Virtual Reality Photogrammetry (HD)

Posted by | Posted in , | Posted on 9.12.08


The American Society for Photogrammetry and Remote Sensing (ASPRS) defines photogrammetry as "the art, science, and technology of obtaining reliable information about physical objects and the environment through the processes of recording, measuring and interpreting photographic images and patterns of electromagnetic radiant energy and other phenomena." In this context, "art" refers to an advanced level of skill that can only be achieved through significant practical experience.
Photogrammetrists are skilled at using photographs to obtain reliable measurements. As used in forensic science , photogrammetry involves applying scientific and mathematical techniques to two-dimensional images in order to accurately measure two- or three-dimensional objects or to create three-dimensional models or reconstructions from the twodimensional images. Photogrammetry is sometimes referred to as remote sensing, because it is used to measure objects without coming into physical contact with them.
Although photogrammetry can encompass far range and aerial image creation, it is most often used in crime scene documentation at close range for either object identification or measurement. At crime scenes, it can be used to derive the locations of the perpetrator and victim during the event. It can be scientifically applied, long after the crime, to photographs and other images taken on-scene by forensic investigators in order to extract additional detail such as blood spatter , wound patterns, bite marks, and other minute evidence from photographs and other images. The extracted information can be used to develop evidence measurements or to create detailed crime scene maps.
During fire and explosion investigations , there may be minimal physical evidence and poor visibility, but much photographic (or other image) evidence gathered. Photogrammetric digital image processing techniques can produce enhanced images that may be readily viewed and interpreted, often providing important forensic information.
Photogrammetric techniques can be used to make corrections in oddly angled images in order to place objects in the correct planes and at the proper angles for crime scene reconstruction , as well as to make virtually unlimited three-dimensional measurements from available crime-scene photographs. This can be done at any time, which is useful for providing answers to new questions, or for allowing more detailed analysis of existing data.

Forensic photogrammetrists utilize specialized cameras and/or other imaging equipment, targets, measurement devices, and computer modeling software for the purposes of crime scene measurement and reconstruction. By so doing, they make it possible to create scaled images, diagrams or three-dimensional models in which there is accurate placement of evidence without necessitating physical contact with any aspect of the original scene.

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