Guidelines
for Field Applications of Imaging Technologies in the Criminal Justice
System
Scientific
Working Group on Imaging Technologies (SWGIT)
Version 2.3, December 6, 2001
Message
from the Chair
Introduction.......Advantages
and Disadvantages of Major Image Capture Technologies in Field Applications.......Silver-Based
Film Cameras.......Discussion.......Instant
Print Cameras.......Digital Cameras.......Video
Cameras.......Hybrid Imaging Systems.......Guidelines
for Standard Operating Procedures (SOPs)
Introduction
The purpose
of this document is to:
- Provide specific
recommendations and guidelines for the use of imaging technologies
in law enforcement field applications.
- Describe
the advantages and disadvantages of silver-based film cameras,
instant photography cameras, digital still cameras, video cameras,
and hybrid imaging systems in law enforcement field applications.
- Provide general
guidelines for preparing agency-specific imaging technologies
standard operating procedures (SOPs) for law enforcement field
applications.
- Provide imaging
equipment recommendations.
This document
addresses the photographic documentation of events or subjects that
are not in a controlled environment (e.g., forensic laboratory or
studio).
The field applications
addressed in this document include the following imaging:
- General
crime scene photography
- First responder
(FR) photography
- Surveillance
photography
- Tactical
surveys
- Hazardous
materials (HAZMAT) crime scene photography
- Aerial
photography
- Accident
scenes
- Arson
photography
- Autopsy
photography
- Bomb
scene photography
- Mass
disaster photography
- Search
warrant photography
- Gang-related
graffiti photography (FR)
- Field
mug shots and tattoos (FR)
- Victim
photography
Advantages
and Disadvantages of Major Image Capture Technologies in Field Applications
The selection
of an acquisition device (camera) is driven by the purpose and requirements
of the end product. Therefore, the final use of the image should
determine the choice of the camera.
The recommendations
for primary and secondary image capture devices are dependent on
current technology and may change subject to changes in technology.
These recommendations are made based on the practical experience
of the SWGIT membership in the acquisition and analysis of the images
discussed herein. Agencies should decide what technologies are best
suited to meet the requirements of their mission-specific tasks.
As long as an agency can demonstrate and document that its choice
of technologies is adequate to meet its anticipated needs, the agency
should not feel required to adhere to the SWGIT recommendations.
Silver-Based
Film Cameras
It is strongly
recommended that a camera capable of manual override, with interchangeable
lenses, off-camera flash, and a tripod mount be used as the primary
capture device along with conventional silver-based film in 35 mm
format or larger as the primary capture media for evidentiary photography/imaging.
Advantages
of silver-based film cameras in field applications:
- Highest resolution
of available image capture options
- Highest dynamic
range of available image capture options
- Best color
range of available image capture options
- Most flexibility
of currently available image options
- Most durable
storage medium
- More readily
available in the field than video or digital storage media
Disadvantages
of silver-based film cameras in field applications:
- Need for
separate processing/printing facilities
- Relatively
long processing time
- Environmental
hazards generated by processing byproducts
- Preprocessing
fragility (i.e., temperature, humidity, x-ray effects, expiration)
- No means
of immediate image evaluation (with the exception of instant film)
Discussion
Resolution:
The best measure of resolution is the evaluation of output imagery,
which is the product of a series of steps. However, since this document
is devoted to field applications, the following discussion is restricted
to camera evaluation only. Users should verify resolution by visually
examining images of test targets in their specific environments.
SWGIT uses the
following definitions of resolution: "Measure of capability
to delineate picture detail;" and "The ability of a photographic
system to record fine detail." These definitions are a subset
of those found in ANSI/A Technical Report TR26-1993: Resolution
as it Relates to Photographic and Electronic Imaging.
|
Figure
1 Conventional Film Resolution in Terms
of Line Pairs per Millimeter (Lp/Mm) or Lines per Millimeter
Click to enlarge image. |
Traditionally,
film manufacturers measure resolution in terms of line pairs per
millimeter (LP/mm) or lines per millimeter. Figure 1 illustrates
how a line pair consists of a black line and an adjacent white line.
