Researchers at the National Institute of Standards and Technology (NIST) in the US developed the 3D mapping system that combines a form of laser detection and ranging (LADAR), which is sensitive enough to detect weak reflected light, with the ranging accuracy made possible by frequency combs.
The frequency comb, a tool for precisely measuring different frequencies of light, is used to continuously calibrate the laser in the imaging system.
Operating with laser power of just 9 milliwatts - which is safe for the eyes at the instrument's infrared wavelength - NIST's 3D mapping system scans a target object point by point across a grid, measuring the distance to each point.
The system has wide dynamic range, enabling precise 3D mapping of targets with varied surface types and reflective properties.
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Researchers demonstrated the range by scanning footprints in soil, vegetation such as cactus (imaging individual spines), and complex mechanical devices such as a piston for a motorcycle.
As an example application, NIST's 3D mapping system could be used to make virtual casts of forensic evidence such as footprints in dirt.
Conventional plaster casts that record impression evidence normally require a lot of effort to make and are difficult to compare to each other or to shoes.
The tread may show individual wear marks from a bicycle pedal, for example, a type of detail that could link a specific shoe to a crime scene.