

22. 22. The system of claim 21, wherein the third plurality of alignment structures are located along an upper peripheral circular surface of the rotating hub.

23. 23. The system of claim 21 or 22, wherein the fourth plurality of alignment structures are located on the underside of the plurality of flanges.

24. The system of claim 5 further comprising an elongated planar measurement tool including a plurality of different apertures arranged successively by size along the tool.

25. 25. The system of claim 24, wherein the measurement tool further comprises a plurality of sequence markings corresponding to a plurality of different apertures.

Images