IN MEMORY OF NORMAN PERLE
AUDIO/VIDEO FORENSIC INNOVATOR
High Tech Profile On
Norman Perle And His
NATIONAL AUDIO/VIDEO FORENSIC LABORATORY
Compiled By Ralph D. Thomas
When it comes to high-tech investigative/forensic technology in the private
sector, one of the most interesting and accomplished professionals I have had
the pleasure of meeting and getting to know is Norman Perle. Norman is to the
investigative audio/video forensics what Joseph Seanor is to the private
investigator and the Internet. Norman's lab is Northridge California is filled
with all sorts of computer equipment he uses in audio and video analysis and
Briefly, Mr. Perle has been in business approximately
20+ years working with recorded evidence. He has testified in more than 100
trials as an accepted Expert Witness in all aspects of recorded
laboratory he works in has the most recent and advanced computerized analysis
processing instruments for audio and video available
A "high profile case in which Norman was involved was the RODNEY KING Arrest Trial in Simi Valley, California. He was the only private facility which the Court ordered the
Holiday video released to. His work in that case, among other services provided, involved
extracting audio from the video, filtering the helicopter noise out in order to obtain
intelligible words and sounds of the arrest. This includes what the Police Officers were saying
as well as providing the Defense Team with Video Enhancements.
This techno-slueth was the Video Imaging Expert for the defense in the LOS ANGELES RIOT - Trucker
Denny Case. His complete Case Roster includes such cases as the DELOREAN CASE and U.S.A. v. BERNARBE-RAMEREZ (Camarena Drug Agent Case). Another noteworthy case he performed services on was a video recording of Compton California Police Officer involved in what one would describe as a violent arrest. His initial evaluation and analysis indicated the video tape was less than authentic, in that it clearly contained signs suggestive of falsification. Two days after this determination was made the person from whom the video originated stated, on a television news report, that the video tape had, in fact, been partially erased. This was only one of the problems with this video.
Additionally, Norman was the Audio Expert hired by the City of Los Angeles in defense of a City
Councilman accused of sexual harassment. A tape recording presented as evidence at trial by
the victim was shown to be falsified. The case against the City Councilman was dismissed.
Mr. Perle's Lab has a menu of services that include:
- RECORDING CONVERSIONS (audio/video)
- RECORDING DUPLICATION (audio/video)
- EXPERT WITNESS TESTIMONY/DESIGNATION
- VIDEO IMAGE & MOTION ENHANCEMENTS
- AUTHENTICATION ANALYSIS FOR ADMISSIBILITY (audio/video)
- NOISE REMOVAL/SOUND ENHANCEMENT
Since each case presents unique circumstances, consultations are offered to discuss cost
effective management of the forensic evidence material.
Evaluation of 3M Company TPR recording system tapes are made on an individual basis. In
order to quote a fee, the following information should be provided.
THIS SERVICE IS OFFERED ONLY ON RE-RECORDINGS.
Original material MUST be converted to MASTERS
Duplication of Audio Cassettes, up to 45 minutes per side is accomplished on professional
high speed duplicators.
NOTE - you should not put original/source recordings in a Duplicator Video Duplication is evaluated on a per case basis.
EXPERT WITNESS TESTIMONY:
Expert witness testimony includes Depositions and is charged on a flat day fee basis with no
provision for fractional days.
EXPERT WITNESS DESIGNATION:
A Client may designate N.A./V.F.L. as their Expert after an assignment is accepted. In those
cases wherein designation is forced, by virtue of a time constraint, there is a fee which must
be discussed prior to designation.
VIDEO IMAGE ENHANCEMENTS:
This process uses the IDENTI-F.I.E.(tm) Computer Image Acquisition system. Generally, a
target image can be enlarged, brightened, and sharpened. Images can be brought back into
focus, brought out of the darkness, and flares from lights pointing into the camera can be
reduced enough for identification of surrounding detail. The final product can be enlarged to
poster size or high resolution overhead transparencies.
ACCURATE (LITERAL OR TIME LINE) TRANSCRIPT SERVICE
An evidence recording that contains areas which are UNINTELLIGIBLE or that are not clear
enough to play in Court is a candidate for this service. The process
for producing a Certified
Accurate Transcript is focused on each utterance,
creating a literial or time scale transcript.
Each word is worked
individually through sophisticated computerized filters and
AUDIO RECORDING AUTHENTICATION:
is a two part process. The first part, called the Preliminary Analysis, involves
in-depth computerized review of the audio signal. This analysis is usually
re-recording, generally supplied by the prosecution, and will
document any deficiency
suggestive of editing or falsification. This process
will also determine if the recording
contains this classification of
deficiency, and if so, a Declaration is produced which supports
Motion to Release Original Evidence for a forensic analysis.
