New footprint technology to help forensic experts solve crimes

An expert from University of Nottingham has developed a new technique that can extract additional information and create a digital picture of the personal footprint a culprint may have left behind when he stood or walked on a hard surface.

Based on a technique known as Frustrated Total Internal Reflection (FTIR) imaging, the discovery could lead to a "step change" in forensic footwear imaging.

"This technique uses ideas taken from 'A level' physics to form images of regions where shoes contact surfaces. The low cost and ease of implementation of the technique make it particularly appealing for forensic applications," said Dr James Sharp, an expert in physical properties of thin films of polymers and biopolymers.

"We are currently in the process of working with local police forensic laboratories and the Home Office to try to develop this work further," he added.

This new footwear analysis technique could also pave the way for other applications such as clinical studies of gait analysis or measuring how athletes interact with surfaces during high impact activities such as jumping, running or changing direction.

Much like fingerprints we all leave behind our own individual footprint.

Our gait determines weight distribution as we walk.

This, in turn, leads to specific wear and tear on the soles of our shoes.

Conventional FTIR maps the imprint of bare feet on a hard surface by shedding light through a transparent sheet of material as the foot hits the ground and reflecting it back at an angle.

Using the same technique, Dr Sharp's group has created more detailed images of the ridges on the sole of a shoe and how these contact a hard surface.

"The EMSOU-FS Footwear Unit is excited to be working in partnership with The University of Nottingham to develop an innovative solution to a very practical problem," added Charlotte Chester, footwear service delivery manager, EMSOU Forensic Services.

The research titled "Watch your step! A frustrated total internal reflection approach to forensic footwear imaging" was published in the open access journal Scientific Reports.