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Weighted and Cone Style Photogrammetric Markers

Scene diagramming made easy using RPMs

Designed and sold by DeChant Consulting Services (DCS) Inc., Weighted and Cone Style Photogrammetric Markers (PM's) assist in measuring features points of interest during accident investigation. Noteworthy in their functionality, the PM's assist in fast and accurate camera orientation in iWitness to quickly image and measure a scene. PM's are used by law enforcement investigators and accident reconstruction practitioners across America. The combination of PM's affords very rapid and safe evidence mapping at the scene.

Below are sample illustrations of the DCS Weighted and Cone Style Markers. The white dots and alpha characters are double-sided and concentric.

Oblique view of DCS weighted style markers for iWitness photogrammetryCrash Scene Measured with DCS PM's and iWitness

On the left: The face and base of an alpha character PM with galvanized weight, which is affixed by special hook & loop Velcro. Center: The sand bag weighted single dot DM. On the Right: A crash scene were police investigators mapped the incident with a consumer grade digital camera, the PM's and iWitness. The PM's work well in conjunction with the iWitness target offset feature which enables the 3D point to be automatically projected in the Z-axis up/down direction (e.g., to the ground surface were they are placed.) The XYZ projected coordinate(s) can then be optionally exported to CAD in the industry standard DXF format. The Weighted Style PM's work excellent in combination with the Cone Style Markers.

DCS Cone Style Photogrammetric MarkerThe optional style "Cone Style Markers") are available here

Storage and Deployment
PM's are designed to stack in a small container for easy storage in the trunk of a car, or on board an accident investigation vehicle. There is ‘no fuss’ in access, deployment or storage of the PM's, which are also rugged to support long-term use and weather resistant. The galvanized weight affords stability in strong and gusting winds.

Specially designed for the iWitness photogrammetry system
The weighted style PM's are made from a 4mm thick closed-cell PVC, with the target dots and A-to-T letter identifiers being of a special Lexan decal material protected with a clear UV blocking agent, making them weather resistant and virtually scratchproof. An additional five "dot" PM's being 3mm thick and un-weighted are also provided in the set. The galvanized weights are supplied with a special hook and loop velcro, for the A-T style PM's.

Functionality and Options Available
Using a digital camera and the iWitness software system, the PM's are automatically and accurately marked in the images in 'one mouse click'. From terrestrial imaging, PM's can be used over distances of up to 200 feet (60m) in both daytime and night scene mapping applications. Using the advanced project stitching (3D transformation to control) feature available in iWitness, police have proven that PM's are highly advantageous on crash scene mapping projects covering 1000’ in overall length. The combination of PM's, a moderately priced consumer-grade camera and iWitness, the user is fully equipped and ready for low cost, rapid and accurate 3D photogrammetric scene mapping. A standard set consists of 20 Weighted PM's (letters A to T) and a quantity of five additional un-weighted dot PM's.


Please CLICK HERE for pricing and ordering information from the iWitness website.


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Contact Information
DCS Sales Department
DeChant Consulting Services-DCS Inc
PO Box 3261
Bellevue, WA 98009-3261
Phone: (425) 637-1865
Fax: (425) 454-2855
email at: sales@photomeasure.com