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also see Photographs
Any type of memory storage device used for capturing case photographs.
Deputies are responsible for the capture, archive, enhancement and documentation of digital photos taken in their assigned cases.
Image capture devices should be capable of rendering an accurate representation of the item of evidence. Different applications will dictate different standards of accuracy. The image should be captured at the highest possible resolution of your camera or a minimum of 1024 x 768 pixels. It is the responsibility of the Deputy to determine the resolution for an accurate representation of the item of evidence, but remember you can always lower the image resolution after the picture was taken. The same is not true for raising the quality.
The principal of image enhancement is to make an image clearer for analysis or interpretation.
No enhancement work shall be attempted on the original image.
Enhanced Images - Enhancement shall be conducted only on a copy of the original image. The Deputy creating an enhanced image is responsible for the verification of its accuracy and documentation of the methodology used to produce it. Documentation must be completed so the enhancement can be reproduced if necessary.
For additional resources see
PROCEDURES FOR COMPUTER SEIZURES.
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Only one case number of photographs will be accepted per media disk.
Take the first photo of the case number (Camera Shot Sheet)
Place memory card in a compact disc sleeve.
Do not place the
memory card into any
other type of packaging.
Place
the completed evidence tag on sleeve. Do Not Seal the
compact disc sleeve with the evidence tag.
Complete the property-evidence report. List the item description as "Digital case photo's." Indicate locker #63 (Headquarters) as the location of the memory card and sleeve. East Precinct may place the memory card and sleeve in any available locker.
Place the yellow and green copy of the property-evidence report in the property-evidence basket in the evidence processing room.
An Evidence Officer will transfer the digital images to a CD-R and return the formatted memory card to Patrol.
Magnetic fields delete or scramble data. DO NOT EXPOSE computer evidence to magnetic fields. Common magnetic media to consider include stereo speakers in the trunk of a vehicle, magnetic card keys, etc.
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PROCESSING YOUR OWN MEMORY CARDS
Only one case number of photographs will be accepted per CD-R.
If you are able to transfer your own digital images to CD-R then write the case number on the disk with a permanent marker and submit in a compact disc sleeve.
Place
the completed evidence tag on sleeve. Do Not Seal the
compact disc sleeve with the evidence tag.
Complete the property-evidence report. List the item description as "Digital case photo's." Indicate locker #63 (Headquarters) as the location of the CD-R and sleeve. East Precinct may place the CD-R and sleeve in any available locker.
Place the yellow and green copy of the property-evidence report in the property-evidence basket in the evidence processing room.
Ensure proper packaging; refer to the example board in the
evidence processing areas.
Place one barcode on the item and the corresponding barcode on the property receipt.
Place memory disc in appropriate card reader for transfer to CD-R.
Digital images are transferred to the primary digital imaging computers hard drive C or another hard drive specified for that purpose.
Each case will have a separate folder on the hard drive.
Additional digital images taken by different personnel under the same case number will require the creation of sub folders in the case file folder.
Images are written to a Write - Once Compact Disk Recordable media (CDR).
ARCHIVE CD-Rs are not to be used as a working copy under any circumstances.
Print out shot sheet with case number for case file (unless photograph are of a questionable nature or investigator indicates otherwise).
Format card and return to Patrol.
Place the item in a location best suited to the size of the
article, and area specified by the evidence room guide.
Using the barcode reader, scan the location of the shelf,
and then scan the barcode affixed to the item.
Place item in numerical order by case number.
DISPOSAL
Upon disposition of the case request authorization from the investigating officer.
Upon expiration of Statute of Limitations. Request authorization from the investigating officer.
Once disposal is authorized place all remaining compact disks into the shred basket.
Compact disks concerning death investigation photos will not be destroyed. Instead the CD will be placed in the case file with all original reports, and destroyed according to public record laws.
Image an imitation or representation of a person or thing, drawn, painted, photographed, etc. (per Websters Dictionary)
Archive Image Either the primary or original image stored on media suitable for long-term storage.
CCD (Charge Coupled Device) a grid of detectors that is capable of detecting a light and producing a pattern of electrical charges which are measured, converted to numbers and stored as a digital image. The quality of light collected by each sensor is measured by the metering system and recorded as a number. This number is then stored in the same grid position as the sensor that collected the sample. Each numeric value in the grid corresponds to a picture element (pixel) in each digital image.
Color Range The range of colors that can be detected by a sensor compared to normal human vision.
Copy Image A reproduction of the information contained in a primary or original image.
Digital Image An image that is stored in numerical form. The detail of the digital image is dependent upon both the resolution of the optical system used in the capture device and the density of the sensors on the CCD.
Duplicate Image An accurate and complete replica of an original image, irrespective of media.
Dynamic Range The difference between the brightest highlight and the darkest value that a sensor (film or CCD) can detect and record in a single image. Negative film provides 2-4 f-stops more dynamic range than most digital cameras.
Original Image An accurate and complete replica of the primary image, irrespective of media. For film and analog video, the primary image is the original image.
Primary Image Refers to the first instance in which an image is recorded onto is a separate, identifiable object or objects. Examples include: a digital image recorded directly to a hard drive, a digital image recorded on a flash card or digital image downloaded from the Internet.
Resolution amount of sharpness/detail in the image. Resolution is dependent of pixels in a digital image or the size of the grain in a silver-based film product. Generally speaking, the quality of the final image is determined by the amount of grain or the number of pixels contained in the primary image. See the following resolution technology definitions.
Input resolution The amount of information that a scanner can capture per inch of an original image. Limited by the physical resolution of the scanner
Scanning resolution The number of pixels per inch (ppi) that a scanner can acquire using its physical array of sensors.
Interpolated resolution The maximum amount of information that a scanner can simulate with the help of software.
Image resolution Refers to the total amount of digital information in an image expressed in pixels. Tells how many pixels are in any unit of measurement.
Output resolution The number of pixels per inch in a final image to be sent to a print. It is determined by the type of print and physical resolution of the device.
Printer resolution A measure of the actual dot pattern, both vertically and horizontally, generated by a specific printer. The greater the number, the smaller the dots created and the more continuous the tone appears.
Display resolution The number of pixels per horizontal inch of a monitor or the amount of digital information that a monitor can display at any given time. Determined by the quality of the computers graphic card.
Device resolution The physical limits of any input , output, or monitoring device. Often expressed in pixels or dot per inch.
DPI (dots per inch) A unit of measurement describing the resolution of an output device.
PPI (pixels per inch) The units which measure the resolution of a scan or scanned image.
LPI (lines per inch) A unit used to measure the row of dots in a halftone screen. Often referred to a screen frequency, it determines the way a final image looks when printed.
Working Image Any image subjected to processing.
Revised 03/10/04
