Download presentation
Presentation is loading. Please wait.
Published byBathsheba O’Connor’ Modified over 8 years ago
1
Document Analysis
2
Comparison of signatures and other writings Mechanical impression comparisons (e.g., typewriters, check writers, rubber stamps and seals) Identification of photocopy machines Typewriter make and model determinations Nondestructive examination of inks Deciphering water soaked, charred, or burned documents Deciphering indented writing on anonymous letters and other documents Torn and cut paper edge comparisons Printing and other duplicating processes analysis Spray-painted graffiti comparisons
3
Documents and Forensics Handwriting Analysis –Forgeries –Window to personality Psychological profile –Individualistic
4
Handwriting Traits Shapes of the letters and their slant, angles, connections, and curves The line quality, or the thickness of the line as a result of the type of writing instrument used and the pressure exerted while writing Spacing, alignment, formatting, and unique punctuation Spelling, phrasing, punctuation, and grammar
8
Do Now Write this on unruled paper “An ink is a liquid containing various pigments and/or dyes used for coloring a surface to produce an image, text, or design. Ink is used for drawing and/or writing with a pen, brush or quill.”
9
Handwriting and Personality Heavy pressure= Strong emotions Light pressure= not much emotional or physical energy Left slant=tries to avoid emotional situations (cold, indifferent) Right slant= emotionally responsive (caring, warm) Vertical letters= cool headed
10
Handwriting and Personality Imaginary Line Writing –Straight=tense, over-disciplined –Very wavy=emotional rollercoaster –Slant upward=optimism –Slant down=pessimism, depression, tired
11
Charles Manson (wavy baseline)
12
Handwriting and Personality Letter size: –Small= focused, maintains concentration, likes to work alone, conservative –Large= easily distracted, get off-track, Albert Einstein
13
Pencils Grades of Pencil –Related to hardness of graphite H=Hardness B=Blackness F=Finepoint
14
Inks –Solvents –Pigments –Dyes (History=plants, squid ink (sepia), burnt bones, tar) –Resins –Lubricants –Stabilizers –Fluorescesors –Particulate matter –Surfactants
15
Most Common Black Inks Carbon inks –Soot and binding agents –smudges Iron gall nut inks –Corrosive to paper –unstable –Fades to brown –Makes paper brittle
16
Paper Mat of roughed up fibers –Cotton or linen (rag fiber) and wood fibers
17
History of Paper 100 BC China –Mix finely chopped mulberry bark with hemp rags and water, strained, dried in sun 400 AD India
18
History of Paper In U.S. –Paper made by hand up to 1799 –1799 Fourdriner Paper Machine
19
Before Paper: Egyptians used mashed, lased, papyrus plant (3000BC) or clay bricks or skins
20
Paper Making See video
21
Paper Analysis Grade in Weight Tissue: Low weight, <40 g/m2 Paper: Medium weight, 40 - 120 g/m2 Paperboard: Medium High weight, 120-200 g/m2 Board: High weight, >200 g/m2 Colors Brown: Unbleached White: Bleached Colored: Bleached and dyed or pigmented
22
Paper Analysis Usage Industrial: Packaging, wrapping, filtering, electrical etc. Cultural: Writing, printing, Newspaper, currency etc. Food: Food wrapping, candy wrapping Coffee filter, tea bag etc. Raw Material Wood: Contain fibers from wood Agricultural residue: Fibers from straw, grass or other annual plants Recycled: Recycle or secondary Fiber
23
Paper Analysis Surface Treatment Coated: Coated with clay or other mineral. Uncoated: No coating Laminated: aluminum, poly etc Finish Fine/Course Machine Finished (MF)/Machine Glazed (MG) Glazed/Glossed
24
Paper Analysis Watermarks –Can tell age of document –Can tell manufacturer and location of store selling paper –Object to displace pulp during sheet formation –Area of paper thinner
25
Crime Target
26
Real or Counterfeit?
27
Copper to green color shift when tilt bill Watermark Security Thread Microprinting
28
Money Video Part 1 Part 2 Part 3 Part 4 Part 5
29
CHE 113 29 Questioned Documents (QD) Frank Abignale Jr., who successfully performed cons worth millions of dollars before his 19th birthday! He managed to get away with it by posing as a Pan American World Airways pilot, a Georgia doctor, and a Louisiana parish prosecutor. he become so skillful that the FBI turned to him to help in catching other check forgers!
