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Can Measurements be Made from Law Enforcement Body-Worn Camera Video?

Posted on Wednesday, December 20th, 2017

This is a guest blog post written by collision instructor, and active LE officer, Bobby J. Mullinax. See bio below. Why Use Body-Worn Camera Video for Measurements? Photogrammetry is a technique that uses images and photos to obtain accurate 2D and 3D measurements and diagrams of the real world. A body-worn camera stores a video that could possibly be used as a data source in photogrammetry for crime or accident scene forensics. You may not need to use body-worn cameras as the photograph source for your photogrammetry project, but you may find yourself in a situation where you have to. How many times has a crash or crime scene investigator been tasked with putting together a complex puzzle, only to find…Read More


Using Photogrammetry in Court

Posted on Wednesday, November 29th, 2017

Court Room Gavel

This is a guest article by forensics consultant, and trainer, Dan Mills. Bio below. Anyone in a technical field that brings evidence to court must consider both the evidence they are presenting, as well as the admissibility of their methods. First, a definition of Admissible Evidence: Evidence that is formally presented before the trier of fact (i.e., the judge or jury) to consider in deciding a case. The trial court judge determines whether or not the evidence may be proffered. To be admissible in court, the evidence must be relevant (i.e., material and having probative value) and not outweighed by countervailing considerations (e.g., the evidence is unfairly prejudicial, confusing, a waste of time, privileged, or based on hearsay). Also termed competent…Read More


Forensic Photogrammetry: A Case Study

Posted on Monday, October 16th, 2017

Forensic Playground photo repaired

This is a guest article by forensic imaging consultant Mike Mayda. Bio below. Why Use Photogrammetry in Forensics? Photogrammetry can be a very powerful tool in forensic analysis. It is often useful to have an accurate 3D reconstruction of an accident or crime scene, especially in cases where position, distance and perspective are important. Given the large number of photos taken at these scenes, photogrammetry can be a practical way for investigators, lawyers, and insurance adjusters to obtain better information. In addition, photogrammetry can be used to preserve or recover measurement data long after the on-scene investigation has concluded. This is valuable as it can often be months before an investigator re-examines a scene and discovers a new piece of…Read More


PhotoModeler in Accident Reconstruction and Trade Show

Posted on Monday, September 11th, 2017

PhotoModeler has been the premier photogrammetry tool for accident reconstruction and incident scene forensics for more than 20 years. Continuing with that tradition we announce two items: Upcoming AR Conference Booth Drones / UAV in Accident Reconstruction Page   Accident Reconstruction Conference PhotoModeler will have a booth at the 2017 ARC-CSI Crash Conference, September 18-21, 2017, at the South Point Hotel, Las Vegas, NV.  If you are attending the show please come by for a chat! We will be demonstrating the newest in drone / UAV use with PhotoModeler as well.   Using Drones in Accident Reconstruction PhotoModeler has been used since the early 1990s as a key tool in the accident reconstructionist’s toolbox. For the most part, until recently, this…Read More


With A Camera and a Laser Reconstruct a Crime Scene

Posted on Monday, June 19th, 2017

Unfortunately, this is an all too common story: The convenience store clerk was alone when a man entered the store. He demanded money and cigarettes. When the clerk refused, the clerk was beaten and then shot, leaving no eyewitnesses to this horrific crime. But there was a ‘witness’ – the store had a single security camera. The suspect’s face was not clear in the video, but he was imaged walking behind the cash desk and around the store. What next? The forensic specialist needed to extract some key measurements from the security video, such as the suspect’s height, some measurements on his clothing, and where he stood in the store at various times during the incident. How can these measurement…Read More


With a Camera Determine Who Caused a Collision

Posted on Wednesday, March 22nd, 2017

A New Blog Series We introduce a new blog series called “With A Camera“. With each blog post in this new series we describe an application of close range photogrammetry – that is, 3D measurement and modeling with a camera. The articles will describe significant real-world problems and how photogrammetry was able to uniquely solve them. Future topics might include engineering, surveying, architecture, construction, drones, mining, agriculture, forensics, scientific and industrial measurement, and archaeology. In each post, we will summarize the problem, how it was solved, and as well point out resources on the web for further study. The first post of this new ‘With A Camera’ series is the interesting one of measuring accident and collision scenes. Collisions and…Read More


Tip 85: Measuring suspect height using a single photo from an unknown camera

Posted on Tuesday, September 1st, 2015

Surveillance cameras are ubiquitous in public places. Crimes and/or the suspects participating in them are often captured on one or more of these cameras. Measuring the height of a suspect in a scene is usually a key piece of evidence in identifying the individual. PhotoModeler can be used to accurately measure the height of a suspect in a single image from an unknown camera. The example shown in this tip is a simulation of a crime scene where the suspect’s height needs to be measured. Since the source of the image is unknown, PhotoModeler needs to ‘solve’ the camera’s parameters (e.g. focal length), using some known information about the scene. In PhotoModeler, this is called the “Inverse Camera” feature. The investigator…Read More


Using a Dropcam for Forensics and 3D Measurement

Posted on Tuesday, May 19th, 2015

The Dropcam security camera is one of several easy-to-use IP cameras on the market for self-monitoring security systems. This article describes a forensic simulation using Dropcam imagery, and the 3D-from-photos software, PhotoModeler. PhotoModeler is the most comprehensive solution, at any price, for working with images from a variety of sources to produce accurate 3D measurements and models in many different fields. In this example, the height of a burglary suspect is measured in a crime scene simulation, and the location of a step ladder is measured in a workplace accident scene simulation. These are carried out in a retail shop with the shop owner’s own Dropcams. These types of forensic measurement tasks can be carried out a number of ways in PhotoModeler; this…Read More


Tip 62: Forensic Modeling of Trajectories with Photogrammetry

Posted on Friday, May 30th, 2014

A common forensic task is to determine the position of a shooter in a crime scene. One technique uses bullet trajectory rods and calculations of intersection and extension. Photogrammetry, the science of performing measurements from photos, can be used to model the cylindrical trajectory rods, using a normal DSLR camera, and find their position and angles in 3D space. PhotoModeler has such a cylinder modeling tool as well as the ability to extend these rods virtually to help determine shooter position. In the case shown in this video, the trajectory rods have been inserted into bullet holes in the side of a vehicle. A number of photographs from different angles are taken. A standard PhotoModeler project is set up, and…Read More


Photogrammetry helps police clear accident scenes quickly and safely

Posted on Wednesday, August 21st, 2013

Car accidents are an ordeal for everyone. They’re traumatic for the people involved, of course, but they also affect everyone else on the road. The more serious the incident, the more likely that multiple lanes will be blocked, and the longer it will take to get it cleared. The police officers at the scene have one of the most difficult jobs of all. They have to measure and map the scene and the vehicles in scrupulous detail so that the courts can get a clear picture of exactly what happened. To add to their challenge, they have to do all of this in the middle of a busy, backed up roadway. The Solution is Photogrammetry Fortunately, there’s an easier way…Read More


 


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