Hi,
Would it be correct to describe the substrate of an impression taken via Livescan as being glass (the Livescan platten)? Could it also be said that the impression doesn't have a matrix, as it is an image of the FRD itself? Also, would the development medium simply be light? Or is there some touch-sensitive element to the glass that contributes to this (I appreciate there are many different types of Livescan sysytems).
Dan Perkins
ACE-V & Livescan
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Boyd Baumgartner
- Posts: 567
- Joined: Sat Aug 06, 2005 11:03 am
Re: ACE-V & Livescan
I'd say for an optical sensor that sounds pretty accurate.
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Kasey Wertheim
- Posts: 161
- Joined: Sun Jul 10, 2005 6:55 am
Re: ACE-V & Livescan
Dan,
Generally, I have thought about substrate and matrix in terms of both latent prints and known prints, and development medium only in terms of latent prints. But you bring up an interesting point.
I think that the substrate is glass and matrix is still any substance on the friction ridge skin. I say this because many livescan station operators have a difficult subject clean and moisturize the skin prior to taking an impression. Your average subject may not need the additional matrix because existing constituents are suitable, but I think you still have to consider matrix this way for livescan.
The difference with defining this over inked prints is the light and electronic capture of it. These elements can introduce distortion artifacts as we have all seen - the slippage of the skin over time as the capture is being executed. This is very different than ink, as instead of simple smearing we can get breaks in ridges, mis-matched ridge alignment, etc. and all at very high contrast that doesn't look like smearing. Part of me likes your analogy to development medium, but I think that we could define this as an entirely different dimension than the traditional Ashbaugh approach of substrate, matrix, skin. This would apply to any capture of skin - ultrasound, multi-spectral contactless, x-ray, you name it. So perhaps simply 'capture' distortion in between Ashbaugh's 'layers' of matrix and skin?
-Kasey
Generally, I have thought about substrate and matrix in terms of both latent prints and known prints, and development medium only in terms of latent prints. But you bring up an interesting point.
I think that the substrate is glass and matrix is still any substance on the friction ridge skin. I say this because many livescan station operators have a difficult subject clean and moisturize the skin prior to taking an impression. Your average subject may not need the additional matrix because existing constituents are suitable, but I think you still have to consider matrix this way for livescan.
The difference with defining this over inked prints is the light and electronic capture of it. These elements can introduce distortion artifacts as we have all seen - the slippage of the skin over time as the capture is being executed. This is very different than ink, as instead of simple smearing we can get breaks in ridges, mis-matched ridge alignment, etc. and all at very high contrast that doesn't look like smearing. Part of me likes your analogy to development medium, but I think that we could define this as an entirely different dimension than the traditional Ashbaugh approach of substrate, matrix, skin. This would apply to any capture of skin - ultrasound, multi-spectral contactless, x-ray, you name it. So perhaps simply 'capture' distortion in between Ashbaugh's 'layers' of matrix and skin?
-Kasey
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Dan Perkins
- Posts: 46
- Joined: Fri Apr 18, 2008 5:39 am
- Location: London
Re: ACE-V & Livescan
Thanks for your thoughts Kasey, I like the idea of describing a new type of distortion - it may be of use in explaining 'spurious minutiae'.
Dan
Dan