31
Power of the Image
33
Lebanon bombed by Israel (Reuters) Fake or Real?
35
Iranian Missile Test Fake or Real?
38
Real or Fake?
39
Fake or Real?
41
Al-Ahram, the state-run newspaper in Egypt
42
“Brown Lady Ghost” 1936 Superimposing 2 Pics Involved time- consuming dark room tricks
43
History Photo Manipulators: –Stalin, Mao, Hilter, Mussolini, Castro and Brezhnev Why manipulate photos? –Make one look more heroic –Erase enemies –Propaganda –Media Stunts –Greed
44
What’s wrong here?
45
Look at light directions
47
Lighting Discrepancies
48
Clues of Fakes 1.Lighting –See differences in lighting direction amongst pieced parts –Look also for shadow discrepancies (size, shape and direction) 2.Eye Positions 3.Twinkles in eyes (Specular Highlights) –Look for consistency in the shape, color and location of these reflections
49
Specular Highlights
50
Twinkle Science Twinkles of American Idol Cast in Pic
51
Clues of Fake 4. Copy and Paste (Cloning) Bush Rally
52
Cloning in Movies
53
Clues of Fakes 5. Retouching (Modification of Image)
54
Reuters retouched this image from a meeting of the United Nations Security Council in 2005 The contrast of the notepad was adjusted to improve its readability
55
Camera Fingerprints Each type of digital camera has a light sensor that records an image in a set pixel pattern Can determine make and model of camera from photo Each camera produces individual “noise”
56
“Noise”
57
Clues of Fakes 6. Gross Logic Errors –Smoke blowing in two different directions from side by side smoke stacks –Army soldier wearing navy insignia –Watchmaker with pipe wrenches in work area
58
Digital Imagery and Law Police Chief David Harrison –Charged with possession of child porn –Cleared because he said State could not prove the images to be real! 2002 US Supreme Court ruled “virtual” or “computer generated” images of child porn constitutionally protected
59
Digital Imagery and Law 2005 Judge in Sydney, Australia threw out a speeding case when police had no proof to show that a traffic camera image was not doctored.
60
Red Light Ticket
61
Smartphone cameras and and GPS “Geotagging” iPhone or an Android phone.. you need to give the camera app access to the GPS data, so it can store it with your photo
62
Goes along with the image…
63
EXIF Reading Software
64
http://gdgtry.com/2010/08/finding-out- where-a-picture-was-taken-using-exif- info/comment-page-1/http://gdgtry.com/2010/08/finding-out- where-a-picture-was-taken-using-exif- info/comment-page-1/
65
EXIR Software http://exifdata.com/index.php
66
Voice Recognition In forensic science, voice recognition and linguistics may help to identify a speaker by their voice or speech patterns. Linguistics can also shed important light on the questioned interpretation of the meaning of a recorded confession or on the authenticity of verbal legal instructions. –Voice Identification - determining who is the speaker on a recording from among a group of possibilities –Voice Verification - determining if a recorded voice belongs to one particular person CHE 113 66
67
CHE 113 67 Voice Analysis Unique voice production to an individual is based on the physical process of speech itself…
68
Speech Production the brain, nervous system, lungs, larynx, tongue, jaw: –begins with the production of a positive air pressure in the lungs to generate a steady stream of air outward through the trachea (windpipe). –the thin tissues of the vocal cords in the larynx begin to rapidly vibrate causing alternating slight increases and decreases in air pressure –the faster the vibration, the higher the perceived pitch of the sound will be. CHE 113 68
69
Speech Production –the sound created in the larynx is modified as it passes through the remainder of the vocal tract by the jaw, lips, tongue, palate, nasal cavity and other organs modulating the sound waves into the audible patterns that we recognize as speech. –The subtle qualities of a sound, sometimes called timbre, depends largely upon the specific size and shape of the throat, mouth and nasal cavity CHE 113 69
70
Basic Concepts for Analyzing Voice Prints The sizes of the vocal cavities such as the throat, nasal and oral cavities and the shape, length and tension in an individual's vocal cords located in the larynx. –The vocal cavities are resonators, much like organ pipes, which reinforce some of the overtones produced by the vocal cords, which produce formats or voiceprint bars. –The likelihood that two people would have exactly the same size and configuration (is) very remote.