Lines per millimeter refers to each line (black or white), thus
there are always twice as many lines as there are line pairs over
a given distance.
Manufacturers
of digital cameras frequently describe image size in terms of number
of pixels. As stated in ANSI/A TR26-1993, "There is a common
practice of referring to digital resolution as simply the total
number of pixels within a frame or field, or alternately as the
number of pixels in the horizontal and vertical directions. Alone,
this information is useful to indicate the amount of data that can
be handled in a single field at a given moment, but tells nothing
about the unit's ability to resolve spatial information." (Note
that the words frame and field in the quote refer to a photographic
field of view. These should not be confused with the terms used
in video technology.)
The ability
to resolve spatial information can only be determined by testing
a specific imaging system. In order to compare technologies, the
total information that can be represented in the sensor is discussed.
This constitutes an upper limit to the actual achievable resolution.
|
Figure
2 Relating Line Pairs per Frame to Pixels
per Frame under theoretically ideal conditions. Each Line Pair
corresponds to two-pixel columns. Click
to enlarge image. |
It
is possible to directly compare the maximum amount of information
that can be represented by any two sensors by comparing the total
number of pixels per frame. To compare film to the sensors in digital
cameras (CCD/CMOS), it is necessary to relate line pairs per frame
to pixels per frame. Figure 2 illustrates how, under ideal conditions,
two pixel columns (or rows) represent one line pair.
Common film
types encountered in law enforcement field applications have optimal
resolutions in the range of 40 - 160 line pairs per millimeter.
Black and white films typically used at crime scenes have resolutions
at the upper end of this range. Color films used at crime scenes
have resolutions at the lower end of this range.
A single frame
of 35 mm ISO 200 color film is 36 mm wide by 24 mm high. With a
resolution of 50 line pairs per millimeter, such a frame can resolve
the following:
36mm x 50
LP/mm = 1800 line pairs horizontally
and
24mm x 50 LP/mm = 1200 line pairs vertically.
The equivalent
number of pixels in a single frame is then calculated:
1800 line
pairs x 2 pixels/line pair = 3600 pixels horizontally
and
1200 line pairs x 2 pixels/line pair = 2400 pixels vertically.
This represents
a total of 3600 x 2400 = 8,640,000 pixels.
A digital camera
with a detector that is 3040 x 2008 pixels in size contains more
than six million (6,104,320) pixels. This is referred to as a 6-megapixel
camera.
There is a tradeoff
between the field of view and the resolution that can be represented
by a sensor. If the field of view is held constant, then the resolution
will vary with the number of pixels. If resolution is held constant,
then the field of view will vary with the number of pixels.
|
Figure
3 Comparison of Field of View 35 mm ISO 200 Color Film
versus 6-Megapixel CCD for Constant Resolution Click
to enlarge image. |
If the field
of view is held identical for both sensors above (35 mm ISO 200
color film and a 6-megapixel CCD), the film, with 40 percent more
pixels than the CCD (8.64 million versus 6.1 million), will provide
an improvement in resolution of approximately 20 percent.
Alternatively,
if the resolution is held constant for both sensors, the film will
cover a field of view that is 40 percent larger than the CCD, as
illustrated by Figure 3.
The resolution
that can be achieved in a digital camera will be lower than the
upper limit (ideal conditions) discussed above. Some research has
found that it takes approximately four pixels to capture and reproduce
a line pair under test conditions, instead of the representation
by two pixels. Using this standard, the pixel resolution of film
is effectively doubled. The practical result of using four pixels
per line pair leads to the comparisons in Table
1 and Figure 4.
NOTE: Discussing
the resolution of video systems is beyond the scope of this document.
SWGIT will address issues relating to video resolution in future
documents.
To
compare the size of images generated from each of these sensors,
a common output resolution must be defined. A conservative divisor
of 200 pixels per inch (ppi) is generally used to determine the
output size. Table 2 lists the
size of the images generated using the sensor resolutions in Table
1.
In the above
discussion, only film and digital sensors were considered. In reality,
an image is captured and later displayed using an entire system
in which several factors may affect the resolution of the particular
image. The quality of the optics (lens or lenses) used to focus
the image on the sensor plays an extremely important role and may
greatly limit the overall resolution of the system. Also, differences
in display methods may limit or enhance the perceived resolution.
