Abstract: In one embodiment, the system and device of the present invention extracts unique numerical information from a fingerprint. A fingerprint is first scanned and the scanned image is enhanced. The blurred area of the image is restored and the enhanced image is binarized. The binarized image is then thinned. A core point in the image is detected and minutiae within a given radius from the core point are detected. A number is then extracted from the image by computing relation of minutiae to the core point.

Abstract: A given point of interest in an image is defined by two properties, a local attribute, such as color, and a neighborhood function that describes a similarity pattern. The color value is not influenced by nearby background regions of the image, and functions as a descriptor for each location. The neighborhood function distinguishes locations of similar color from one another, by capturing patterns of change in the local color. The neighborhood function measures the similarity between the local color and colors at nearby points, and reduces the measured similarity values that lie beyond contrast boundaries. Through the computation of such a transform for points of interest in an image, corresponding points in other images can be readily identified.

Abstract: A method for identifying fingerprints includes the steps of acquiring a primary image and a secondary image; determining notable points in the primary image; comparing with one another the primary image and the secondary image in order to identify the correspondences between the primary image and the secondary image; and validating the possible correspondences. The comparison between the primary image and the secondary image is based on comparison of the regions which surround the notable points on the primary image, with all the points of the secondary image, through a flash cell array, such as to obtain lists of points in the secondary image which are probably associated with the notable points.

Abstract: An original image is held in the image holder 11, and displayed on the image display 12 to be viewed by the operator. The operator inputs the angle of rotation and ratio of compression of an focal point of the original image for observing ridges more clearly. A perspective transforming unit 14 generates a result image according to corresponding perspective transformation (i.e., affine transformations), and a perspective transformed image display 15 displays the result image to the user. The operator does operations of manual plotting and manual tracing with reference to the result image. The result of the operations is inputted to and recorded in the manual input unit 16, and transformed in a feature data transforming unit 17 to feature data.

Abstract: A method of identifying fingerprints, the method including the steps of: acquiring a test image formed by a number of test points characterized by different grey levels defining a test surface; determining significant points in the test image; and verifying the similarity between regions surrounding the significant points and corresponding regions of a reference image whose points present different grey levels defining a reference surface. The similarity between the regions is verified by computing the integral norm of portions of the test and reference surfaces; and the integral norm is computed using flash cells programmed with a threshold value correlated to the value of the grey levels in the reference region, by biasing the flash cells with a voltage value correlated to the grey level in the test region, and measuring the charge flowing through the flash cells.

Abstract: The invention is a system and method for determining alignment parameters (rotation angle and translation vector) between two images of scene based on the attributes of segments associated with a pair of corresponding points, each point extracted from each of the images.

Abstract: The present invention can achieve the reliability and simplicity in registering a fingerprint by indicating the quality of a fingerprint image by the number of pseudo minutiae, improve the security of an entrance/exit control system to register a fingerprint, detect the direction of ridge lines of a fingerprint accurately as much as possible, improve the security in checking a fingerprint remarkably, collect renewed registered fingerprint data by a host device and hold the registered fingerprint data of each gate as the latest fingerprint data, improve the operability by enabling to use identification numbers having the less number of digits, and register a fingerprint having a high match rate by automatically applying spatial filtering in re-registering only.

Abstract: The present invention can achieve the reliability and simplicity in registering a fingerprint by indicating the quality of a fingerprint image by the number of pseudo minutiae, improve the security of an entrance/exit control system to register a fingerprint, detect the direction of ridge lines of a fingerprint accurately as much as possible, improve the security in checking a fingerprint remarkably, collect renewed registered fingerprint data by a host device and hold the registered fingerprint data of each gate as the latest fingerprint data, improve the operability by enabling to use identification numbers having the less number of digits, and register a fingerprint having a high match rate by automatically applying spatial filtering in re-registering only.

Abstract: A method and system for performing automated biological identification. The system including a preprocessing module with a histogram transform for locally and globally enhancing biological data such as fingerprints. An enhancement module with a fast smoothing and enhancement function. A feature extraction module with a fingerprint oriented thinning function. A matching module with a resolution-enhanced Hough transform function for fingerprint registration and matching score function.

