Low power fingerprint capture system, apparatus, and method

Abstract

The present invention provides a large format fingerprint capture apparatus, system and method that is low power, compact, and lightweight and has a platen area greater than 3.0 square inches. The present system is typically powered, controlled, and exchanges data over a single data/control/power connection to a host PC, e.g., a desk top computer, PDA, or laptop computer although the system can also be used in a wireless fashion with a power subsystem so no physical connections are required. The system typically includes a light source, a prism, a camera (including the lens), and a case. Optional elements comprise holographic elements such as gratings and holographic optical elements (HOEs), a battery subsystem, magnetic stripe reader, barcode reader, platen heater, platen blower, and mirrors to divert the image beam.

What is claimed is: 
     
         1 . A system configured to generate a composite image of a friction ridge signature of a subject, the system comprising:
 a platen comprising a first light-reflecting surface;   a light source configured to emit light rays to illuminate a subject placed in contact with the first light-reflecting surface of the platen;   a camera configured to capture images of the subject in contact with the first light-reflecting surface of the platen, through the platen, in an ongoing manner; and   a processor configured to receive images of the subject captured by the camera, and to automatically determine whether a sequence of the received images includes a successful capture sequence,
 wherein the processor is configured to generate, responsive to determination that the sequence of received images includes a successful capture sequence, a composite image, wherein the composite image is formed from the images included in the successful capture sequence. 
   
     
     
         2 . The system of  claim 1 , wherein the processor is configured to determine a type of capture sequence, and to determine whether the sequence of received images includes a successful capture sequence of the determined type. 
     
     
         3 . The system of  claim 2 , wherein the type of capture sequence comprises a roll capture or a slap capture. 
     
     
         4 . The system of  claim 1 , wherein the processor is configured to generate the composite image by merging the images included in the successful capture sequence. 
     
     
         5 . A method of generating a composite image of a friction ridge signature of a subject, the method comprising:
 emitting light rays toward a platen comprising a first light-reflecting surface to illuminate a subject placed in contact with the first light-reflecting surface of the platen;   capturing images of the subject in contact with the first light-reflecting surface of the platen, through the platen, in an ongoing manner;   executing one or more modules on one or more processors to automatically determine whether a sequence of the captured images includes a successful capture sequence; and   generating, responsive to determination that the sequence of the captured images includes a successful capture sequence, a composite image, wherein the composite image is formed from the images included in the successful capture sequence.   
     
     
         6 . The method of  claim 5 , wherein determining whether a sequence of the captured images includes a successful capture sequence comprises:
 determining a type of capture sequence, and   determining whether the sequence of captured images includes a successful capture sequence of the determined type.   
     
     
         7 . The method of  claim 6 , wherein the type of capture sequence comprises a roll capture or a slap capture. 
     
     
         8 . The method of  claim 1 , wherein the composite image is generated by merging the images included in the successful capture sequence. 
     
     
         9 . A system configured to generate a composite image of a friction ridge signature of a subject, the system comprising:
 a platen comprising a first light-reflecting surface;   a light source configured to emit light rays to illuminate a finger of the subject placed in contact with the first light-reflecting surface of the platen;   a camera configured to capture images of the finger of the subject in contact with the first light-reflecting surface of the platen, through the platen, in an ongoing manner; and   a processor configured to receive images of the finger of the subject captured by the camera and determine whether the finger of the subject is being rolled across the first light-reflecting surface based on the received images, the processor configured to determine image parameters for individual ones of the received images, the image parameters including a location parameter that indicates a location of the finger of the subject on the first light-reflecting surface of the platen.   
     
     
         10 . The system of  claim 9 , wherein the processor is configured such that the received images include a first image of the finger in a first location, and a second image of the finger in a second location, the first image being captured by the camera before the second image,
 wherein the processor is configured to determine a first location parameter for the first image and a second location parameter for the second image, and   wherein the processor is configured to determine whether the finger is being rolled across the first light-reflecting surface based on a comparison of the first location parameter and the second location parameter.   
     
     
         11 . The system of  claim 10 , wherein the processor is configured to determine a first movement direction and a first movement distance based on the comparison of the first location parameter and the second location parameter. 
     
     
         12 . The system  claim 11 , wherein the processor is configured to determine that the finger of the subject is being rolled across the first light-reflecting surface responsive to the determined first movement distance breaching a distance threshold value. 
     
     
         13 . The system of  claim 9 , wherein the processor is configured such that the location parameter includes two-dimensional coordinate information representative of a bounding box that indicates the location of the finger of the subject on the first light-reflecting surface of the platen. 
     
     
         14 . A method of generating a composite image of a friction ridge signature of a subject, the method comprising:
 emitting light rays to illuminate a finger of the subject placed in contact with a first light-reflecting surface of a platen;   capturing images of the finger of the subject in contact with the first light-reflecting surface of the platen, through the platen, in an ongoing manner;   receiving images of the finger of the subject captured by the camera; and   determining whether the finger of the subject is being rolled across the first light-reflecting surface based on the received images, the determination of whether the finger of the subject is being rolled across the first light-reflecting surface including determining image parameters for individual ones of the received images, the image parameters including a location parameter that indicates a location of the finger of the subject on the first light-reflecting surface of the platen.   
     
     
         15 . The method of  claim 14 , wherein the received images include a first image of the finger in a first location, and a second image of the finger in a second location, the first image being captured by the camera before the second image, the method further comprising:
 determining a first location parameter for the first image and a second location parameter for the second image, and   determining whether the finger is being rolled across the first light-reflecting surface based on a comparison of the first location parameter and the second location parameter.   
     
     
         16 . The method of  claim 15 , further comprising determining a first movement direction and a first movement distance based on the comparison of the first location parameter and the second location parameter. 
     
     
         17 . The method  claim 16 , further comprising determining that the finger of the subject is being rolled across the first light-reflecting surface responsive to the determined first movement distance breaching a distance threshold value. 
     
     
         18 . The method of  claim 14 , wherein the location parameter includes two-dimensional coordinate information representative of a bounding box that indicates the location of the finger of the subject on the first light-reflecting surface of the platen.