CCD sensors
often achieve color acquisition by using one sensor array with pixel
cells of alternating color sensitivity. Thus the overall resolution
of the image will be less than the specified number of pixels on
the sensor. One way to ameliorate this situation is to use a camera
that contains three CCDs instead of one. This allows one to have
a separate CCD for each primary color, red, green, and blue. Therefore,
for the same specified number of pixels at the sensor, a three-CCD
camera will provide higher resolution than a single-CCD camera.
Two other factors
that can effect resolution include the contrast in the scene and
noise. In this context, contrast refers to the apparent difference
between the brightest and darkest parts of the scene. As contrast
increases, resolution increases. Noise refers to random variations
that limit the fidelity of detection and reproduction systems, such
as the granularity of photographic images. As noise increases, resolution
decreases. Identifying the specific effects of these factors on
each of the sensors discussed above is beyond the scope of this
document.
Dynamic Range:
The difference between the brightest highlight and darkest value
that a sensor (film or CCD) can detect and record in a single image.
Negative film provides two to four f-stops more than most digital
cameras. This increased dynamic range allows capture of both shadow
and highlight details in a single frame of film. These same details
might require several different images (at different capture settings)
when recorded with a digital camera.
Color Range:
The range of colors that can be detected by a sensor compared to
normal human vision. Negative film has a color range that is superior
to CCDs.
Flexibility:
The selection of speeds and types of film available. Silver-based
photography provides a wider selection of film speeds and types
than digital cameras. Film can be selected for specific applications
in the field, and the film speed or type can be changed on-site
to meet specific needs.
Instant
Print Cameras
Advantages
of instant print cameras in field applications:
- Immediacy
of the final image (instant viewing/verification of image)
- Operational
security (all processing is in-house)
Disadvantages
of instant print cameras in field applications:
- Limited resolution
of image
- Production
of copies requires multiple steps and can reduce image quality
- High cost
per image
- Manual override,
interchangeable lenses, or off-axis flash rarely offered
Digital
Cameras
Advantages
of digital cameras in field applications:
- Immediacy
of the final image (instant viewing/verification of image)
- Ability to
transmit and disseminate image with minimum of intermediate steps
- On-site image
management
- Potential
for on-site printing
- Operational
security (all processing is in-house)
- Environmental
impact more friendly than film
Disadvantages
of digital cameras in field applications:
- Battery or
power supplies:
1. Environmental impact
2. Availability
3. Power conversion
- Limited availability
of storage media (available only from specialized stores)
- Storage media
subject to damage from electromagnetic fields
- Image acquisition
subject to electromagnetic interference
- Hardware
and software can be proprietary and incompatible among manufacturers
- Legacy file
problem (evolution of technology, including hardware and software,
may impact ability to access archived images over time)
Video
Cameras
NOTE: Fixed
camera video surveillance systems are not addressed in this document.
They will be addressed in future SWGIT documents.
Advantages
of video cameras in field applications:
- Real-time
motion record capability
- Immediacy
of image (instant viewing/verification of image)
- Ability to
transmit and disseminate image with minimum of intermediate steps
- More environmentally
friendly than film
- Ability to
print in the field
- Ability to
synchronize and capture audio
Disadvantages
of video cameras in field applications:
- Battery or
power supplies:
1. Environmental impact
2. Availability
3. Power conversion
- Some high-quality
storage media available only from specialized stores
- Storage media
subject to damage from electromagnetic fields
- Image acquisition
highly subject to electromagnetic interference
- Resolution
of still images is less than that of digital or silver-based capture
media
- Limited color
fidelity (VHS and 8 mm formats, in particular)
- Reduced media
lifetime
- Automatic
compression in some formats
- Weight and
portability of equipment may be an issue
Notes
on video formats:
- VHS and 8
mm formats are the most commonly available formats but have the
worst signal-to-noise ratio of any video format (greatest amount
of noise).
- Super VHS
and Hi-8 formats are the second most commonly available formats
and have somewhat better signal-to-noise ratio than VHS.
