Scanner includes transducer, acoustical drive, acoustical receiver, X and Y position indicators, and cathode-ray tube. Transducer sends ultrasonic pulses into shoe sole or shoeprint. Reflected signals are picked up by acoustic receiver and fed to cathode-ray tube. Resulting display intensity is directly proportional to reflected signal magnitude

Derr, L. J.

English

NASA Technical Reports Server

Scan Surface Scanning	 Shoeprint in Dirt or Transducer.- Soft Surface 
November 1974	 B74-10212 
NASA TECH BRIEF 
is
	
NASA Pasadena Office 
NASA Tech Briefs -announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Ultrasonic Scanner for Footprint Identification 
The problem: 
Shoeprints found in crime areas are often used by 
investigators to identify criminals. This procedure is 
much less accurate than fingerprinting. It is possible to 
misidentify an innocent person simply because his shoe 
soles match those of a criminal. 
The solution: 
An ultrasonic scanner is used for a more accurate 
matching between shoeprints and shoes.
How it's done: 
Every shoe worn on a hard surface develops a density 
pattern, or a footprint, on the sole. This pattern is also 
traceable on shoeprints found in dirt. By comparing 
the foot shape on a shoe sole with one on a shoeprint 
in dirt, an investigator can identify a criminal with 
improved accuracy. This comparison is done with the 
help of an ultrasonic scanner. 
The ultrasonic scanner as shown in the illustration 
includes a transducer, an acoustical driver, an acoustic 
receiver, X and Y position indicators, and a cathode-ray 
tube. The transducer which is fed by the acoustical 
driver is used to send ultrasonic pulses into a shoe sole 
or a shoeprint. The reflected signals are picked up by 
the acoustic receiver and are fed to the cathode-ray 
tube. The resulting display intensity is directly pro-
portional to the reflected signal magnitude. Stronger 
signals come from denser areas, or areas where the foot 
has rested. 
Density Pattern in 
Shoe Sole and 
Shoeprint for 
Comparison 
0,' 
Li 
--% c-i •1 Acoustic	 Z Axis Receiver	 Modulation Cathode-Ray Tube 
X Position 
Indicator
Photofilm 
Acoustical 
Driver	 V Position 
Indicator 
Uniform-Density Casting
Ultrasonic Scanner System
(continued overleaf) 
This document was prepared under the sponsorship of the National	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	
information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	
will be free from privately owned rights. 
https://ntrs.nasa.gov/search.jsp?R=19740000212 2020-03-17T13:50:42+00:00Z
Normally, two scans are made, one of the shoeprint 	 Patent status: 
and the other of the shoe sole taken from a suspect. The 	 NASA has decided not to apply for a patent. 
displays are photographed, and the photographs are 
compared for identity.
	
	
Source: Lloyd J. Derr of

Caltech/JPL 
Note:	 under contract to 
Requests for further information may be directed to: 	 NASA Pasadena Office 
Technology Utilization Officer	 (NPO-13055)
NASA Pasadena Office 
4800 Oak Grove Drive 
Pasadena, California 91103 
Reference: TSP74-102 12 
B74-10212	 Category 03


Ultrasonic scanner for footprint identification

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