Soon, crime scene measurements using a single photograph

Washington, Dec 2 (ANI): Scientists from University of Salamanca have developed a novel technique that would help forensic police to extract metric data from crime scenes using just a single photograph.

According to Diego Gonzalez-Aguilera and his colleague Javier Gomez-Lahoz the new procedure offers "a novel approach for documenting, analysing and visualizing crime scenes".

The proposal might make it possible to reconstruct a crime scene in 3D.

"We have studied an unprecedented and original line of research in the field of criminology and forensic engineering, which makes it possible to derive metric data from a single image", Gonzalez-Aguilera, co-author of the study and a researcher in the Department of Cartography and Soil Engineering at the University of Salamanca (in the University's Avila offices), told SINC.

The process starts by capturing an image that must include easily-identifiable details and at least three vanishing points (the convergence point of straight lines projected in one direction) as well as at least one distance in the scene.

These data are used to extract the structural components or most important objects in the image "automatically and robustly".

The researchers also calibrate the camera to be able to determine both the internal (focal distance, main point and radial distortion) and external (lens turns and lens viewpoints) parameters.

As the structural features are geometrically related to the features of the scene and the camera itself, it is possible to take measurements and to analyse the dimensions of the scene based on distances, angles and surfaces.

This means that, at any time after having taken a photograph of a crime scene, forensic police could establish that a knife was 32cm away from the victim, or that there was an angle of 37 degrees between a trace of blood, a footstep and a bullet hole.

This technique has been developed within the field of photogrammetry, a procedure used to determine the geometrical properties of an object based on photographic images.

"Until now, this discipline required at least two images to be used in order to reconstruct a crime scene, but now we have broken that barrier," said Gonzalez-Aguilera.

The study is published in the Journal of Forensic Sciences. (ANI)