Forensics: Half-Day Workshop: Sept. 17 (past)

A free workshop for forensics professionals was held on September 17, 2013 in the CHI studio in San Francisco. More...

RTI Training for Forensics (past)

On December 3–7, 2012, Cultural Heritage Imaging (CHI), in collaboration with Imaging Forensics, held a specialized 40-hour training class on Reflectance Transformation Imaging (RTI) for forensic professionals at the Sheriff's Office in San Luis Obispo, California. The training featured hands-on instruction on the forensic applications of RTI.

Forensics professionals can learn the RTI technique in any training course offered at CHI. Below are some evaluation comments from trainees in the December 2012 class.

“Excellent! Both instructors were informative, patient, and knowledgeable. The pace was perfect. Great job!”

“Unbelievable! Very impressed with the organization and presentation of materials.”

“Tremendous! Loved it and can’t wait to use this new technique and technology.”

“Very interesting method that can be used in any field of forensic science.”

forensic footprint study

RTI of a footprint in dirt (see enlarged image with details below)


RTI result of a fingerprint in wax

RTI result of a fingerprint in wax. Right side shows normal lighting,
left side shows mathematical enhancement that brings out surface details.

Reflectance Transformation Imaging (RTI), when applied to forensics, can dramatically improve the visualization of textural evidence, including footwear, tire impressions, toolmarks, latent fingerprints, obliterated serial numbers, and questioned documents features such as indented writing and ink crossovers.

Forensics RTI Examples

The video below demonstrates how handwriting and indentation analysis can be enhanced through Reflectance Transformation Imaging (RTI). Interactive relighting and mathematical enhancements are used to show details of the writing surface.

Indentation Analysis via Reflectance Transformation Imaging (RTI) from Cultural Heritage Imaging.

tool marks array enhanced by RTI

RTI results of tool marks on a metal plate. The left panel shows sample tools used to make the marks; the right panel is a composite image with the left part shown in the “default” lighting mode, and the right part showing the surface under “specular enhancement” with no color, which emphasizes fine details of the surface shape.

footprint enhanced by RTI

RTI of a footprint in dirt. The left side of the divided image shows the “default” viewing mode. On the right side, the surface details are enhanced using “diffuse gain”. The enlarged callout panel reveals in even greater detail the way RTI has enhanced the image.