Abstract: The present invention provides a fingerprint sensor chip formed on a dielectric layer of a semiconductor wafer. The fingerprint sensor chip comprises a plurality of rectangular sensor areas arranged in a matrix format which are surrounded by conductors, a second dielectric layer covering the sensor areas and the conductors wherein the surface of the second dielectric layer positioned above each of the sensor areas is formed as a protruding rectangular platform with a shallow trench around the platform, a rectangular metal plate positioned on top of each of the rectangular platforms which is used as a sensor plate of the fingerprint sensor chip, and a protective layer positioned on the surface of the semiconductor wafer to cover and protect the underlying circuitry.

Abstract: The invention achieves stabilization of the verification performance and augmentation of the verification performance. The fingerprint data synthesis apparatus includes a fingerprint data extraction section for extracting minutiae from each of a plurality of fingerprint images to produce fingerprint data, a fingerprint data storage section for storing the fingerprint data, a common minutia searching section for investigating a correspondence of the minutiae between the plurality of fingerprint data to search for the same minutiae included commonly in two or more of the plurality of fingerprint data as common minutiae, a fingerprint data synthesis section for selecting one of the common minutiae as a minutia representative of the common minutiae to produce one synthetic fingerprint data, and a validation section for validating the synthetic fingerprint data. The apparatus is applied to production of fingerprint data used in a system which identifies an individual.

Abstract: A fingerprint image cutout processing device for a tenprint card includes a tenprint card image input unit for inputting, on a card basis, image data of a tenprint card in which rolled fingerprints and plain fingerprints of ten fingers of each hand are printed, an image storage unit for storing image data of the tenprint card input by said tenprint card image input unit, cutout information input portion for displaying the tenprint card images and ten cutout frames for specifying a cutout range of a fingerprint image of each finger to be superposed with each other and receiving input of fingerprint cutout information of each finger, and a cutout and edit portion for cutting and editing fingerprint image data of each finger out of the image data of the tenprint card stored in the image storage unit and displaying the edited data based on the input cutout information.

Abstract: A biometric input device, system and method includes a biometric input device having a scanning window surrounded by a ridge for ensuring positive positioning of a biometric sample such as a thumb. The biometric input device includes an optical assembly having a prism with a focusing lens disposed on a side thereof and optionally integrally formed therewith. A biometric comparison method is provided for comparing data from said biometric input device with data from a database using both directional image comparison and clusterized minutia location and direction comparison. A further system is provided for allowing access to computer functions base on the outcome of the comparison method.

Abstract: A computer based image processing system uses an extraction process to include a pressure invariant feature for measuring distances between minutiae. The feature extraction process identifies one or more of the following features of the fingerprint: an orthogonal image contrast, a parallel image contrast, and a feature confidence. A ridge counter process, executing on the computer system, determines the number of ridges (ridge count) running across two given points and further qualifies (invalidates) this count if the confidence value of the pixels in the region adjoining the region is not reliable. The ridge count feature between minutiae is used for determining reliable features when matching fingerprints.

Abstract: Disclosed in a system and method for segmenting foreground pixel from background pixels in a digital image, specifically a fingerprint image. First the image is divided into blocks of optimal size. Then, for a given block, an overall gradient magnitude and a projected gradient magnitude is determined. The overall gradient magnitude is a measure of the amount of intensity variation in the current block. If a large number (or all) of the pixels have a direction that is the same as the overall gradient direction, the projected gradient magnitude will be nearly equal (will be equal) to the overall gradient magnitude. This indicates that the current block is a block in the foreground of the image. A relationship, e.g., a ratio, of the over gradient magnitude to the overall projected gradient magnitude is taken certainty level that the current block is in the foreground or background of the image.

Abstract: The password input apparatus of the present invention comprises: a database for storing feature data of a previously registered master fingerprint and a password of an authorized user in a related manner; a camera for obtaining a fingerprint being inputted from the user's finger; an extractor for extracting feature data of the fingerprint; a controller for reading the password from the database based on the feature data extracted by the extractor; and an interface for outputting the password to another device.

Abstract: A method of identifying fingerprints, the method including the steps of: acquiring a test image formed by a number of test points characterized by different grey levels defining a test surface; determining significant points in the test image; and verifying the similarity between regions surrounding the significant points and corresponding regions of a reference image whose points present different grey levels defining a reference surface. The similarity between the regions is verified by computing the integral norm of portions of the test and reference surfaces; and the integral norm is computed using flash cells programmed with a threshold value correlated to the value of the grey levels in the reference region, by biasing the flash cells with a voltage value correlated to the grey level in the test region, and measuring the charge flowing through the flash cells.

