Category Archives: Forensic Workflow

Body Worn Cameras (BWCs) as a Silver Bullet, Vol 4: Impact on Society

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In our previous posts, we have mainly focused on technical issues, but to do this topic justice, we need to address the social and ethical issues as well.

Trying to predict how the use of BWC technology will impact society and ethics, in general, is very difficult, but we can ask a few questions that can stimulate thought on the subject:

  • When should these cameras be deployed or how invasive should they be permitted to be?
  • Can an individual request the officer to turn off his camera in his own home or should the officer be allowed to overrule that choice if he feels it could provide a benefit in safety for one or both parties?
  • Would that individual be given access to that video? And if so, how will that data sharing take place and how much would it cost?
  • Will the police use of this technology set a social precedent and will we see this technology spread as a result?
  • How will access to all this data change the way we feel about privacy in general?

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Body Worn Cameras (BWCs) as a Silver Bullet, Vol 3: Storage

bodyworn-794100_640If we take volume 2 into account and apply correct scientific post-processing to our BWC footage, we now have usable video evidence but there are some further issues:

  • How will it be stored?
  • How much will that storage cost compare to the cost of not having this evidence?
  • What is the stance police departments will take on data protection and how will society respond to being further surveilled and having that surveillance stored?

This large-scale data collection has huge storage requirements, an example, pre BWC adoption: “In December 2012, IDC and EMC estimated the size of the digital universe (that is, all the digital data created, replicated and consumed in that year) to be 2,837 exabytes (EB) and forecast this to grow to 40,000EB by 2020 — a doubling time of roughly two years. One exabyte equals a thousand petabytes (PB), or a million terabytes (TB), or a billion gigabytes (GB). So by 2020, according to IDC and EMC, the digital universe will amount to over 5,200GB per person on the planet”. (Ref. http://www.zdnet.com/article/storage-in-2014-an-overview/) This is likely to increase as the BWC option becomes more widespread across the globe. Continue reading

Body Worn Cameras (BWCs) as a Silver Bullet, Vol 2: Quality

Volume 2 in our series on Body Worn Cameras.

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Let’s go through a thought experiment: we are a police officer about to enter into the pursuit of a suspect. Fortunately, in some cases we may not need to manually turn on our BWC because it has been programmed to do so upon sensing movement and other triggers. We begin running after the suspect and when we are close enough to the suspect we draw our service weapon and begin the process of arresting them.

Okay, how would this video look when viewed in court? First of all the video will be very shaky and due to the rolling shutter effect possibly distorted. “Rolling shutter is a method of image capture in which … each frame of a video (in a video camera) is captured not by taking a snapshot of the entire scene at single instant in time but rather by scanning across the scene rapidly, either vertically or horizontally. In other words, not all parts of the image of the scene are recorded at exactly the same instant”

 

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CSI Video Enhancement, Finally Someone is Getting It

I am finally starting to see some articles which explain nicely what we have been trying to explain for a long time, regarding the video enhancement techniques that you see in CSI-type shows.

I just discovered a very nice article on How to Geek: Stop Believing TV’s Lies: The Real Truth About “Enhancing” Images. I already tried several times, even with our most recent blog post “The Untold Secrets of Forensic Video Enhancement: Myth versus Science”, to explain what is feasible and what is not feasible for enhancement, but the How to Geek guys do an even better job.

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I just want to cite and comment on a few parts, that I really like:

It’s one of the most common tropes in television and movies, but is there any possibility a government agency could really have the technology to find faces where there are only blurry pixels? We’ll make the argument that not only is it impossible with current technology, but it is very unlikely to ever be a technology we’ll ever see. Stick around to see us put this trope under the lenses of science and technology, and prove it wrong once and for all.

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The Untold Secrets of Forensic Video Enhancement: Myth versus Science

So you are probably reading this blog post because you have been watching too much CSI (Enhance! Uncrop! Flop!) or because you have tried Amped FIVE on your crappy DVR video and weren’t able to obtain the miracles that you can see on our samples page.

The point is that we don’t do miracles, we are just scientists. We work with number sequences that incidentally happen to represent some visual information called image or a signal called video.

Some people may even wonder if the images on our website’s samples page are fake and we artificially introduced defects on good images in order to show how the software works. We assure you that what you see are results of real pictures or video, most of them have been taken by myself to reproduce typical situations you will find working in forensic cases and with CCTV videos. Of course we are not going to put on the web confidential and personal data belonging to real cases that we receive from customers or that we are asked to analyze. We are a professional company, we keep those cases strictly confidential, so they never would appear as samples.

