anna ponas (Annaponas)
Post Number: 2
|Posted on Saturday, January 05, 2013 - 02:30 pm: ||
so as far as i understand, there are known techniques that can compensate for the change due to growth. but they must be used manually.
if i were the manufacturer i would just use the age of the person at the time of fingerprinting to calculate that person's age today to scale the print accordingly. i would use the national average height at that age or something.
i read here that kids get fingerprinted often in practice. so it seems that the manufactueres are lazy/cheap for not providing this simple feature.
R. Fairchild (Unregistered Guest)
Posted From: ip72-219-232-121.dc.dc.cox.net
|Posted on Saturday, January 05, 2013 - 11:22 am: ||
All AFIS systems allow for growth/enlargement of hands and fingers to some extent, thus their accuracy in identifying a person fingerprinted for auto theft at age 18 when they weighed 130 pounds and a decade later when they are three inches taller and weigh 100 pounds more.
However, AFIS systems are not normally configured with algorithms to compensate for the extreme variance in relative friction ridge image spatial resolution between small children and fingers from the same person decades later when they are an adult.
In most AFIS operations, this absence of technology to deal with children's fingerprints when they are adults is not a problem because federal/state/provincial and local civil/criminal/privacy laws and regulations preclude input of children's fingerprints in AFIS databases. Those systems (typically civil) which do record children's fingerprints tend to also record iris and face biometric modalities to increase potential for successful identification of the person after they have grown from a child into an adult.
In some circumstances (kidnapping or missing child) a child's fingerprints may need to be searched (with or without retention/registration) in an AFIS decades later (when the child would be an adult). In such circumstances the child's fingerprints are typically enlarged to a uniform degree so the width between ridges is an average distance relative to adult fingerprints. For example, one method is to digitally enlarge the central area of an index or middle finger of the infant/child and count across the white space furrows between at least six ridges, then adjust the digital image overall size so the average pixels from the middle of each ridge to the adjacent ridge is 11 pixels at 500 pixels per inch (or an average of 22 pixels in 1,000 pixels per inch systems). This can sometimes be successful even when the only infant fingerprints available are fingerpaint impressions, but the success (of course) depends on the quantity and quality (clarity) of friction ridge detail recorded in the impression.
Identification of children from fingerprints is only one method, and human DNA must be also be considered for missing children.
anna ponas (Annaponas)
Post Number: 1
|Posted on Friday, January 04, 2013 - 06:44 pm: ||
Kids grow in height and width. Do current electronic fingerprint matching systems compensate for the growth in height and width of kids. say from 10 year to 20 years. I imagine that skin and fingerprints get stretched in a non uniform, non linear, way. Thanks in advance for your thoughts.