Abstract: A feature point information calculating unit calculates the connection of a feature point extracted by a feature point extracting unit through a ridge. An identifying unit identifies the connection state of the feature point calculated by the feature point information calculating unit.

Abstract: The present invention is a method and apparatus for automatically placing a first unknown image, such as an unknown fingerprint image, into one of a plurality of categories. The invention includes storing in a library a plurality of value series, each of which series is derived from the frequency representation of an image category. The categorization process and apparatus takes the frequency image of a first unknown pattern to create a first frequency image. The frequency image plane of the first (unknown) frequency image is divided into a plurality of frequency image plane regions. Each of the frequency image plane regions may be an angular segment radiating from the origin of the frequency image plane. A region value is assigned to each of the frequency image plane regions based on the total energy in the frequency image in that region. The region values for the first frequency image are combined to generate a first series of region values.

Abstract: The invention relates to a system and methods for verifying a person's identity, and pertains in particular to such a system and methods which utilize comparison of a fingerprint pattern for identification verification. The image of a fingerprint of a person to be identified is provided on an inkless means which when touched by a finger of the person causes immediate development of an image of the fingerprint of the finger in a black and white appearance. This image of a fingerprint is video scanned to produce image data which is digitized to produce a non-minutiae digitized numerical identifier indicative of the fingerprint. A preferred method and system provides a non-minutiae digitized numerical identifier having 24 bytes of fingerprint identification data which is recordable within the magnetic stripe of a credit card personal to a person, or may be recorded within the confines of a portable personnel identification means, or within a smart card, personal to a person.

Abstract: For the better identification of not-enrolled fingerprint images, images of skin lines of two juxtaposed fingers (1, 2) of a hand are recorded. The orientations of the finger longitudinal axes (L1, L2) with respect to the normal direction (N) are determined and by means of a guidance means (13) a rotation or twisting (W1) of the fingers about their longitudinal axis is largely avoided, so that virtually coinciding, defined partial image quantities (B3, B4) of the complete enrolled fingerprint (A) are detected and transferred by evaluation algorithms into a reduced data quantity. This allows a much greater identification reliability with a smaller storage requirement and simpler evaluation algorithms.

Abstract: A system and method for authenticating fingerprints includes a remote site having a scanner for generating fingerprint data and an access mechanism. A local site connects to the remote site via transmission cables and includes a processor for extracting minutia from the fingerprint data. A comparator matches the fingerprint data to historical fingerprint data maintained in a database to verify whether the detected fingerprint data falls within statistical maximum deviations and exceeds statistical minimum deviations to establish the authenticity of the fingerprint.

Abstract: An apparatus, method, and computer program for providing authenticating indicia and verifying the image thereby. One particular embodiment is a biometric application such as a fingerprint-based authentication system. The apparatus includes an image receiver for receiving the original image with true image point, a false image point generator providing false image points, and a transient template generator that selectively combines the true image points and the false image points. The apparatus can also constrain false image points to be non-coinciding plausible impostors of the true image points. The apparatus can include a claimant image receiver, a transient template receiver and a comparator for comparing the claimant image points with the template image points and producing an authentication signal.

Abstract: The invention is a system and method for matching a two dimensional pattern of lines, e.g. a fingerprint, by creating a one dimensional representation of one or more points (e.g., minutiae) on the lines in the patterns to be matched. The one dimensional representations are created by finding a corresponding reference point (minutiae) in each of the patterns and creating an index of other points in each of the respective patterns with respect to the reference point (minutiae). The indexes are adaptively compared taking into account the elastic distortions of the lines.

Abstract: A method and apparatus for annotation of medical imagery to facilitate patient identification, diagnosis, and treatment is characterized by an imaging device for producing a first signal representative of sensed characteristics of the individual and a minutiae generator which receives the first signal and produces a second signal representative of minutiae of the individual, the minutiae corresponding to specific branch points of blood vessels of the individual. A minutiae data generator analyzes the characteristics of minutiae and produces a third signal representative of the characteristics which is stored in a minutiae database for each of the plurality of known individuals and their medical conditions. The minutiae and minutiae data may be used to annotate medical imagery to facilitate subsequent image comparison by providing standardized registration points and time-varying characteristics.