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High FIVE for Spreadys!

Our friend David Spreadborough, better known as Spreadys, has written a bunch of articles on different DVRs he tried at IFSEC 2014. The articles are packed with a lot of very useful technical insights, which system producers should take as a checklist to improve their products.

The good thing for us is that (as Spreadys notes) most of the proprietary video files produced by these systems are easily reproducible with Amped FIVE. Continue reading

Forensic Image and Video Analysis: The complete workflow.

Amped Software is a pretty young company, but we have had the opportunity to work on almost 400 cases. We are mostly focused on software development, but from time to time, we are asked to work as expert witnesses for some major cases or we are asked by our customers to help them by evaluating (more or less informally) their material and providing some consultation.  These external cases have allowed us to see that there are steps that are commonly missed and others that are rarely taken into account in practical forensic video analysis.

Today, speaking to an agency about a potential project, I realized just how broad and complex the complete workflow process is for our (and our users) job.

If we think about all the tasks related to analysis, it can be really overwhelming.  To stay on point, I usually list on paper all the possible steps we need to take to do a really complete analysis.  This way, I can stay organized and minimize the possibility of skipping or missing steps.  Also, if I do have to go to court, I have my outline that serves the basis of my presentation.

We always need to remember that our job doesn’t start and end with viewing and enhancing a video.  It’s more complex: we must ID the data, decode it properly, document the process, compare it with other material, and then go to court.  Since digital data is really just a collection of bits, we outline our process around working with these bits and answering key questions relating to what we need to do with the bits. Continue reading

Some thoughts on analog video tampering

Despite all the hype over digital technologies, anyone who works in forensics and video surveillance knows very well that analog video is still alive. It’s dying, of course, but sometimes you will still have to digitize old VHS for two reasons:

  • The source is a surveillance VCR that is still working (it hasn’t been replaced yet)
  • The source is from an old case (I’ve been found myself working on cases spawning from the eighties to yesterday)

Of course, it does not happen often (at least to me) to work in VHS;  but it happens.  I’m usually happy since it sometimes leaves more room for processing than super compressed digital videos so widely used today.

However, in this post I will speak of a more specific thing related to analog: tampering.

In the last year I’ve been working on three forensic cases where there was the strong suspicion of working on video material that was not original. The interesting thing was that all of this cases the suspicion was confirmed to be true. The cases were very different: in one case I had some avi and audio files, in one case a MiniDV cassette (digital), and in another case a VHS tape. Continue reading

What’s the problem with this license plate?

I find myself analyzing new surveillance videos almost every day, and in most of the cases I can either solve the problem very quickly or understand (even more quickly) that there is no information to recover in the video.
In special cases, where something very specific and strange happened; or the problem is very complex it can take a lot of time.

As always… Pareto principle: you solve 80% of the cases in 20% of the time, and, well, 20% of the cases takes 80% of the time.

In my own work probably the right numbers are 95% to 5%, but the idea holds.

With my experience on several thousands cases, I can estimate whether an image or video contains some information and it’s worth processing, or not, very quickly. I usually do a couple of tests, just to be sure of my first glance and sometimes I get surprised by the power of the algorithms; anyway, usually you can tell quite fast if you will get something from a video. Continue reading

Processing a video in a proprietary format with CamStudio [How to]

One of the biggest problem during investigations on CCTV footage is the fact that most of the systems records in some proprietary format. Although usually encoding algorithms employs the standard mpeg-like algorithms, you won’t be able to view them on common media players. Some are providing a DirectShow or VideoForWindows codec, but most of them allows to view the recorded material on some custom media player. If you want to try to process the video with Amped Five (or some other editing software, I hope not), you’ll need to capture directly what’s happening on screen and encode it back with a more standard codec. Some of these players have some options to save the frames of the video in image files or to export it in the avi format, but quite often you have to save manually all the single frames one by one (what will you do for hours of video?) and the avi file exported will be very badly compressed, further damaging footage that proabably was having a bad quality.

Here it comes in help a beautiful free tool, called CamStudio. You can download the program from here. A very important thing to note is that you need also to recompress the captured video (your hard drive won’t be big enough if you nedd to record more than few minutes) with the minimum loss of quality. For this purpose the CamsStudio author makes available also a lossless codec to install on the system, that you can download here. In the last days the website wasn’t accessible because of traffic limits, but you can still access it by SourceForge.

CamStudio screenshot

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