Here is the text portion only of a recent article posted in Forensic Magazine.
Link to article
here.
Documenting Clothing in 3D
By Jon J. Nordby, Ph.D., D-ABMDI and Eugene Liscio, P.Eng.
When inspecting clothing from a homicide case, it is usually necessary to measure where injuries may have occurred on the body. There may be any number of irregular shapes, fluid stains, cuts, or markings that are highly irregular, curved, or scattered. Of course the clothing moves often independently of the body’s movement so there will be differences between data from the body and data from the clothing. It can be useful to document both similarities and differences.
Some markings may wrap around large portions of the body such that they are difficult to map and measure accurately, especially on the curved portions of the torso or on the legs. Therefore, it is often customary to take an article of clothing and place it flat on an inspection table for photos and measurements with a linear scale. The end result is a set of 2D coordinates that locates the position of any particular marking.
Although this method is the simplest and at times, perfectly acceptable, there are many other instances where placing the clothing on an accurately sized mannequin produces the most meaningful results. A typical example is in a shooting case where there may be multiple perforating/penetrating gunshot wounds to the body. The similarities (or dissimilarities) between trajectories of the clothing and those on a body can lead to significant clues about the position of the body at the time of the shooting (or some time thereafter). This data about the clothing can help show the body position when the shooting took place (i.e. turning, crouched...etc.) given the relative position of the clothing defects.
One means of recording the 3D positions of such clothing defects or marks on clothing involves using a 3D laser scanner. After putting the clothing on a typical mannequin, we use the laser to sweep through one side of the mannequin, creating a 3D mesh from the surface points. As more scans are done and pieced together, the final completed model is available for direct measurement and inspection by using any 3D Computer Aided Drawing (CAD) package.
An alternative method of recording point positions on clothing involves using close range digital photogrammetry. By using a digital camera and some specialized photogrammetry software, photos are taken in a "ring" fashion around a manikin to document all sides of the clothing. The photos are then uploaded to the software and processed to give 3D point positions.
The benefit of having such a 3D model of the clothing as it would naturally sit on the body is that the measurements become more accurate (closer to the true value). Bullet trajectories through clothing and either into or through bodies also become more accurate as well as easier to interpret and explain to a jury. In addition, bloodstains and other markings on the clothing such as rips, incisions, or abrasions, can be measured and reproduced in their true shape, not simply as a flat 2D view from the inspection table.
