-
- Investigative Photography and Electronic Imaging --
- Copyrighted by Ron Azzarello
-
-
- EVIDENCE ADMISSIBILITY
- Trial courts determine admissibility of photographic evidence. If you
- took the photographs, fots, you must lay the legal foundation. Judgment
- is based upon legal precedents that have considered some of the
- following points of law:
-
- - The object pictured must be material or relevant to the point at
- issue. Any fot that is no way instructive or of assistance to stress
or
- prove a point in issue may be withheld.
- - Fots must not appeal to the emotions or tend to prejudice the court
or
- jury. Trial judges have suppressed the introduction of fots showing
a
- savagely mutilated body or grizzly subjects. It wasn't that long ago
- that color proofs were considered prejudicial.
- - Is your submission an accurate representation of the scene? The object
- represented must be free from distortion and cannot be misrepresented.
- Fots obtained improperly, by tilting the camera, capturing an image
from
- an incorrect angle or point of view, present biased distortions and
- should be a greater concern than an image digitally manipulated to
- reflect true colors. Insufficient light or over-exposed proofs effect
- quality and jeopardizes admissibility as evidence, too. You must
- understand photo-technology as a professional investigator/witness.
-
- CRIME SCENE IMAGING
- If law enforcement, LE, uses digital technology to get a better
- understanding of the crime, why shouldn't you? How crimes were
- committed, the setting, the manner particular evidence is related to
- defendant or the crime is not just relevant, it is necessary. Fots
are
- obtained of evidence or conditions to illustrate alternative fact
- issues. Criminal defense investigators take reference fots to challenge
- the States' evidence, to brief lawyers, and to keep from making
- redundant field trips.
-
- LE has gone digital and so have many career PI's. Check-out Adobe
- Photoshop 4.0 <http://www.adobe.com>
to digitally manipulate, through
- image-stiching Live <http://www.livepicture.com>
Picture "PhotoVista"
- software, 360 degree panoramas of crime and personal injury scenes
and
- opposing defensive challenges. If you are not helping clients, lawyers,
- judges, and juries get a better impression of the big picture, you
are
- missing an income opportunity.
-
- Ponder "More Hits" Protection Plus, 10027 South Tacoma Way,
Suite G-1,
- Tacoma, WA 98499, <http://www.coldwater.com/>
They may have a digital
- image tracking and processing solution to preserve evidence integrity
- that has been accepted in court. They automatically calibrate for true
- 1:1 imaging, enhancement history, and it is compatible with other image
- enhancement systems.
-
- PERSONAL INJURY IMAGING - Vehicle Collision
- In the early 1970's, PI's photographed the depth of maximum crush to
- determine a change in velocity (delta v) to calculate speed and the
- force of impact to occupants. Limitations arose, so better arithmetic
- modeling of collisions created a uniform descriptive report of vehicle
- damage. VDI, Vehicle Deformation Index, was replaced by the current
and
- more complete, CDC, Collision Deformation Classification. Massive
- injuries and high policy limits, demand PMP, Photo- grammetric Mapping
- Protocol.
-
- Obtaining a working knowledge of the professional standards needed
for
- serious investigative projects is important to your career growth.
You
- must first understand and then master reasonable goals with professional
- tools and equipment. The camera you use must be of exceptional quality
- and versatility, but not necessarily new; just rugged. Quality lenses
- are better investments than cameras. Camera bodies that interchange
- lenses and digital imaging cassettes instead of film is what PI's will
- soon utilize.
-
- PHOTO/VIDEO -- Review
- The shutter speed controls how long the shutter remains open and lets
- reflected light onto the film. Long lenses magnify camera shake, so
to
- work from a distance you must have a fast exposure or the fot will
be
- blurred, even if the subject is standing still. No matter how good
your
- equipment, you still must have some amount of light to reach the film,
- in order to get a decent exposure.
-
- The aperture chokes the amount of light coming through the lens. A
fully
- choked lens only sees through the center of the lens. However, running
- a lens wide open reduces the depth of field. Each click of the shutter
- speed control is equal to one click of the aperture ring. Every time
you
- move either control one "stop", or click, you have doubled
or halved the
- total amount of light getting to the film.