- Beta SP and
MII formats are professional-broadcast quality and are the best
analog format available.
- Digital video
quality varies, the high end is better than analog systems.
Hybrid Imaging Systems
A hybrid system
is the combination of silver-based photography and digital imaging
technology that typically involves the conversion of silver-based
film or print images to digital images through the use of scanners.
Hybrid imaging systems incorporate some of the benefits of both
film and digital image technologies and are recommended for those
agencies and organizations seeking to add digital imaging technologies
to their photographic resources.
Advantages
of hybrid imaging systems in field applications:
- Shortens
darkroom time for producing prints
- Maintains
high-quality original film images
- Offers flexibility
of digital image processing
- Enables easy
electronic transmission of images
- Enables image
analysis
- Simplifies
case file management
- Enables the
use of a variety of output devices
- Permits the
production of copies from prints generated through instant photography
Disadvantages
of hybrid imaging systems in field applications:
- Separates
processing/printing facilities
- Has a relatively
long processing time
- Generates
environmentally hazardous byproducts
- Demonstrates
a preprocessing fragility (i.e., temperature, humidity, x-ray
effects, expiration)
- Has no means
of immediate image evaluation (with the exception of instant film)
Guidelines
for Standard Operating Procedures (SOPs)
General
Guidelines for a Crime Scene Photography SOP
TITLE: Crime
Scene Photography SOP
PURPOSE: To
permanently document, by qualified personnel, evidence and other
details at a crime scene for future reference
NOTE: Crime
scene photography generally requires the ability to:
- Record information
that crime scene personnel may not know was important at the time
the images were captured
- Deal with
varying lighting and physical conditions
- Accurately
represent the details and colors in a scene
- Get close-up
and wide-angle images with accurate spatial relationships
Crime scene
photography is usually a time-limited activity when there is only
one opportunity to correctly complete the task. Depending on the
nature of the crime or incident, conditions at a crime scene may
dictate the selection and use of differing equipment and techniques.
EQUIPMENT: (Image
Capture Devices)
- Silver-based
film cameras are recommended for use as the primary image capture
device. The minimum recommendation is a 35 mm (SLR) camera capable
of manual override, interchangeable lenses, off-camera flash,
and tripod mount
- Digital still
imaging can be used in a supplementary capacity (see Digital
Cameras). Digital still imaging can be used as the primary
image capture device when the performance of the equipment can
be shown to meet anticipated needs
- Video imaging
can be used in a supplementary capacity. S-VHS, Hi-8, or better-quality
formats are recommended. It is suggested that cameras have the
ability to incorporate external/wireless audio, the ability to
disable on-camera audio, and incorporate/disable in-camera image
stabilization (See Video Cameras)
- Other standard
photographic equipment as necessary
PROCEDURES:
Agencies should follow agency-specific step-by-step instructions
for documenting crime scene evidence.
CALIBRATION:
If necessary, agencies should develop procedures specific to their
needs.
CALCULATIONS:
If necessary, agencies should develop procedures specific to their
needs.
LIMITATIONS:
See Advantages and Disadvantages of Major
Image Capture Technologies in Field Applications
SAFETY: Agencies
should develop procedures specific to their needs.
REFERENCES:
Agencies should refer to agency-specific documentation and manufacturers'
manuals.
General
Guidelines for a First Responder (A) SOP
The only images
taken are those taken by the first responding officer(s).
TITLE: First
Responder Photography SOP
PURPOSE: To
document conditions found at an incident by the first law enforcement
official(s) on the scene where a crime scene photography unit or
specialist will not be requested
NOTE: Examples
may include: domestic violence incidents, traffic accidents, minor
property crimes, and other incidents as defined by agency-specific
policies. Photography generally is not the first responder's primary
responsibility, and the first responder may have only a minimal
amount of photography training.