71
Basic Concepts for Analyzing Voice Prints The manner in which the "articulators" or muscles of speech are manipulated when an individual is talking. –The articulators include the lips, teeth, tongue, soft palate and jaw muscles, "whose controlled interplay produces intelligible speech...The likelihood that two persons could develop identical use patterns of their articulators also appears to be very remote.
72
Speech Production The probability that two people both have exactly the same physical make-up in their sound generating structures and employ the same speech articulations is extremely small. a method to measure and graphically display the differences of speech=sound spectrograph or voiceprint. CHE 113 72
73
Speech Production –A voiceprint displays three key components of speech in a single plot the vertical axis is used to display the different frequencies that make up the sound the horizontal axis shows time elapsed during the measurement the degree of darkness of the line at a particular point shows the intensity of that particular frequency at that one time CHE 113 73
74
Basic Concepts for Analyzing Voice Prints The caller on the 911 line was requesting an ambulance because, he said, he thought the woman in Apartment 204 was badly injured or perhaps dead. The caller did not identify himself. The case turned out -to be murder and later, when the police had a suspect, the district attorney used a spectrograph to check the suspect's voice with the tape-recorded voice of the 911 caller. Bingo!
75
Basic Concepts for Analyzing Voice Prints Quite often the only clue the police have is that 911 call, with a tape from a recorder of not good quality. And we've got to clean it up, take out the extraneous noise and then get a sample of the suspect's voice, for comparison. The suspect cannot refuse to provide a voice sample. Under the law he's required to do it. All you need is a court order. Then we make the match and go to court and testify against him." Steven Cain
76
Basic Concepts for Analyzing Voice Prints The process of identifying voices visually involves translating the wave patterns produced by the voice into a pictorial display called a spectrogram. The spectrogram serves as a permanent record of the words spoken and facilitates the visual comparison of similar words spoken by an unknown and known speaker's voice. The spectrogram serves as a permanent record of the words spoken and facilitates the visual comparison of similar words spoken by an unknown and known speaker's voice.
77
Basic Concepts for Analyzing Voice Prints Voiceprints contain dynamic qualities. For example, when you say good morning to your wife or husband early in the morning before you've had your first cup of coffee and then say it again later in the morning there will be some changes in the pitch of your voice and how you stress certain vowels. That's why we get several repetitions of a speaker's voice, saying the same thing, so we can find the range of variation.
78
Basic Concepts for Analyzing Voice Prints Is it possible for a person to "fool" a spectrograph?
79
Basic Concepts for Analyzing Voice Prints Is it possible for a person to "fool" a spectrograph? –Not really - You can disguise your voice, but you're not fooling the spectrograph; you're just not giving a parallel sample. If you distort your natural speaking voice to the point that you're not giving parallel voice samples you're really not comparing apples and apples. You're comparing apples and oranges. An experienced operator would notice this immediately. If I see this I won't stand for it and I will tell the court I will not accept such a sample and often they'll throw the defendant in jail for failing to comply with the district attorney's request for a natural, undisguised sample.
80
Basic Concepts for Analyzing Voice Prints It's essential that speech samples contain exactly the same words and phrases as those in the questioned sample, because only identical speech sounds are used for comparison. –the suspect should not be allowed to read the phrases from a transcript but should repeat each phrase after it is spoken by someone else. To avoid an unnatural response, the suspect should repeat the first phrase and proceed in the same manner with each successive phrase. –The limits generally are the quality of the evidence itself. It's like any other pattern-matching skill, such as handwriting. You have to have good samples."
81
CHE 113 81 Linguistics Linguistics is increasingly being used in legal settings understanding legal texts informing judicial processes interpreting the meaning of specific language in criminal cases. Applications may include the ability of certain suspects to understand their legal rights the specific wording of criminal confessions the meaning of certain statements made by participants during the commission of a crime the protection of the commercial rights of corporations for certain words and phrases
82
CHE 113 82 Linguistics Language plays an important role in aspects of the pre-trial criminal justice system including interrogating witnesses and suspects collecting statements obtaining confessions. This is especially important where bilingual or non-native speakers engage with the system since phrasing, tense, and voice may have subtly different meanings across languages. Linguists may also become involved in trademark disputes such as how trademarks and legally protected words may be translated into another language.
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.