-
- When handling long or mirror lenses, double or quadruple the speed
of
- the film by dialing in the higher setting and have it push processed.
- The lab will leave the film in the developer a longer time. The image
- quality changes a little, but it works. Each doubling of film speed
buys
- one extra stop up of either aperture or shutter speed.
-
- FILM v DIGITAL
- I am going to assume you shoot at a professional level with consistent
- quality. Master basic photo/videography skills and you can enter the
- realm of capturing a quality image with more complex digital cameras
and
- get images introduced into evidence -- painlessly.
-
- To understand how digital cameras record images, get to know, up front,
- how much data must be captured by a digital camera for the intended
- output requirements. A 35mm image on fine grain film can produce a
- gigantic file when scanned with a high-relolution, high-quality scanner.
-
- There are two methods by which a digital camera captures data. One
is to
- capture the image instantly using a two-dimensional charge coupled
- device, CCD, sensor called an "area array." This CCD is like
a piece of
- film that receives an exposure and records all the data in an instant.
- The second method is to "scan" the image using a single row
of CCD
- sensors. This kind of capture can take several minutes to record the
- scene, and forbids any movement of the subject being captured.
- Obviously, not for PI purposes, we usually do not ask subjects to,
"Say
- cheese."
-
- Area array CCD cameras have two disadvantages: First, the file sizes
- they produce are limited and the cost is based on the maximum resolution
- they can provide. It is expensive to produce a high-resolution,
- two-dimensional CCD. Another disadvantage is that two-dimensional CCDs
- are monochromatic, in order to capture a color image instantly, the
CCD
- must have a matrix of colored filters on or in front of it. Software
is
- also required to interpolate the data and create a color file. A few
- camera manufactures use three separate CCDs and a beam splitter to
- expose each CCD through red, green, and blue filters. This method
- results in true, non-interpolated color, but increases the camera cost
- to far more than a CCD capture camera of similar resolution.
-
- How large a file will you need? A camera that can capture a 48 MB file
- at 4,096x4,096 pixels costs a whopping $50,000. To rich for this
- investigator to justify, consider:
- - Is it cost effective to shoot with a digital camera?
- - Will the camera capture a sufficient file for my output needs?
- - Will the inevitable color artifacts present a problem?
- - Do I want, a camera-back that fits my conventional camera, or be
- self-contained?
-
- Not having to wait hours or days for film processing is an advantage;
- cheaper, too. Silver-based film and the processing required to develop
- an image are environmentally unfriendly has caused many governmental
- agencies and large companies to go digital. More important, you retail
- full custody and control of the image and can not blame the lab for
- mistakes.
-
- There is another issue, the quality of the digital capture. Kodachrome
- has a unique look that differs vastly from Fujichrome, and many PI's
use
- a film based on its particular qualities to improperly prejudice results
- in client's favor. Since these characteristics can cause problems with
- color fidelity and possibly taint admissibility, wouldn't it be easier
- to achieve accurate color reproductions by avoiding film altogether?
-
- Can you justify the cost of an expensive camera system in your business;
- will you continue to make a profit? You can always rent, but you
- probable would not have the software nor know how to use either
- properly. One clear fact remains, the quality of the files captured
with
- the right digital camera system far surpasses that of film, while
- providing significant advantages in the creation of images.
-
- Analyze the technology for a moment to compare cameras and identify
your
- budget. Resolution is a crucial specification when evaluating a digital
- camera. The number of pixels a camera can create greatly affects the
- quality of the printed output. The more pixels a camera provides, the
- larger the file that can be output with acceptable results. Most desktop
- models produce at least a 640x480 pixel image, up to about 1,280x1,024.
-
- The number of pixels you end up with is a most important factor in
the
- purchase of a digital camera. Some cameras use less than the full
- resolution of the CCD to create smaller files. Digital camera
- manufacturer's information about resolution is increasingly difficult
to
- decipher. Knowing the exact number of pixels the CCD provides along
each
- axis allows you to determine what size print can be produced. It also
- provides data about the camera's aspect ratio, because it provides
the
- width and height of the CCD.
-
- Most CCD's are manufactured with extra pixels placed on the edge of
the
- sensor for providing color balance, luminance, and image processing.
