- Method was based on two premises:

- the dimensions of the human-bone system remain unchanged from age 20.

- No two individuals have the same measurements at the 11 different locations that were chose.

Anthropometry

system began in France around 1883 and was in wide use throughout the world until 1903.

- it was proved its worth in identifying and helping to convict persons with prior conviction records.

anthropometry history

- review particular details

- provide evidence for forensic comparison purposes

- document an injury has occured

- convey information in courtroom

Purposes of crime scene photography

- must be a fair and accurate representation of the scene it depicts

- must be relevant to the matter at hand

- must be properly authenticated (chain of custody)

3 points of qualifications of photos as evidence

1. take long range shots of the scene

2. move to mid-range shots to show the context of evidence

3. take close up shots of individual pieces of evidence

4. try to change perspective of photographs

5. provide placards and scales

documenting a crime scene

- fill the frame

-maximize depth of field

- keep lens perpendicular to subject

cardinal rules of crime scene photography

- capture a clear, accurate, and complete record of the scene and evidence

- maintain proper focus, exposure, and perspective

rules of investigative photography

- alllow the photographer to answer questions about his/her work while giving testimony

Purpose of photo log

What info does photo log contain?

- case number

- data and time of photograph

- location

- descriptions of subject

- camera settings (ISO, shutter speed, f-stop)

- marker or label placed in a photograph to link the image to a specific case

- usually includes case number, photographers name, and date

case identifier tag

- intensity of a point-light-source is inversely proportional to the square of the distance to the source

- as the distance increases, the light intensity decreases rapidly

inverse-square law how it relates to intensity

- integrated into camera

-least powerful

- red eye problems

built-in flash

- separate unit that can be mounted on the camera or positioned independently

- generally more powerful

- offer more control over lighting

external flash

timing of the flash firing to coincide with the camera's shutter opening

flash synchronization

- used to add light to shadowed areas of a subject

- often used in bright daylight to reduce harsh shadows

fill flash

- involved aiming the flash at a reflective surface (like a ceiling or wall) to diffuse the light and create softer illumination on the subject

bounce flash

- softened light achieved by placing a diffuser over the flash to scatter the light

diffused flash

- used in low-light conditions

- a light source is moved during a long exposure to illuminate different parts of the scene

painting with light

- strap should be around neck

- lens cap on when not in use

- camera should be stores in a cool/dry place

handling the camera

Why are tripods needed?

- stabilize the camera, especially during long exposures or macrophotography

- prevent camera shake

- ensure sharp images

- camera is positioned at a 90º angle perpendicular to the subject

- the closer the camera is to the subject, the more distortion arises

examination quality photographs using a tripod

scientific working group- imaging technology

SWGIT

documentation images used to record a time, place, or event

- general crime scene or investigative images, including images of physical evidence collected at the crime scene

- surveillance images

- autopsy images

- mug shots

- documentation of items of evidence

category 1 images

evidentiary images used for scientific analysis and comparison

- latent prints

- bloodstain pattern images

- questioned documents

- tool mark images

- gunshot residue images

- impression evidence

other images subject to analysis

category 2

- fundamental units of digital information

- represents binary values that make up a digital image

bits of data

data that provides information about other data

- includes details about the image such as camera setting, date, and time

- important for verifying the authenticity and integrity of the image

metadata

Whata are the best practices in digital image enhancement?

- start with the best possible image

- preserve the original image

-make enhancements to a copy of the original image

- be able to authenticate both the original and enhanced images to prove their authenticity and integrity

- maintain enhancement history for digitally processed images

- follow standard operating procedure that defines the digital imaging process from the point a digital image is acquired until the image is presented in courtroom

- use JPG file format

- detaailed enhancement history not required

- agency can specify in its SOP precisely what image editing functions may be used to enhance image

enhancement category 1

- use noncompressed file format (RAW or TIF)

- detailed enhancement history must be maintained for all images

- basic enhancement techniques must be documented becasue they can affect the results when used with advanced enhancement techniques on same digital image

enhancement category 2

the range of tones that a camera can capture, from the darkest shadow to the brightest highlights

dynamic range

- occurs when the image data exceeds the maximum or min recordable values

- results in loss of detail in highlights or shadows

clipping

- Fast Fourier Transform

- algorithm used to decompose and image into its frequency components

- useful for certain types of image processing

FFT

- repetitive patterns generate unique energy spikes or signatures that appear in different locations in the frequency domain

- these spikes can be removed without altering the fingerprint data

ex: dust shoe print, subtract fabric pattern, and invert and expand contrast

removing background from images

- records the sequence of edits made to an image, allowing users to undo changes or review the editing process

- crucial in forensic image enhancement as it provides a record of all modifications, ensuring transparency and admissibility in court

history log of enhanced images

how to start/view history log?

1. go to edit > history log

2. click to check history log box, turning it on, and select following options:

- save log items to: metadata

- edit log items: detailed

- graphical representation of the tonal distribution in an image

- used to assess exposure and adjust

histogram analysis

look at histogram pictures

- used to achieve close-up, highly detailed photographs

- diopters (close up filter)

- extension tubes

- bellows

- reversing rings

- macro lenses

macrophotography accessories

- control light and eliminate shadows at close distances

- ring-flash

- macro-flash

- flash direction

- flash intensity

- reflection

macrophotography lighting

- the ratio of the size of an object on the image sensor to its actual size

- the higher range of magnification

- the more difficult the project

- the less the depth of field

- the more light is necessary

magnification

-meaning it can be easily be degraded or even washed away

transient evidence

- important for reproducing crime scenes especially in the courtroom

- mapping out quadrants to create a scaled documentation of bloodstaining

- best for flat surfaces

quadrant mapping

- open aperture to decrease depth of field

- consider adding contrasting background to make the staining more visible

-

photographing blood on glass

- take long, mid, and close-up photos of individual

- establish locations of stains and if suspect or victim

photographing bloodstains on a person

- use different lighting techniques like infrared lighting or color filters attached to the lens of the camera

- use pointers

photographing blood on clothes

What does luminol and BlueStar react to?

react with iron found in blood (hemoglobin) which causes the fluoresence

What does luminol and Bluestar useful?

- easier to find hidden or cleaned-up bloodstains

Explain why maintaining the integrity of images is crucial in forensic photography

to ensure admissibility in court and an alteration that isnt documented can compromise the reliability and validity of evidence

Three common mistakes that can compromise admissibility of forensic photography?

- failure to maintain photo log

- improper chain of custody

- unauthorized image manipulation

Discuss ethical consideration a photographer must keep in mind?

objectivity, accuracy, avoiding sensationalism, and repecting privacy

refers to the ability of an item of evidence to assist in the exploration of an issue

probative value

evidence excited the jury or produced feelings of sympothy and/or outrage which could affect their decision

prejudicial effect