EQUIPMENT: (Image
Capture Devices)
- Silver-based
media film camera. Minimum recommendation is a 35 mm camera with
flash and close-up capability
- Digital still
imaging. The minimum recommendation is for a camera with more
than 1600 x 1200 pixels (>2 megapixels), on-camera viewer,
close-up capability, flash, and removable storage media
- Video imaging
can be used in a supplementary capacity. S-VHS, Hi-8, or better-quality
formats are recommended. It is suggested that cameras have the
ability to incorporate external/wireless audio, disable on-camera
audio, and incorporate/disable in-camera image stabilization (See
Video Cameras)
- Other standard
photographic equipment as necessary
PROCEDURES:
Agencies should follow agency-specific step-by-step instructions
for documenting crime scenes.
NOTE: Images
from separate incidents should be clearly delineated through a change
of storage media or through proper documentation.
CALIBRATION:
If necessary, agencies should develop procedures specific to their
needs.
CALCULATIONS:
If necessary, agencies should develop procedures specific to their
needs.
LIMITATIONS:
Successful capture of close-up images will require adhering to manufacturers'
specifications. Images captured digitally typically have a limited
enlargement capability that is less than those captured using 35
mm film (See Advantages and Disadvantages
of Major Image Capture Technologies in Field Applications).
Successful capture of images also requires utilization of fresh
media (e.g., film that is not past expiration and has been stored
properly) and well-maintained equipment.
SAFETY: Agencies
should develop procedures specific to their needs.
REFERENCES:
Agencies should refer to agency-specific documentation and manufacturers'
manuals.
General
Guidelines for a First Responder (B) SOP
Images taken
by the first responding officer(s) prior to arrival of a crime scene
photographer.
TITLE: First
Responder Photography SOP
PURPOSE: To
document conditions found at an incident by the first law enforcement
official(s) on the scene prior to the arrival of a crime scene photographer
NOTE: This guideline
is directed toward documenting transient conditions that might be
lost prior to the arrival of crime scene photographers. Examples
include situations in which evidence must or might be moved, lost,
or altered. Photography generally is not the first responder's primary
responsibility, and the first responder may have only a minimal
amount of photography training.
EQUIPMENT: (Image
Capture Devices)
- Silver-based
media film camera. The minimum recommendation is 35 mm camera
with flash, close-up capability
- Digital still
imaging. The minimum recommendation is for a camera with more
than 1600x1200 pixels (>2 megapixels), on-camera viewer, close-up
capability, flash, and removable storage media
- Video imaging
can be used in a supplementary capacity. S-VHS, Hi-8, or better-quality
formats are recommended. It is suggested that cameras have the
ability to incorporate external/wireless audio, disable on-camera
audio, and incorporate/disable in-camera image stabilization (See
Video Cameras)
- Other standard
photographic equipment as necessary
PROCEDURES:
Agencies should follow agency-specific step-by-step instructions
for documenting crime scenes.
NOTE: Images
from separate incidents should be clearly delineated through a change
of storage media or proper documentation.
CALIBRATION:
If necessary, agencies should develop procedures specific to their
needs.
CALCULATIONS:
If necessary, agencies should develop procedures specific to their
needs.
LIMITATIONS:
The successful capture of close-up images will require adhering
to manufacturers' specifications. Images captured digitally or with
video typically have a limited enlargement capability that is less
than those captured using 35 mm film (See Advantages
and Disadvantages of Major Image Capture Technologies in Field Applications).
Successful capture of images also requires using fresh media (e.g.,
film that is not past expiration and has been stored properly or
new, unused videotapes) and well-maintained equipment.
SAFETY: Agencies
should develop procedures specific to their needs.
REFERENCES:
Agencies should refer to agency-specific documentation and manufacturers'
manuals.
General
Guidelines for a Surveillance Photography SOP
TITLE: Surveillance
Photography SOP
PURPOSE: To
document acts and individuals engaged in those acts as they occur
NOTE: Surveillance
activities may involve highly specialized techniques and equipment
that require technical training and knowledge and are best accomplished
by trained specialists.
