Trends in Forensics

Automatic 2D and 3D object scanners have already been used for many years to solve firearm crimes, saving valuable time by automating the process of evaluating fired ammunition parts. The scan data are compared with results from extensive databases – for example, it is possible to identify the weapon to which a projectile found at a crime scene belongs. Forensic experts heavily rely on international databases and the opportunity to compare large amounts of data in the fight against organized crime and arms trafficking.

However great the advantages of new forensic technologies may be, the comparison microscope and human judgment are still at the end of the evidence chain. Trace evidence is so multi-faceted and complex that only a human is capable of assessing and understanding it.

All forensic investigations depend on obtaining 100 % watertight evidence. Many courts demand that the party presenting the evidence views and compares the objects in one image. So the comparison microscope or macroscope remains the main tool, and its efficiency is enhanced by smart accessories and innovative software. The “Automontage“ software module from Leica Microsystems, for example, produces high-quality multifocus images at high recording speeds. The 3D viewer automatically creates a 3D surface model that can be displayed or illuminated from any angle to allow a close-up look at details.

A current trend in forensics is the accreditation of the analysis equipment. It is important to only use calibrated or certified instruments to ensure that the evidence can be admitted. The forensic lab must be able to prove that the equipment’s specifications fall within the tolerances specified by the nationally valid accreditation labs. By 2016, all forensics labs in Germany are to be certified to ISO and CE standards.

The manufacturer of the microscope also has to give it a final check before it leaves the factory and add a measurement or acceptance protocol specifying, for example, the measurement accuracy and measurement uncertainty for each objective. Comparison microscopes and macroscopes from Leica Microsystems already comply with ISO/EC 17025:2005 and can be calibrated by specially trained engineers to these standards upon customers request. Fixed focal length objectives like the PL APO MACRO series of the Leica FS C and FS M offer a clear advantage over zoom objectives. With Leica objectives, the maximum deviation of the total magnification between the left- and right-hand imaging channel is less than 0.1%. Zoom objectives with clickstop functions may have deviations of as much as +/- 5%. The telecentricity of Leica objectives are another factor contributing to measuring accuracy. For more on telecentricity, go to Science Lab.

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