Abstract: A device, and a method for its operation, for verifying a person's identity by comparing in a correlator (18) selected features of a reference fingerprint image, generated in a sensor (10) from the fingerprint of a person of known identity, with a subject fingerprint image taken from a person whose identity is to be verified. In an enrollment procedure, a fingerprint from a person of known identity is analyzed in an enrollment processor (14) to locate multiple reference patches that together are distinctive to that person's fingerprint. The reference patch images are stored, together with their locations in the image, in a reference image storage unit (16). When a subject fingerprint image is later provided, every reference patch is compared with every possible patch of similar size in the subject image, to find a set of candidate match locations in the subject image.

Abstract: A dictionary image renewing method in a fingerprint identification device registers images into a dictionary memory as multiple dictionaries. The method includes extracting images from a plurality of fingerprint images determined as being acceptable identification by mutual identification and using the multiple dictionaries to perform identification processing of entered fingerprint images. This includes successively identifying by comparing entered fingerprint images with the dictionary images registered in the multiple dictionaries, and when identification acceptance results with any one of the multiple dictionaries the one dictionary determined as being identification accepted is renewed to the dictionary image registered in any one of the remaining dictionaries. The remaining multiple dictionaries are renewed to the dictionary image extracted from the entered fingerprint images.

Abstract: A computer implemented method may be used in classifying and identifying finger prints. Dab prints are analyzed according to intersections with fiducial lines. A two-dimensional Hidden Markov Model is then used to correspond states of data based on the intersections.

Abstract: A local information extracting portion 11 extracts a plurality of ridge line candidate images for each of local regions into which an image has been divided. A first ridge line candidate image selecting portion 12 selects a first ridge line candidate image that has high likelihood of a ridge line for each local region. A connectivity evaluating portion 13 evaluates the connectivity of first ridge line candidate images between each local region. A clustering portion 14 clusters local regions corresponding to the evaluated result of the connectivity evaluating portion 13 and generates a local region group. A cluster evaluating portion 15 determines an initial local region group that is a local region group having high likelihood of a ridge line. A ridge line image restoring portion 16 outputs a first ridge line candidate image for each local region that is included in the initial local region group.

Abstract: A computer based image processing system uses an extraction process to include a pressure invariant feature for measuring distances between minutiae. The feature extraction process identifies one or more of the following features of the fingerprint: an orthogonal image contrast, a parallel image contrast, and a feature confidence. A ridge counter process, executing on the computer system, determines the number of ridges (ridge count) running across two given points and further qualifies (invalidates) this count if the confidence value of the pixels in the region adjoining the region is not reliable. The ridge count feature between minutiae is used for determining reliable features when matching fingerprints.

Abstract: Apparatus, and a corresponding method for its use, for gaining access to and operating a vehicle, such as a car (10), by means of at least one fingerprint sensor (16) installed inside the vehicle at a convenient location and, optionally, outside the vehicle (at 14), in or near a door handle (12). Once an authorized user's identify has been verified in a fingerprint matching device (30), various vehicle subsystems are automatically adjusted to the identified user's preferred settings, which are stored in a memory (98). In addition, starting the vehicle engine is enabled if an interior fingerprint sensor has been used, or the vehicle is unlocked if an exterior fingerprint sensor has been used. Vehicle subsystems that are automatically adjusted to the user preferences include seats (38), mirrors (40), steering wheel (42), climate control (44), airbag (52), telephone (46), radio (50) and onboard computer (54), as well as performance control features (48) such as suspension and transmission adjustment.

Abstract: A pattern collation apparatus is designed to identify a registration pattern and a collation pattern as identical patterns or not even with a rotation offset between the registration pattern and the collation pattern. The image data of a registration fingerprint is rotated through m.multidot.a degrees, and two-dimensional discrete Fourier transform is performed for the resultant image data to obtain registration Fourier image data. The registration Fourier image data with m=-90 to +90 are filed as registration Fourier image data. In collation processing, registration Fourier image data are read out from the registration Fourier image data in units of patterns, and each registration Fourier image data is synthesized with the collation Fourier image data, thereby performing collation between the registration fingerprint and the collation fingerprint.

Abstract: The invention provides a fingerprint characteristic extraction apparatus wherein classification and preselection processing with an augmented degree of accuracy can be achieved without significantly increasing the processing time. The apparatus uses, in addition to characteristic amounts used in ordinary preselection processing, another characteristic amount obtained from a fingerprint image for the preselection processing. The apparatus includes a ridge extraction section for extracting ridges from an inputted fingerprint image, a singular point detection section for detecting singular points from the ridges, a main pattern discrimination section for discriminating a pattern of the inputted fingerprint image, and a singular point characteristic calculation section for detecting characteristic amounts between the singular points.