Analysis addresses whether the recording starts at the beginning and stops at
end, with no unannounced re-starts. If there are any
erasures/over-recordings, and if, in fact,
the recording is the
The Forensic Analysis is the scientific
evaluation of the audio signal as well as the actual
magnetic field on the
tape itself. Specific comparative tests are conducted on the tape
with Exemplars of stops/starts/re-starts/erasures in order to
determine if, in fact the tape is an
VIDEO RECORDING AUTHENTICATION:
This process for
authentication follows a similar procedure as that for audio. There are
technical differences which must be discussed, such as FORMAT, RECORDING
NOISE REMOVAL/SOUND ENHANCEMENT:
procedure involves a computer analysis of the frequencies that will be targeted
reduction or enhancement. The material is re-recorded a number of times
through a series of
filters, frequency enhancers and expanders which can drop
out or amplify a targeted range.
The computers used in this area are
dedicated signal processing units that can increase the
signal, but not the
DISCLAIMER: The client should understand that they are
buying our BEST EFFORT. We do
not guarantee anything else.
VOICE IDENTIFICATION & COMPARISON:
The VOICE PRINT
process is a two part procedure. The first part is a qualifing analysis
the UNKNOWN VOICE on the evidence recording.
spectrographic analysis is the format for display. Unique characteristics of
utterance is displayed in three formats. Frequency breakdown for analysis
of shape, time axis
of each Formant (frequency ingredient), and
A large percentage of recorded evidence in this catagory does
not meet the technical standards
necessary to conduct a comparative analysis
with a suspect.
This is due to the technical complexities comparing the
frequencies, shape, time base, etc., of
the recorded utterances. And the
quality of the environment and voice are also considered to
arrive at a
For those recordings that do qualify, a report is issued
which includes the instruction for
obtaining Exemplars of speech from
ABRIDGED CASE ROSTER
California Federal District (San Jose)
Authenticity of evidence recording; specific testing and procedures.
aspect of this case invloves a broken tape recorder represented as the source
Testimony regarding attributes of surveillance video purported
to show Defendant. Video
Enhancement show that the perpertrator has different
features. Testimony regarding process,
Defendant was found Not
Testimony specifics regarding falsified
evidence recording, supportive technical documentation
of analysis and
Testimony regarding Spectrographic
Analysis of Unknown Voice on evidence recording
relative to identification
and comparison. Evidence recording contained 10 clear utterances
taken from a
telephone message and was technically insufficient for use for use in
regarding audio track from surveillance video. Literal transcript,
processing, spectrographic analysis for interpretation of
recorded voiced utterances.
FOR THE CITY OF LOS
Testimony regarding falsified evidence recording, supportive
technical documentation of
examination and analysis. Tape recording was 30
minutes per side. On Side 1 only 6 minutes
of recorded conversation with a 24
minute erasure. Within the first 6 minutes there were 64
Testimony regarding technical aspects of evidence
photographs of a corpse. Accuracy of
detail, color balance, and distortion
were at issue.
Testimony regarding Voice
Identification and Comparison using Spectrogram Charts,
etc;, (Kelly-Frye 402 hearing)
falsified evidence recording, supportive technical documentation of
Defendant spent 4+ years in jail awaiting trial. Charged
with 2 counts of Murder, 7 counts of
released with all charges dropped.
regarding attributes of surveillance video purported to show Defendant touching
store clerk's breast. Enhancements and technical presentation show, in
fact, there was no
touching. Prosecution presented edited time lapse version
which created false perceptions.
Defendant was acquitted of the charge of
Testimony regarding attributes of
surveillance video purported to show Defendant. Video
perpetrator has different features.
regarding falsification of recorded evidence. Documentation, analysis
examination details, training and
Testimony regarding falsification of
Testimony specifics : Video
imaging / Enhancements / Audio Enhancements / Voice
Testimony specifics regarding Video Image
Federal District - Orange County
Testimony specifics regarding authenticity of tape recorded
LOS ANGELES RIOT/DENNY TRUCKER
Testimony specifics regarding Video Enhancements and
regarding Voice Identification, procedures, training and qualifications.
Peo. v. Koon, et al. (RODNEY KING, SIMI VALLEY
Testimony specifics : Video Enhancements and Audio
Enhancements directly from the original
COMPLETE ROSTER, WHICH INCLUDES ATTORNEY AND
CITATION CASE NUMBER, SHOULD BE
MADE ON LETTERHEAD, via U.S.
8357 Shirley Avenue
Northridge, Ca., 91324-4146
993-8550 / VOICE (818) 989-0990