Demo Visualization Videos (Scans Do Not Appear at Full Resolution)The following videos highlight several aspects of the TopMatch-GS 3D scan acquisition and matching functionality. The first video shows scans of a number of 9mm Luger casings with granular, milled, and filed toolmarks. The video also demonstrates use of our unique virtual light source. The user can easily position the virtual light as they would a true light in the real world. When the user moves the virtual light features come in and out of view just as they would under an optical microscope. Why is a virtual light source necessary? When you look at an object on a monitor, even if it's a three-dimensional object, you are viewing a 2D rendering of the 3D object (unless you have fancy 3D glasses like at the movies).
The scans in the attached videos do not appear at full resolution. One has to view the scans on an ultra high-resolution display to fully appreciate the captured detail as the videos do not do the visualization justice!
To generate a 2D rendering, the computer takes the 3D object, a lighting model, and a viewing angle and computes a 2D view of what the object would look like from the specified viewing angle and with the specified light. Many 3D viewing programs allow the user to move the light; we provide the user complete control. When a user moves the light the 2D rendering is updated while the underlying 3D object remains unchanged. Therefore, the virtual light source assists the user in allowing visualization of features that may best be visible with a certain lighting position. Most importantly, our comparison algorithms do not consider the virtual light and instead directly compare the measured 3D topographies. That is, the algorithm does not compare 2D renderings, it directly compared 3D surfaces. Note the fidelity with which the aperture shear is captured. Moving the virtual light causes the striations to stand out. Finally, note that we currently only image the breech-face impression and aperture shear. We do not image the firing pin impression and so the firing pin impression may appear flat in the following video.
The second video highlights the heatmap visualization functionality of the matching software. Unlike other systems which provide little to no explanation on the detail of a match, the TopMatch system can display a heatmap to explain the computed match score. With a heatmap, the software color codes the surface of the casings to indicate the areas of geometric similarity (patent pending). This visualization provides interpretability and facilitates communication of your findings to those who are not experts in firearm forensics.
In both videos, images are not shown at full resolution.
Sample 3D visualization for yourself, download the free casing viewer here.