Tag Archives: Laurence R. Penn

“Fore! A Non-vehicular Drive Tracking Example”

Laurence R. Penn, Senior Forensic Animation / Video Specialist

Never one to turn down a challenge, when asked if I could track a ball just over 1.5 inches in diameter traveling at an average of 90 miles per hour in footage shot from a drone, I was more than happy to oblige. The footage I was working with was filmed from a DJS drone at the 2019 Legal Aid Golfing Outing in Plymouth Meeting, PA. Tracking rigid and organic objects in video footage can have varying degrees of difficulty. One of the first obstacles is the resolution and clarity of the video. Motion blur artifacts introduced by extremely high speeds, low lighting conditions or slow camera shutter speed can add an additional layer of complexity to the analysis. The distance of the subject from the camera also becomes an issue. Tracking a rigid body, such as a vehicle, with fixed features that stay at a relative distance from each other will also be a lot less intensive to track than an organic object such as a pedestrian, where posture and reference points are constantly changing.

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Fighting Fury with Forensics

Laurence R. Penn, Forensic Animation/Video Specialist

If you’re a regular streaming TV subscriber, you’ve probably heard of or even seen the documentary on Netflix, “Don’t F**K with Cats: Hunting an Internet Killer.” Likely, you don’t remember the events that took place in 2010; but, as the title undoubtedly suggests, what transpired and is expertly told in the original series is disturbing, unsettling, and saddening to say the least. This article will delve into the story, revealing some of the twists exposed along the way, so consider this to be your spoiler alert.

Facebook and YouTube were about five years old at the time, and this is around when social media posts, photos and videos began being coined as “going viral.” One such video was that of an unidentified male fatally harming kittens. As the video spread, a group started to band together online to try and identify the individual to put them to justice for their utterly heinous act. The team used clues evident in the background of the video footage such as doorknobs, electrical outlets, furniture, and even appliances to locate geographically where the videos were filmed. Eventually, another video surfaced of the same individual performing more atrocious violent acts on poor, defenseless felines. This, of course, drives the online group to double and triple their efforts in identifying the monster before he moves on to harm any other creature or, as history has proven, person. Various clues left by the animal killer leads the online team to discover his name and numerous social media fan pages containing photos of himself posing in exotic places all over the world, supposedly as some highly successful and handsome male model. Yet, something about some of the photos isn’t right. As more and more information is uncovered, and with the help of some of the photos, the elusive and always changing location of the man is identified, just moments too late, by architecture and roadways in the photos and GPS data contained in the metadata.

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Parked, but Watching


Laurence R. Penn, Forensic Animation/Video Specialist

A recently released video shows a car attempting to parallel park on a city street when suddenly the car speeds up in reverse, drives over a designated bike lane, and with the help of a ramped barrier, flips upside down, very narrowly avoiding a number of pedestrians as they flee the chaos. This is exactly the kind of thing that triggers my paranoia of eating at the outdoor seating of an unbarricaded restaurant sidewalk or pulling into the bollard-less parking spaces directly in front of my children’s daycare. Luckily no one was seriously injured.

What’s interesting in this case is the fact that this video was recorded on two cameras, located on the rear and side of a witness vehicle that was parked in front of the open spot. When you are walking down the city street, you pay no attention to the parked vehicles. Yet, they may be paying close attention to you. Even though this witness vehicle was parked and unattended, it was silently recording its surroundings, likely in many more directions than the video shows. The owner of the vehicle was then able to access the video at the time of the incident to provide it to authorities. Though it is not evidently clear why the driver gunned it in reverse, the dynamics of the incident are obvious in this case. We analyze video from many cases involving mass transportation vehicles such as busses and trucks which already have systems to record from cameras installed in multiple locations. While passenger vehicle manufacturers currently do not install multiple recordable cameras, that is undoubtedly soon to change and many of our cases will include analysis of this type of captured video in the future.

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Surveillance Cameras: Inside Looking Out

Laurence R. Penn, Senior Forensic Animation/Video Specialist



There’s a good chance an interior surveillance camera located close to a window will capture activity or an incident outside of the property it is primarily intended to surveil. Such was the case when a surveillance camera observing the entrance of a store captured a collision where a right turning truck collided with a cyclist traveling the same direction on a narrow city street. In fact, there were many cameras that captured the incident, including three cameras from two different businesses and the dashcam on the truck itself.

Videogrammetry techniques were used to camera match one of the surveillance videos to high resolution 3D scan data of the site. The truck was also documented, and its 3D data used to re-create a trajectory as depicted in the surveillance video. Videogrammetry analysis of the other cameras helped confirm the results of the vehicle tracking.

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Where the Lamp-Post Falls

Laurence R. Penn, Senior Forensic Animation/Video Specialist ::::


An old residential lamp post, weakened by a recent storm, fell unexpectedly and damaged two vehicles parked below. The owner of one of the vehicles claimed to have sustained injuries from the falling lamp post while entering her vehicle. The actual lamp-head was the part identified as the culprit for the injury.

However, the vehicles’ orientation and proximity to the post made the story difficult to comprehend. Three scene photos were camera-matched using photogrammetry, and as part of the process, the approximate position of the fallen post and lamp-head were calculated. The results were imported into 3D software and the arc of the falling lamp post was established.

When viewed from multiple angles, the reconstructed scene showed that the plaintiff was likely not in a position to be injured by the lamp-head, as described in the testimony.

Laurence R. Penn, Senior Forensic Animation/Video Specialist at DJS Associates, can be reached via email at experts@forensicDJS.com or via phone at 215-659-2010.

Virtual Reality Premieres at DJS Associates

Laurence R. Penn, Senior Forensic Animation/Video Specialist ::::


On Friday May 3rd, at the Forensic Storage and Technology Center, DJS Associates was proud to host a CLE approved Seminar, “Investigating Vehicular Collisions: An Interactive Seminar Where YOU Take Part in the Investigation” in which we discussed the many old and new ways of collecting physical and digital data for collision reconstruction, and how that data is used for analysis. The final presentation of the seminar demonstrated how a 3D reconstruction can be experienced through Virtual Reality, produced in-house by DJS Associates. With current real-time interactive 3D technologies, one can step into the driver’s seat and view the circumstances at the time of the collision to watch them unfold. The addition of our interactive steering wheel, pedals and hand trackers assisted in making the experience as immersive as possible for attendees.

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