International Business Machines Corporation

Aspi B Wadia

James M White

Paul A Hakenewerth

James R Walker

Steven C Gunderson

Apparatus and methods are described which take advantage of the peculiar characteristics of dynamic signature data while segmenting and compressing such data for storage on a limited capacity device. Compression is accomplished by digital oversampling, segmenting, filtering, decimating and later interpolating reference signature data, thereby allowing storage in compressed form without significant matching degradation. The pen down and pen up information which define signature segments is separated from the pressure waveform and stored in a separate array for each reference signature. The acceleration and pressure data are then filtered, decimated and stored for each reference signature. Later, during identity verification, the stored acceleration and pressure data are restored to an oversampled rate by interpolation. To verify the identity of a person supplying a trial signature, each segment of the trial signature is compared with corresponding segments of one or more of the stored reference signatures.

Signature verification data compression for storage on an identification

Improved method and apparatus are provided for hand dimension verification. A two dimensional scanner provides image data from top and angled scans to an image processor which processes this data to develop invariable hand measurements using reference points located from contour sequences generated from the image scan data. The reference points are located so as to be immune from variations introduced by fingernail length, hand pressure and finger spread. Finger width measurements are made using certain reference points and finger width variations are used to determine the presence of abnormalities which could be natural or introduced by wearing of jewelry. The finger width variations are in effect removed by locating finger contour points at the beginning and ending of the variations and using finger slope data for trimming and thereby provide invariable finger width measurements together with finger thickness, finger length and hand area measurements for hand dimension verification.

Hand dimension verification

A scanner for scanning an increased area of a finger held or pressed on a concave elliptically cylindrical surface having two focal axes includes a linear light source positioned at one focal axis of a first reflective cylindrical elliptical surface, the other focal axis coinciding with one focal axis of the concave elliptical surface in contact with the finger. A second reflective, cylindrical elliptical surface has two focal axes where one of the axes coincides with the position of a linear array combination of photosensitive elements and charged coupled devices and the other coincides with the other focal axis of the concave elliptical surface in contact with the finger. The linear light source resides within a scanning drum having a longitudinal opening or slit and suitable rotated whereby a line of light is projected along the cylindrical elliptical surface of the first reflective surface whereby light rays are reflected to the finger contact surface to scan a finger held thereon and then totally internally reflected to the second reflective surface and then reflected therefrom as an image on the linear array.

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Charlotte, NC, United States of America

Aspi B Wadia