Digital Images as Evidence

1
Digital Images as Evidence

• Karl Harris
• Computer Science 99
• Dartmouth College
• February 29, 2000

2
Introduction

• Digital Image Enhancement is a process in which a
  digital image is enhanced so that more detail can
  be seen
• This process has many applications
• Entertainment such as movies and art
• Law Enforcement
• It is such a new technology that the legal system
  is struggling with how digitally enhanced images
  can be used as evidence

3
Topics of Discussion

• The Reginald Denny beating and trial
• Cognitech, Inc.,and the future of digital image
  enhancement
• Ethical and legal ramifications of this technology

4
The Reginald Denny Case

• On April 29, 1992, trucker Reginald Denny is
  severely beaten as he leaves his truck to help
  other victims during the LA Riots
• Damian Williams and Henry Watson are charged with
  attempted murder
• Because there are no clear photos and few
  witnesses, digital image enhancement is used by
  Cognitech to identify Williams as an assailant in
  the trial.

5
The Sequence of Events

• Sept. 11, 1993
• An enhanced image showing a cheek blemish and a
  stain on a T-shirt links Williams with a liquor
  store robbery and the beating
• Sept. 15, 1993
• Cognitech enhances an image taken from a
  helicopter showing the beating. It shows a
  tattoo of a rose on Williams arm.
• The jurors are allowed to see enlarged photos of
  the beating, but not the enhanced images

6
The Sequence of Events

• Sept. 16, 1993
• Judge Ouderkirk rules that Cognitechs process to
  enhance the video is reliable enough to be used
  as evidence
• Leonid Rudin, director of Cognitech, testifies
  that there is definitely something on the man in
  the photos arm and that it is consistent with
  Williams tattoo
• When asked if he knew if the spot was grease,
  dirt, or a tattoo, he answers that he does not

7
Cognitech and the Future

• After the Denny Case, Cognitechs top executives
  believed there could be a multi-billion dollar
  business in image enhancement for law enforcement
• There are many applications
• Video surveillance in convenience stores, parking
  garages, and ATM machines
• Insurance claims
• Acquittals

8
What is the Law?

• An original of a writing or recording is the
  writing or recording itself or any counterpart
  intended to have the same effect by a person
  executing or issuing it. An original of a
  photograph includes the negative or any print
  therefrom. If data are stored in a computer or
  similar device, any printout or other output
  readable by sight, shown to reflect the data
  accurately, is an original - Federal Rules of
  Evidence

9
Ethical and Legal Implications

• Digitex - digital, editing, and special effects
  used to manipulate images
• With digitex, even experts will be unable to
  determine if images have been altered
• Judges - exclude all photographic evidence?
• New ethical situations
• Wrongful convictions or acquittals due to
  mistakes in the image enhancement
• To what extreme do we go?

10
What can be done?

• Keep the source media intact showing the original
  directory with dates, files, sizes, and names
  generated by the camera
• Find better ways of analyzing digital images to
  detect tampering
• Make better and newer laws. Without a clear
  legal precedence the is no framework to start
  from.

11
Summary

• The Reginald Denny case brings into question the
  use of digitally enhanced images as evidence in
  court
• The Federal Rules of Evidence say a digital
  image, enhanced or not, is just as good as a
  photograph from film
• There are many dangers associated with admitting
  digital images as evidence in a trial