The
- total area of the CCD sensors is called the chip resolution area. The
- actual number of pixels that capture the image is the figure you need
to
- ID. Even when given the total image resolution, you may not be getting
- the real facts. Some cameras use rectangular pixels and then
- interpolate, via software, to provide the rest of the information needed
- to create the image. PCI, pixels per inch is different than DPI.
-
- If you have a camera that takes pictures without film, you need a place
- to store images. It would be counterproductive to run out of storage
- space in the middle of a project. There are cameras being sold with
no
- provisions for removable media. While claims are made that a camera
- stores hundreds of images, rest assured files are undergoing a lot
of
- nasty compression that doesn't do much for image quality.
-
- The fist digital cameras had PCMCIA cards. Type I and II cards are
flash
- memory cards with no moving parts. Type III cards are small hard drives
- and are the standard in high-end digital cameras. These cards can be
- inserted into standard PCMCIA card readers found on many laptop and
some
- desktop computers. CompactFlash memory is smaller, but can be adapted
to
- fit PCMCIA readers. A third kind of memory, SmartMedia, is smaller,
- about the size of a postage stamp and it can be adapted to PCMCIA
- readers. Don't forget the cost of these memory adapters.
-
- Standard PCMCIA memory should remain your choice because they are
- rugged, Type I and II come in sizes from 5MB to 80 MB. Type III cards
- max out at 520MB, which is handy on extended projects. CompactFlash
can
- be had with as high as 45MB, but SmartMedia cards are easy to lose
or
- damage and only range in size to 8MB.
-
- If you upgrade your camera to one using different media, your existing
- collection of cards, like lenses, may not be compatible with the new
- camera. Some save files onto standard 3.5 inch floppy disks, but that
is
- a most inappropriate medium. While floppies are inexpensive, they are
- slow, limited in the amount of data they hold, and they are extremely
- unreliable compared to flash memory. If the camera is based on an
- existing conventional camera body, such as Canon, Minolta, or Nikon,
- virtually all the interchangeable lenses manufactured for that camera
- will fit.
-
- Many cameras offer digital zoom, which merely interpolates the data
from
- a smaller area of the CCD. It is much better to do this with software.
- True interchangeable optical zoom lenses are much more important for
- probative applications. Video output is an attractive feature on a
- digital camera. It allows you to view your images on a standard TV
or
- computer monitor, turning a camera into a very nice presentation device.
-
- The software provided with a digital camera is an important
- consideration. Most camera companies supply software needed to download
- their images. Some cameras ship with software that only display previews
- or thumbnails of the images captured, allowing the user to acquire
them
- into some kind of file format, such as JPEG or TIFF. Others package
- image editing software, such as Adobe PhotoDelux.
-
- KODAK DCS 520/CANON EOS D2000
- Eastman Kodak and Canon released the same version of a prosumer digital
- camera that incorporates Kodak's digital capture technology with Canon
- lenses. This is one of the most impressive single capture digital
- cameras to be found. Built onto a Canon EOS body, the DCS 520 can
- produce a 5.73MB file (1,736x1,160 pixels) while capturing up to 12
- continuous frames at 3.5 images per second. The viewfinder is designed
- to show a full image that is WYSIWYG, because the CCD is smaller than
a
- 35mm frame, however, lenses do not produce a longer focal length effect.
-
- The camera stores images on a type III PCMCIA drive, allowing the user
- to store 199 images on a 340MB card. The DCS 520 has an ISO equivalent
- from 200 to 1,600. Since the body is based on a Canon EOS, all EOS
- lenses can be used, and all the functions EOS users are accustomed
to
- are available, such as TTL flash and exposure compensation. A removable
- NiCad battery provides power for 300 shots per charge. On the back
of
- the camera is an LCD display with unique features. Like most digital
- cameras, the LCD displays images captured while allowing you to toggle
- through all the images previously written to disk.
-
- Available features include time/date stamp, control over the PCMCIA
card
- (formatting), and tagging of specific images to aid in fast downloading
- of selected images from the PC card. There is a microphone on the camera
- to get you into trouble if you misspeak. Other features include an
auto
- white balance sensor mounted on the body, with four manual settings
for
- daylight or flash, and tungsten or fluorescent conditions that would