What We Do
Knox & Associates uses the latest in photogrammety software to obtain measurements from photographs. Our photogrammetry software allows us to obtain two-dimensional measurements from a single photograph that was taken with an unknown camera. We can also obtain three-dimensional measurements from two photographs that were taken with an unknown camera.
Our photogrammetry software also allows our experts to use a calibrated camera to photograph a scene or vehicle and obtain measurements from the photographs. This techniques can be used to save time in the field or to obtain measurments of a scene that cannot be accessed by land.
This scene mapping was obtained using laser mapping equipment and photogrammetry.
Knox & Associates can take aerial photographs of a scene and use those photographs to create a three-dimensional computer model of the scene.
Knox & Associates uses Photomodeler, a sophisticated software package that allows our experts to obtain measurements and build three-dimensional computer models from photographs.
The scene mapping is used to prepare a scale diagram to be used in reconstructing the shooting incident.
Vehicle Damage Measurements
Knox & Associates can use two photographs of a damaged vehicle taken with an unknown camera to obtain measurements of the damage to a vehicle. This allows us to perform accident reconstruction even in cases where the evidence is long gone.
This is a three-dimensional model that was made from photographs of a damaged vehicle. It was used to analyze the crush damage done to an accident vehicle several years prior. The vehicle was no longer available, but photographs taken a short time after the crash were used to create this model.
Suspect Height Measurements
Knox & Associates can use photogrammetry to determine the height of suspects in surveillance video footage. In many cases, the perspective and lens distortions introduced by low-quality surveillance video systems can significantly affect size and spatial appearance of objects and people captured by surveillance video systems. The height of a suspect cannot be determined visually from a perspective image; it must be determined using photogrammetry.
The height of this suspect was determined by using measurements of the doors to scale and orient the photograph and then tracing the suspect's outline in the plane of the doorway. This evidence was used by prosecutors to discredit a defendant's claim that the suspect in the video was too short to be him.
The suspect's outline has been mapped over the scale diagram of the doors for use in CAD software.
A three-dimensional model was created to demonstrate to the jury how the camera's position affects perspective. In this view, the camera perspective has been removed, and the suspect's silhouette is shown from the perspective of a person standing in the store.