EQUIPMENT: (Image
Capture Devices)
- Silver-based
media film camera. The minimum recommendation is a 35 mm camera
with capability to disable both the flash and infrared auto-focus
transmitter
- Digital still
imaging. The minimum recommendation is for a camera with a minimum
pixel resolution of 2000 x 1500 pixels (3 megapixels), capability
to accommodate long telephoto lenses, and disable the flash and
infrared auto-focus transmitter. In covert surveillance situations,
illumination of the photographer by the LCD screen may compromise
safety
- Video imaging
can be used in a supplementary capacity. S-VHS, Hi-8, or better-quality
formats are recommended. It is suggested that cameras have the
ability to incorporate external/wireless audio, disable on-camera
audio, and incorporate/disable in-camera image stabilization (See
Video Cameras)
- Other standard
photographic equipment as necessary
NOTE: State
laws may limit the legality of audio taping. Check local statutes
for legality of all surveillance activities.
SPECIALIZED
EQUIPMENT: Night vision or thermal imaging equipment
PROCEDURES:
Agencies should follow agency-specific step-by-step instructions
for documenting crime scenes. If audio is used, simultaneous recording
of audio with video on the same media and testing of the system
is strongly recommended.
CALIBRATION:
If necessary, agencies should develop procedures specific to their
needs.
CALCULATIONS:
If necessary, agencies should develop procedures specific to their
needs.
LIMITATIONS:
The successful capture of images sufficient for identification of
depicted individuals and/or objects (e.g., license plates) will
require close attention to the selection and appropriate use of
equipment. Images captured digitally or with video typically have
a limited enlargement capability that is less than those captured
using 35 mm film (See Advantages and Disadvantages
of Major Image Capture Technologies in Field Applications).
The successful capture of images also requires utilization of fresh
media (e.g., film that is not past expiration and has been stored
properly or new, unused videotapes) and well-maintained equipment.
SAFETY: Agencies
should develop procedures specific to their needs.
REFERENCES:
Agencies should refer to agency-specific documentation and manufacturers'
manuals.
General
Guidelines for a Tactical Survey SOP
TITLE: Tactical
Survey SOP
PURPOSE: To
document conditions at a location so that plans can be made for
future law enforcement activities
NOTE: This type
of photography is directed at obtaining general information regarding
the physical layout and major contents of a location in preparation
for law enforcement activities.
EQUIPMENT: (Image
Capture Devices)
- Silver-based
media film camera. Minimum recommendation is 35 mm camera
- Digital still
imaging. Minimum recommendation is for a camera with more than
1600 x 1200 pixels (>2 megapixels)
- Video imaging
can be used in a supplementary capacity. S-VHS, Hi-8, or better-quality
formats are recommended. It is suggested that cameras have the
ability to incorporate external/wireless audio, disable on-camera
audio, and incorporate/disable in-camera image stabilization (See
Video Cameras)
- Other standard
photographic equipment as necessary
PROCEDURES:
Agencies should follow agency-specific step-by-step instructions
for documenting crime scene locations.
CALIBRATION:
If necessary, agencies should develop procedures specific to their
needs.
CALCULATIONS:
If necessary, agencies should develop procedures specific to their
needs.
LIMITATIONS:
Location-specific limitations may apply.
SAFETY: Agencies
should develop procedures specific to their needs.
REFERENCES:
Agencies should refer to agency-specific documentation and manufacturers'
manuals.
General
Guidelines for a HAZMAT Scene Photography SOP
TITLE: HAZMAT
Scene Photography SOP
PURPOSE: To
permanently document, by qualified personnel, evidence and other
details at a crime scene that may contain biological, chemical,
and/or radiological hazards
NOTE: A careful
assessment of each HAZMAT scene is necessary prior to committing
any personnel or equipment. The means for inserting, removing, and
sanitizing equipment and personnel from a scene should be planned
prior to initial entry. HAZMAT scene photography generally requires:
- Recording
information that the crime scene personnel may not realize was
important at the time the images were captured
- Contending
with varying lighting conditions
- Accurately
representing all of the details and colors in a scene
- Getting close-up
and wide-angle images with accurate spatial relationships
HAZMAT crime
scene photography is usually a time-limited activity when there
is only one opportunity to correctly complete the task. This type
of photography usually involves the use of protective clothing and
gear that will make the operation of photographic equipment more
difficult.
