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Forensic Video Image Analysis An Emerging Tool
for Law Enforcement, Industrial Security,
and the Courts
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Original Image - VHS Format
Man wearing hat carrying purse - Boston
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Magnification X2 - Deblurred
Man wearing hat, glasses carrying purse - Boston
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Forensic Video Image Analysis No one recognizes
themselves better in enhanced video than the
perpetrator. ergo - plea bargains and cost
savings for the investigator and the Court
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Magnification X4 - Deblurred
Man with hat, glasses, thick eye brows purse -
Boston
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Magnification X8 - Deblurred
Man with hat, glasses thick eyebrows - Boston
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Facial Marking - Original Image
Perpetrator at ATM machine - Reno
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Facial Marking - Image Deblurred
Perpetrator at ATM machine - Reno
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Magnification X2 - Deblurred Facial marking is
more distinct
Perpetrator at ATM machine - Reno
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Magnification X4 - Deblurred Facial marking
distinct
Perpetrator at ATM machine - Reno
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LESSON SYNCHRONIZATION
PARTIAL FRAMES CAN BE CAPTURED
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Original Image - 24 Hour Mode First image
captured at 211805
There are 5 frames in one second in
24 hour mode 10 fields!
very dark hard to see perp
Tape very difficult to sync on one frame
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Original Image - 24 Hour Mode Second image
captured at 211805
There are 5 frames in one second in
24 hour mode 10 fields!
very dark hard to see perp
Tape very difficult to sync on one frame
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Original Image - 24 Hour Mode Third image
captured at 211805
There are 5 frames in one second in
24 hour mode 10 fields!
very dark hard to see perp
Tape very difficult to sync on one frame
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Original Image - 24 Hour Mode Fourth frame
captured at 211805
There are 5 frames in one second in
24 hour mode 10 fields!
very dark hard to see perp
Tape very difficult to sync on one frame
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LESSON Splitting Frames into Fields
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One frame of video is composed of odd even
lines. The odd lines are called the Odd
Field The even lines are called the Even Field
Splitting Frames into Fields
Vertical Magnification enlarges fields to
full frames
The computer can display the odd even fields
separately
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Video Frame 525 Lines
even lines
odd lines
NTSC Format 2 to 1 Interlace
30 frames/second
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Video Frame Field Split
1
3
5
7
Odd Field
9
11
13
15
211
2
4
6
Even Field
8
10
12
14
210
212
60 fields/second 212.5 lines/field
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Original VHS Continuous Tape Ghost Perpetrator
Perp in upper right corner of convenience store.
He is every other line of video.
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Ghost Perp Odd Field 212.5 lines
Ghost Perp Even Field 212.5 lines
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Ghost-Even Field Magnified Vertically X2
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Software Time Base Correction
The perps head is now in alignment
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Ghost - Even Field Magnified X2
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Ghost Even Field Magnified X4
Aspect Ratio Corrected
Mug Shot of Perpetrator
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LESSON MOTION BLUR A Solution
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One frame of video is composed of odd even
lines. The odd lines are called the Odd
Field The even lines are called the Even Field
Splitting Frames into Fields removes MOTION BLUR!
Vertical Magnification enlarges fields to
full frames
The computer can display the odd even fields
separately
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Original VHS Tape - Motion Blur
Perpetrator Running Through Convenience Store.
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Motion Blur Magnified X2 Brightened
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Original Image Brightened Time Base Corrected
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Frame Split Into Odd Even Field
This process removes motion blur
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Odd Field Magnified Vertically X2
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Odd Field Magnified X2
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VHS / SVHS Continuous or Time Lapse

8mm VHS Hi-8 SVHS
Thermal / IR Images Still Photos - Positive
Negative
All formats are acceptable!
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Premeditated Murder ? Perp holds gun to clerk
outside window.
White rag held over weapon.
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Premeditated Murder ? Perp enters store holding
weapon covered by rag .
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Premeditated Murder ? Magnification X2 - Notice
rag over weapon.
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Premeditated Murder ? Magnification X4 Notice
rag over weapon powder burn in rag.
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LESSON TAPE COPY
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Video Tape Copy
1. DO NOT copy VHS to VHS. Resolution
Intensity are lost. 2. DO make a VHS to
SVHS, 8 mm to Hi 8 mm, SVHS to HI 8 mm,
BETA to 3/4 or 1 format. 3. DO NOT make
several copies of VHS to VHS, i.e., second
and third generation tapes. The copies
loose more resolution with each generation.