Abstract: A biometric time and attendance device for scanning an epidermal portion of a human body, generating an epidermal topographical pattern and transmitting the epidermal topographical pattern to a host computer for determining access privileges and for updating epidermal topographical database.

Abstract: A computer based image processing system uses an extraction process to extract one or more features from a target fingerprint image. The feature extraction process identifies one or more of the following features of the fingerprint: orthogonal image contrast, parallel image contrast, feature confidence, distance between two minutia, neighbor information, angle-distance between two minutia, angle-distance neighbor information, minutiae density, ridge length, ridge density, and wiggle factor. A pruner process, executing on the computer system, determines if one or more of the features meet any one or more of a set of pruning criteria, and that deletes the minutiae if the pruning criteria is met. The pruning process is based on (i) locations and image contrast, (ii) the distances, orientations of minutiae and (iii) spatial distributions of minutiae and ridges of the fingerprint. The minutiae that remain after the pruning can be used for feature matching.

Abstract: For providing an efficient image pattern matching system, an image feature extractor (11) of the invention comprises a feature vector extraction means (101) for extracting a feature vector from the pattern image, a quality index extraction means (106) for extracting quality index information of the pattern image, an error distribution information storing means (105) wherein error distribution information representing correlation between error distribution of the feature vector and the quality index information is prepared, and a confidence attribution means (107) for obtaining confidence estimation information referring to the error distribution information retrieved with the quality index information. The image feature analyzer (51) prepares the error distribution information. An image feature matching system collates feature information of an image pattern extracted by the image feature extractor (11) by comparing it to registered feature information.

Abstract: A fingerprint sensor includes an array of fingerprint sensing elements and associated active circuits and an impedance matrix filter connected to the active circuits for filtering the signals. The impedance matrix filter preferably comprises a plurality of impedance elements with a respective impedance element connectable between each the active circuit for each fingerprint sensing element and at least one other active circuit for an adjacent fingerprint sensing element. The impedance matrix filter may also include a plurality of switches with a respective switch connected in series with each impedance element. In one embodiment, the switches may be selectively operated to determine ridge flow directions of the fingerprint image. In addition, the ridge flow directions may be used to determined a core location of the fingerprint image. The switches may also be selectively operated to convert a gray scale fingerprint image to a binarized fingerprint image.

Abstract: A computer system and method determines the force and/or torque applied during the image acquisition stage of a biometric characteristic. Images with very high or very low pressure or high shear torque are rejected and user/operator is notified to re-acquire the image. Alternatively, the application of force and torque by the subject is restricted mechanically so that the images are acquired while the force and/or torque are within acceptable ranges.

Abstract: A fingerprint detector that uses a skin resistance sensing array for producing a sample trajectory signal when a fingertip is moved across the sensing array surface. The sample trajectory signal represents the electrical conductance changes in the resistance of ridges and valleys of the fingertip. The fingerprint detector also includes a sampling circuit coupled to a processor. In addition, a technique is disclosed for detecting and verifying a fingerprint by moving a fingertip relative to the skin resistance sensing array. The sample trajectory signal produced is translated into a digital signal by the sampling circuit. The processor receives the digital sample trajectory signal for comparison with a known reference trajectory signal. The processor produces a verification signal if a threshold probability that the same fingertip generated both signals is exceeded.

Abstract: The invention is a system and method for determining a correspondence between a point selected from a set of points extracted from one image and an another point selected from the second set of points extracted from another image based on similarity of relationships of attributes associated with segments attached to the points.

Abstract: To provide an apparatus for pre-selecting fingerprint cards having certain similarity to an S-card to be identified, at a high-speed, among a plurality of F-cards, an apparatus of the invention comprises: an F-side cluster index determination section (2) for designating a cluster wherein feature data of the plurality of F-cards are to be classified according to features extracted from the plurality of F-cards; an F-card feature storing section (3) for storing the feature data of the plurality of F-cards in the cluster designated by the F-side cluster index determination section (2); an S-card feature storing section (5) for temporarily storing feature data of the S-card; an S-side cluster index determination section (6) for designating clusters to be retrieved according to a combination of features extracted from the S-card; and a fingerprint card matching discrimination unit (8) for pre-selecting the fingerprint cards by comparing the feature data of the S-card with the feature data of the plurality of F-car

