Belonging to courts of judicature or to public discussion and debate, is the common definition of forensic. Forensic photography as used by law enforcement agencies, the fire services and industrial security employs a variety of camera equipment as well as numerous types of photographic emulsions. Identification of persons, objects and activities, often under adverse lighting conditions, make use of photographic materials that originally and normally were intended for entirely different purposes. The liberal attitude of the courts in todays society makes the use of photography imperative. Special techniques using filters, modified developers and specific light sources allow photography to play an ever increasing role in law enforcement.
The U.S. Customs Service continues to use the infrared imaging technology to aid in the interdiction of illicit drugs. The imagers in use include several handheld thermal viewers and several AAS-36 FLIRs integrated to the U.S. Customs Service Citation aircraft. The future will see several more AAS-36 FLIRs and may see lower cost FLIRs integrated to patrol boats, patrol vehicles and lightweight, long range aircraft. In the past year, the U.S. Customs Service has begun looking at several new promising scenarios, two of which are described in the paper along with preliminary results in evaluating the use of IR technology for these applications. The first involves the use of IR imagers for passive surveillance of vessels suspected of carrying contraband. The second involves the use of low cost IR technology on board lightweight, long range and lower cost aircraft for passive tracking of incoming suspect aircraft. Both of these scenarios depend on the efficient use of the IR technology in streamlined, cost effective interdiction procedures.
This paper briefly describes some of the past and present optics projects that have been undertaken by the Scientific Research & Development Branch of the Home Office. There is a strong emphasis on carrying through. the results of research. into industry so that the police can fully benefit from this work.
The results of a survey are given in which it is shown that there are a considerable number of photographs in police hands that are not usable. A digital computer system is described which is being used in an attempt to improve the quality of some of this operational material. A wide range of enhancement and restoration procedures that have been implemented are described. Finally the results of these efforts to date are summarized.
Informal experiments have been performed which lend credence to the hypothesis that facial thermograms can be of substantial value in detection of disguises and in positive identification of known individuals. Facial thermograms appear to be significantly more unique to an individual than standard photographs, and are also significantly less affected by illumination conditions. A program of formal experiments is suggested (1) to verify the hypothesis that thermograms constitute "facial fingerprints," and (2) to evaluate simple data extraction techniques for real-time automated identification of known individuals.
Optical nondestructive readout of photographic film allows the forensic photographer to see image detail despite overexposure, underexposure, or both. The methods involve direct schlieren viewing of the surface relief image of the original negative. A "super camera" largely insensitive to range and brightness variations in the scene is described.
An analysis of of high speed stop-motion shutter television cameras and video recorders and their applications in law enforcement: Speed Analysis and Enforcement, Airborne Mapping and Location File, Testing and Adjustment of Training, Crash Studies, Road Sign Analysis, Traffic Flow Analysis, Laboratory Analysis, and Vehicle Log.
The requirements imposed upon image processing systems vary significantly as a function of the application. Imagery generated and used for legal purposes imposes needs for processing which typically are different from other disciplines where imagery is applied to the solution of problems. The basic operations by which imagery is manipulated are more similar than different from field-to-field; however, the combinations of functions applied to the imagery, and the purpose of the processed data or image, are what set each complete processing system apart. This series of papers will illustrate, by example and description of dedicated facilities, the most effective image processing operations used by the legal and law enforcement communities. The community's influence on system design has led to unique image processing operations; however, a combination of multivaried needs and a relatively limited application of image processing to "legal" problems place the state of this technology in an evolving mode. Feedback from the evolution has led to our prescription for the design of a digital image processing system for legal applications.
In Part I of this series we developed an architecture for a Legal Image Processing Laboratory. The complexity and sophistication of the required operations were developed from the multiplicity of image sources, degrading influences and desired results. The final objective, either directly or indirectly, was shown to be an improvement in the image information content or an extraction of operational data. The image processing operations were categorized into the following three: Restoration, Measurement, and Correlation. In Part II, we now illustrate the basic operations with additional examples. The architecture remains as defined in Part I.
An automatic vehicle surveillance system is conceived for capturing license plates consisting of three major functional components: image capture, image processing, and communications. Image capture is provided by a high-speed, high-resolution TV camera, an illuminator, and an image storage medium. Image processing is performed by an analog to digital conversion of the rear view image of a vehicle, a method of automatically finding the license plate in the image, and a method of identifying the alphanumerics and the state of issue of the license plate. The license plate characters are sent to a law enforcement computer data base through a communication link where a check is made of the registrant. This paper discusses the design requirements of a system with these three functional components. The results are presented of a study for establishing the image quality required for a license plate finder and character recognizer to perform reliably.
Applications of Second Generation Microchannel Plate (MCP) image intensifiers are discussed. Principles of operation are reviewed and performance advantages pointed out. Improvements now being phased into production are described. Finally, several applications in law enforcement are given.
A low-cost, battery-operated surveillance system was developed for use in international nuclear safeguards. The resulting system utilizes components of the commercial Polavision instant movie system to provide single-frame color or black/white images which are automatically developed and displayed by a portable Polavision Player whenever it is desired to stop and view the film. The system is designed for long-term unattended use, triggered by a timer or other input signal. To provide positive assurance of continuing operation, a self-diagnostic module was designed to detect the most common failure modes and transmit real-time status data to a remote location. The resulting system provides a low-cost surveillance capability which may be useful in various law enforcement applications.
A. Hecht. Welcome to the panel session of the ''Optics and Images
in Law Enforcement II 7 ' conference entitled 'Technology in Law
Enforcement. 7 ' We will try to relate technology and its application
in the real world of public and public courts. The panel discussion
will be moderated by G. Robert Blakey. He is currently associated
with the Notre Dame Law School where he is a Professor of Law.
He was formerly chief counsel of the Senate Subcommittee on
Criminal Law and Procedures in 1969 and 1972. Professor Blakey
was chief counselor and staff director on the House Select Committee
on Assasinations from 1977 to 1979. He received his JD in
1960 from the University of Notre Dame Law School. He was
given by the American Academy of Forensic Sciences its 1979
Award of Merit for outstanding service to the Academy in advocacy
of public recognition and appreciation of the forensic sciences.