By Roland Piquepaille
In "Courtrooms could host virtual crime scenes," New Scientist writes about a software called Instant Scene Modeler (iSM), which can build an interactive 3D model from a few hundred frames of a scene shot by a dual-head camera developed by MD Robotics. Users, who can be lawyers, judges, jurors or detectives, can zoom on any object in the 3D model. Other usages of this gun-shaped camera and its associated software include remote explorations of mines, or even other planets such as Mars. The software works by identifying common features in the sequence of images taken by the special camera. And it has already been used to pilot Aibo, Sony's robotic dog. Read more...Here are the opening paragraphs of the New Scientist article.
Lawyers, judges and jurors could soon explore crime scenes in three dimensions in the courtroom, in the same way that video gamers explore virtual worlds.
Software called instant Scene Modeler (iSM) re-creates an interactive 3D model from a few hundred frames of a scene captured by a special video camera. Users can zoom in on any object in the 3D model, measure distances between objects and look at scenes from different angles.
Currently investigators try to recreate the scene of the crime in court by sifting through photos or sketches, but this approach is limited and time-consuming, explains Piotr Jasiobedzki, iSM's project manager at MDRobotics in Toronto, Canada. The software could also assist detectives during their investigations.
Here is how this works.
The system uses a gun-shaped stereo-camera that consists of two ordinary video cameras aligned at a set distance from each other. This enables the depth of the captured scene to be calculated at every point, just as a pair of eyes gauges distances. (Image credit: MD Robotics, iSM_InfoSheet (PDF format, 1 page, 1.25 MB)
And here are links to two animations from MD Robotics showing a crime scene sequence (4.2 MB) and a crime scene 3D model (4.3 MB).
The amazing thing about this software is that it automatically creates calibrated 3D models -- and believe me, this is tricky.
iSM is different because it creates a virtual model of the scene that can then be explored from any angle. It does this by using a set of algorithms called SIFT (Scale Invariant Feature Transform) developed by David Lowe, computer vision expert at the University of British Columbia in Vancouver, Canada
SIFT very quickly identifies common features in sequential images, Lowe told New Scientist, allowing separate 3D images to be transformed into a virtual 3D world. The virtual world is rendered by a graphics gaming card inside an ordinary laptop or PC.
For more information about David Lowe's work, you can read one of his latest papers, published by the International Journal of Computer Vision, "Distinctive Image Features from Scale-Invariant Keypoints" (Volume 60, Number 2, November 2004, Pages 91-110). Here is a link to the abstract and here is the beginning of it.
This paper presents a method for extracting distinctive invariant features from images, which can be used to perform reliable matching between different images of an object or scene. The features are invariant to image scale and rotation, and are shown to provide robust matching across a a substantial range of affine distortion, addition of noise, change in 3D viewpoint, and change in illumination. The features are highly distinctive, in the sense that a single feature can be correctly matched with high probability against a large database of features from many images.
Finally, if you're a specialist in this field, here is a link to the full paper (PDF format, 28 pages, 501 KB).
Sources: Celeste Biever, NewScientist.com, March 10, 2005; and various websites
Related stories can be found in the following categories.
Famous quotes containing the words watching, crime and/or scenes:
“Should we have stayed at home and thought of here?
Where should we be today?
Is it right to be watching strangers in a play
in this strangest of theatres?”
—Elizabeth Bishop (1911–1979)
“Although good early childhood programs can benefit all children, they are not a quick fix for all of society’s ills—from crime in the streets to adolescent pregnancy, from school failure to unemployment. We must emphasize that good quality early childhood programs can help change the social and educational outcomes for many children, but they are not a panacea; they cannot ameliorate the effects of all harmful social and psychological environments.”
—Barbara Bowman (20th century)
“O scenes of the beautiful world! Never have you presented yourself to more appreciative eyes.”
—Thomas Mann (1875–1955)