Mirror system and method for acquiring biometric data

Abstract

A system and method for obtaining biometric imagery such as iris imagery from large capture volumes is disclosed wherein a substantially rotationally symmetric mirror such as a cone or sphere is rotated at a constant velocity about a central axis.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority from provisional application 60 / 969,607, filed Sep. 1, 2007, which is hereby incorporated by reference. This International Application is also related to International Application Serial No.: PCT / US08 / 74737 (Attorney Docket GLOB0010-500), filed on even date herewith by the same applicant, which is hereby incorporated by reference.BACKGROUND OF THE INVENTION[0002]This invention relates to systems and methods for acquiring biometric and other imagery, biometric acquisition, identification, fraud detection, and security systems and methods, particularly biometric systems and methods which employ iris recognition with a camera having a field of view. More particularly the invention relates to systems and methods for very quickly acquiring iris imagery within a wide capture volume.[0003]Iris recognition systems have been in use for some time. The acquisition of images suitable for iris recognition is inherently...

AI Technical Summary

Benefits of technology

"The present invention aims to capture biometric data in large volumes with high resolution using fewer cameras or one camera. It solves the problem of prior art systems by using a continuous mechanical mechanism to stop and stare at one location before quickly jumping to another location. The invention includes a rotating curved mirror and tilting to create a frozen image, a sensor to acquire biometric imagery reflected off the mirror, and a reflection device with conical sections for iris recognition. The method involves configuring a sensor to view a scene reflected off a non-flat surface, mounting the surface on a rotating axis, and acquiring imagery of the scene reflected off the surface. The invention allows for large capture volumes and high-resolution imaging."

Problems solved by technology

The acquisition of images suitable for iris recognition is inherently a challenging problem.

This results in a small field of view and a small depth of field.

There is therefore a need to scan very quickly or else the person will have moved out of the capture volume or the subject's motion will cause a blur.

In the current state of the art, attempts to resolve this problem comprise using a flat mirror to scan but such attempts have not so far resolved the motion blur problem, especially when the camera is zoomed in.

The image motion in terms of pixels / second is very high which makes it very difficult to obtain high quality imagery with prior art systems in these situations.

Multiple cameras and lenses covering a larger volume is an obvious solution, but it requires the expense of additional cameras, optics and processing.

However approaches that point mirrors in such a fashion have to handle one or more key problems, namely: (i) the time latency involved in moving the camera to a location, (ii) vibration of the mirror and the resulting settling time of the mirror as it stops and starts motion, (iii) the complexity of the mechanical arrangement, (iv) the reliability, longevity and expense of the opto-mechanical components for such a moving assembly.

The problem with that approach is that it is very expensive or physically impossible to use such a mechanism to point at 2 or 3 places in a scene at a very high rate—for example, 5-50 times a second.

In addition, there is substantial settling time for the mirror or camera to stop vibrating as the mirror or pan / tilt assembly stops before imagery is acquired, so essentially it makes it almost physically impossible to scan at such high rates.

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