EQUIPMENT: (Image
Capture Devices)
- Silver-based
film cameras are recommended for use as the primary image capture
device. Minimum recommendation is 35 mm (SLR) camera capable of
manual override, interchangeable lenses, off-camera flash, and
tripod mount. If protective housings are not available but needed,
disposable, waterproof 35 mm cameras may be necessary for some
HAZMAT scene photography
- Digital still
imaging can be used as the primary means when the performance
of the equipment can be shown to meet anticipated needs or when
contamination issues may preclude the use of silver-based media.
Otherwise, digital still imaging can be used in a supplementary
capacity (See Digital Cameras). Minimum
recommendation is for a 3-megapixel camera
- Video imaging
can be used in a supplementary capacity. S-VHS, Hi-8, or better-quality
formats are recommended. It is suggested that cameras have the
ability to incorporate external/wireless audio, disable on-camera
audio, and incorporate/disable in-camera image stabilization (See
Video Cameras)
- Other standard
photographic equipment as necessary
SPECIALIZED
EQUIPMENT: Equipment for protecting personnel and camera systems
PROCEDURES:
Agencies should follow agency-specific step-by-step instructions
for documenting crime scene evidence.
CALIBRATION:
If necessary, agencies should develop procedures specific to their
needs.
CALCULATIONS:
If necessary, agencies should develop procedures specific to their
needs.
LIMITATIONS:
Protective equipment will hamper the use of some equipment, and
conditions may not permit the use of other equipment (e.g., flash,
film). (See Advantages and Disadvantages of
Major Image Capture Technologies in Field Applications)
SAFETY: Agencies
should develop procedures specific to their needs.
REFERENCES:
Agencies should refer to agency-specific documentation and manufacturers'
manuals.
General
Guidelines for an Aerial Photography SOP
TITLE: Aerial
Photography SOP
PURPOSE: To
document locations, activities, and geographical relationships using
aircraft as a platform
NOTE: Aerial
photography may involve highly specialized techniques and equipment
which require technical training and knowledge and is best accomplished
by trained specialists.
EQUIPMENT: (Image
Capture Devices)
- Silver-based
media film camera. The minimum recommendation is 35 mm camera
capable of manual operation
- Digital still
imaging. The minimum recommendation is for a camera with a pixel
resolution of 3000 x 2000 pixels (6 megapixels) or higher
- Video imaging
can be used in a supplementary capacity. S-VHS, Hi-8, or better
quality formats are recommended. It is suggested that cameras
have the ability to incorporate and/or disable external/wireless
audio and on-camera audio. It is strongly recommended that image
stabilization be used (See Video Cameras)
- Other standard
photographic equipment as necessary
SPECIALIZED
EQUIPMENT: Night vision or thermal imaging equipment
PROCEDURES:
Agencies should follow agency-specific step-by-step instructions
for aerial photography activities.
CALIBRATION:
If necessary, agencies should develop procedures specific to their
needs.
CALCULATIONS:
If necessary, agencies should develop procedures specific to their
needs.
LIMITATIONS:
Check the legality of all surveillance activities. Images captured
digitally or with video typically have a limited enlargement capability
that is less than those captured using 35 mm film (See Advantages
and Disadvantages of Major Image Capture Technologies in Field Applications).
Successful capture of images also requires using fresh media (e.g.,
film that is not past expiration and has been stored properly, and
new, unused videotapes) and well-maintained equipment.
SAFETY: Agencies
should develop procedures specific to their needs.
REFERENCES:
Agencies should refer to agency-specific documentation, manufacturers'
manuals, and local statutes.
General
Guidelines for an Accident Scene Photography SOP
General Guidelines
Covered Under General
Guidelines for Crime Scene Photography SOP
- General Guidelines
for an Arson Scene Photography SOP
- General Guidelines
for Autopsy Photography SOP
- General Guidelines
for a Bombing Scene Photography SOP
- General Guidelines
for a Mass Disaster Scene Photography SOP
- General Guidelines
for a Search Warrant Photography SOP
General
Guidelines Covered Under General
Guidelines for a First Responder SOP
- General Guidelines
for a Gang Related Graffiti Photography SOP
- General Guidelines
for a Field Mug Shots and Tattoos Photography SOP
- General Guidelines
for a Victim Photography SOP
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