Post Number: 58
|Posted on Sunday, March 26, 2017 - 02:15 pm: ||
Hi Tatyana -
The key words in your question about fingerprints seem to be "forensic photography."
Forensic scientists and crime scene technicians capturing digital images at crime scenes will generally have equipment capable of capturing RAW images. Law enforcement officers who are not scientists or CSIs often must use whatever camera equipment is available, and that can mean the use of smart phones capturing JPG images. Existing forensic standards allow such non-RAW image capture. For example, paragraph 4.6 in the existing national fingerprint standard for digital imaging at www.nist.gov includes the following:
Capture in a raw file format is recommended, but may not be possible in some cases, depending on the equipment.It is a myth that "RAW is a digital negative of a photograph and cannot be altered." Any digital images can be altered, which is why recording the hash values of all digital images (RAW, JPG, BMP, PNG, etc.) is the first process listed in the SWGIT document "Best Practices for Maintaining the Integrity of Digital Images and Digital Video" at www.swgit.org.
There is not a 6 mega pixel camera requirement for capturing latent print images. As cited in the above link the recommendation (not a requirement) for capturing latent print images is 1000 ppi spatial resolution when possible. For scanning or photographing inked (record) finger or palm prints, the standard is 500 or 1000 ppi. When latent print images from crime scenes are captured at less than 1000 ppi, the scale in the image is typically used to resample the image to 1000 ppi for common forensic processes such as automated fingerprint identification system (AFIS) searching.
When no scale is captured in the image, the spatial resolution can be estimated well enough to enable AFIS searching (and subsequent identifications) by measuring the number of pixels from the middle of one ridge to the middle of the next (usually by measuring across five adjacent ridges to get an average). At 1000 ppi, the average number of pixels for adult finger or palm prints is usually in the neighborhood of (about) 22 from the middle of one ridge to the middle of the next ridge (but seldom exactly 22).
Jesse J (Unregistered Guest)
Posted From: d108-181-42-187.abhsia.telus.net
|Posted on Tuesday, January 10, 2017 - 10:48 pm: ||
To answer your question at face value- yes smart phones are able to photograph fingerprints quite well. However, photographs of evidence are required to be taken in RAW format and have a resolution of at least 6 mega pixels. RAW is a digital negative of a photograph and cannot be altered, which is very important for court cases and showing the integrity of the digital image. I'm not aware of smart phones that can capture in RAW, and I'm not too sure of their resolutions.
Tatyana Gancheva (Tgancheva)
Post Number: 1
|Posted on Monday, January 09, 2017 - 09:28 am: ||
As a topic of my Project I would like to know if the modern smartphone's are able to capture FP for Forensic Photography from a crime scene (or lifted FP) and be used for identification of criminals? Is there any recent/similar studies known? What is the "up-to date" tendency of using Smartphones?
Any information would be Much appreciated.
Thank you very much