3/4
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Original tape
Copy tape
Note loss of detail in copy
First generation VHS
Third generation VHS
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First Generation VHS
Third Generation VHS
Magnification X2
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Color Burst - Wavy Distortion
Loss of Image Detail
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Color Burst Signal Eliminated
Wavy Distortion Removed
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LESSON Remove Color Burst Signal
Split SVHS 4 pin mini DIN to Y/C BNC
For Highest Resolution, Finest Detail Images
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Definition Image Enhancement
To heighten intensify make greater increase
Source Websters Dictionary
Court Room Acceptable
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Definition Image Edit
To prepare assemble alter adapt refine
Source Websters Dictionary
Court Room Unacceptable
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LESSON To T or Not to T
Do not use BNC Ts on Video Signal Ts causes
intensity degradation
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VHS / SVHS
Continuous or Time Lapse
8mm
VHS
Hi
-
8 SVHS
Thermal / IR Images
Still Photos
-
Positive Negative
All formats are acceptable!
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Original Image Good Video
A Rare Case excellent video looking for a scar
pattern on forehead Pattern not apparent
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Magnification X2
A Rare Case excellent video looking for a scar
pattern on forehead Pattern not
apparent Magnification Optical Quality Times Two
with Resolution Enhancement
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Magnification X4
A Rare Case excellent video looking for a scar
pattern on forehead Pattern not
apparent Magnification Optical Quality Times Four
with Resolution Enhancement
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Original Image - dark, blurry, and grainy
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Image low pass filtered, deblurred, brightened
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Magnification X2, filtered, deblurred, brightened
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Quad Camera - Original Image Deblurred
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Magnification X2
Magnification X8
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LESSON PLAYBACK AZIMUTH
PLAYBACK MUST MATCH RECORD
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AZIMUTH /- 60 OFFSET RED - BROWN READ /
WRITE HEADS ENHANCES SIGNAL TO NOISE FOR LONG
PLAY MODES
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LESSON TAPE AUTHENTICITY
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FIELD SWITCH POINTS AND TRACEBACK
SIGNAL BOTTOM VIDEO LINE DISTINCTIVE SIGNAL
SHAPES ON SINGLE VIDEO LINE
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Tape Copy Determination by Characteristic Switch
Points Note the white dottad pole
shapedcircled in red
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Switch Point Peak Shape Line 478 Original Video
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Tape Copy Determination by Characteristic Switch
Points Note the white dottad pole shapedcircled
in red
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Switch Point Peak Shape Line 463 Copy Video
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Tape Copy Determination by Characteristic Switch
Points Note the white dottad pole
shapedcircled in red
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Switch Point Peak Shape Line 473 Copy Video
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4/3 Video Aspect Ratio Distortion Image Elongated
Fails Fair Accurate Representation Courtroom Re
quirement
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Unity Aspect Ratio Script File Calibrated Automati
c Satisfies Courtroom Requirements
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4/3 Video Aspect Ratio Distortion Image
Elongated Fails Fair Accurate Representation Cou
rtroom Requirement
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Unity Aspect Ratio Script File Calibrated Automat
ic Satisfies Courtroom Requirement
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Courtroom Standards for the Acceptance of
Scientific Evidence Daubert is a scientific
reliability test, which replaces the Frye test in
Federal civil and criminal cases, and is slowly
becoming the standard in State cases. Daubert v.
Merrell Dow Pharmaceuticals 113 S.Ct.2786 (1993)
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Courtroom Standards for the Acceptance of
Scientific Evidence Frye requires the general
acceptance of the technology in the particular
field in which it belongs. Frye v. United States,
293 Fed. 1013, 1014
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Courtroom Standards for the Acceptance of
Scientific Evidence Basic requirement which has
been placed upon the Forensic Photographer
requires that enhanced images be a fair and
accurate representation of the original images.
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Courtroom Standards for the Acceptance of
Scientific Evidence California Evidence Code
regarding the admissibility of live scan prints,
digital photographs, and digital latents. Video
or digital images admissible from the Legislative
Counsel's Digest, bill signed by Governor Pete
Wilson on August 19,1996.
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The End Product of a Forensic Video Image
Analysis should consists of the following VHS
tape and/or AVI File on a CD of all images, raw
and processed Dye Sublimation Hardcopy of the
best images print at 300 lpi (equivalent to 4800
dpi) Telecom discussion with the video
analysts Expert Witness testimony
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End Product The End Product of a Forensic Video
Image Analysis should consists of the
following VHS tape of all processed images
and/or all raw captured images with each image
recorded for three (3) seconds or user
selectable interval. Hardcopy of the results with
the best images printed on a dye sublimation
system (highest resolution for video hardcopy,
with the exception of 35mm slides). AVI File on
a CD with all the images, raw and processed.
Images should be sequentially numbered, dated,
with case file identification, and analyst
initials. For a in depth discussion of the
results, call the video analyst indicated by
initials on the images.