Abstract: The method and apparatus of the present invention provide for automatic recognition of fingerprint images. In an acquisition mode, subsets of the feature points for a given fingerprint image are generated in a deterministic fashion. One or more of the subsets of feature points for the given fingerprint image is selected. For each selected subset, a key is generated that characterizes the fingerprint in the vicinity of the selected subset. A multi-map entry corresponding to the selected subset of feature points is stored and labeled with the corresponding key. In the recognition mode, a query fingerprint image is supplied to the system. The processing of the acquisition mode is repeated in order to generate a plurality of keys associated with a plurality of subsets of feature points of the query fingerprint image. For each key generated in the recognition mode, all entries in the multi-map that are associated with this key are retrieved.

Abstract: A skin pattern image is filtered by convolution calculation on a real plane or product calculation on a Fourier transformed plane with each of two-dimensional filters prepared according to kinds of features to be extracted of the skin pattern image. Image intensity of each subregion of each filtered data is calculated. Feature of each subregion is represented by a feature parameter corresponding to a filter that gives a highest value of the image intensity of the subregion. An initial pattern of features thus obtained is smoothed to minimize an evaluation function. A filtered skin pattern image having pixel values of each subregion smoothed by a set of filters prepared for extracting a kind of features is further filtered by another set of filters for extracting another kind of features.

Abstract: A fingerprint image is divided into blocks of pixels. The blocks are determined to be within the foreground or background of the image. Each of the foreground blocks are assigned a block direction. If an image consists of the complete impression of the fingerprint, there should exist at least one path (ridge), composes of foreground blocks, which lies on both half planes of a coordinate system with an origin at the centroid of the foreground and that comes sufficiently close to the x axis once the path crosses to the second half plane of the coordinate system.

Abstract: A tenprint selector comprises a fingerprint pattern level feature difference calculating unit which receives and compares a set of candidates for pattern level feature types of fingerprint images shown on file cards and a set of candidates for pattern level feature types of fingerprint images shown on a search card and calculates a pattern level feature difference, a card difference calculating unit which calculates a card difference based on the pattern level feature difference of the fingerprint images of all fingers shown on the file cards and the search card, and a judging unit which compares the card difference determined by the card difference calculating means with a predetermined card difference threshold value and judges, whether the file card shall be selected to be further checked with the search card.

Abstract: A system for converting an image-enhanced digitized raster fingerprint image to vector lines in order to generate a unique identification value for the fingerprint. The raster image pixels are converted to vector lines along the fingerprint ridges and the vector lines are classified and converted according to type. The line types are then analyzed and a list of identification features corresponding to the vector line types is generated. The identification features between the vector line types are compared and the image is classified according to fingerprint class. A unique identification value is then generated by numerically encoding the classified identification features.

Abstract: A method for automatic fingerprint classification is dependent on the number of core points and the ridge flow direction around the core points. The speed of the classification process is improved by pre-processing the fingerprint image to identify the background blocks and the fingerprint blocks, so that the process only deal with the fingerprint blocks. A block directional image is constructed for the fingerprint blocks. The block directional image is then used to determine the core point(s) of the fingerprint. Based on the number of core point and the trend of the ridge direction around each core point, fingerprints can be classified into 8 classes based on a set of predetermined rules.

Abstract: A fingerprint image is divided into blocks of pixels. The blocks are also determined to be within the foreground or background of the image. A dryness process determines a mean intensity of pixels within each foreground block, a second mean intensity of pixels for those pixels whose intensities are smaller than the mean intensity, a standard deviation of intensities of all pixels within the respective foreground block, and a contrast measure being a function of a first ratio of the second mean intensity to the standard deviation. A comparator that determines that the foreground block is a dry block if the contrast measure is larger than a dryness threshold and that the image is a dry image if a second ratio of the number of dry blocks to total number of foreground blocks is larger than a third dryness threshold.

Abstract: A method and an apparatus for upgrading an existing personal control system. The upgrade is achieved by replacing the personnel data input unit of an existing personal control system with a biometric interface device capable of reading physical characteristic and an access control signal in the format of the existing personnel control system.

Abstract: A facility is provided for correcting fixed column noise that may appear in a fingerprint image acquired from a capacitive fingerprint sensor. In particular, corrective gain and offset values are determined for each column of pixel signals generated by the sensor and are applied to such signals to greatly diminish the fixed column noise that may be present in that column.