Category Archives: Press / Media

Video Evidence: Handle with Care

Some of the new simplicities afforded to us can, unfortunately, cloud ones’ judgement when dealing with images and video for legal use.

Technology has, in most parts, made things incredibly easy. Take the example of photographs and video. We all now love to quickly snap a memory or record some footage of an event. We can adjust the colour or light, crop out unwanted parts, or trim the end of a video. It’s then a simple click on the share button to immediately have that sent to friends or family via a messaging app or social media. 

Some of the new simplicities afforded to us can, unfortunately, cloud ones’ judgement when dealing with images and video for legal use.  Why do it one way, when it’s so much easier to do it another, perhaps quicker way?

In late 2016, at the conclusion of a trial in Nottingham Crown Court, for four men involved in the murder of Aqib Mazhar, Judge Rafferty stated, “there must never be another case in this country where those analysing CCTV don’t have the best equipment.” The quote stems from the fact that it wasn’t until the trial had started that video material was properly reviewed and that significantly changed the weight of the evidence.

Whether it is CCTV evidence, mobile phone video or a sequence of images, the software used to review that evidence can alter the viewer’s interpretation. It could be that the player drops or misses frames. The player could present the video too dark, or too light. The player could change the shape and size of the image or video, resulting in objects appearing smaller or larger. Many surveillance system players alter the image to make it look better, even though that is not what was originally recorded – scary, but true.

In 2015, a conviction of Indecent Assault was overturned at the Court of Appeal. Mr Mohammed Islam was earlier convicted at Flintshire Magistrates Court, where a CCTV image of a vehicle, alleged to be his, was used as evidence. After analysis and enhancement, it was proved not to be his vehicle and his conviction quashed. Mr Islam’s lawyer, Adam Antoszkiw, later stated the crucial evidence was not properly examined because of financial constraints.

Multimedia evidence, especially CCTV or low-quality mobile phone footage must be handled with care. 

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Using Enhanced Images in Court

I recently testified in court as a forensic image and video expert and, as is sometimes the case, the use of some filters to enhance images was questioned. As I have written before, there is some processing that should be entirely avoided, since it lacks accuracy and repeatability. For example, we should avoid techniques which add new information relying on data obtained by a training set, or techniques which have a random component.

Some years ago, there was a school of thought that said, only classical image processing techniques available for the analog photography can be applied to digital photography in the forensic context. What are the risks of applying the wrong processing? We are not interested in having a “pleasant” image, we are concerned about extracting information from it. The risks of wrong processing are:

  • Removing existing information: for example, removing the grain in a dark image can remove also important details.
  • Adding new information: for example, creating or amplifying image artifacts which may be misinterpreted as a real detail.

In this reasoning, we are not referring to details at the pixel level, but at the image semantic content. In general, if I resize an image, I add a lot of new pixels but if the processing is correct I am not adding any new relevant information.

It’s important to understand that most of the image processing techniques present a compromise: I enhance something at the expense of damaging something else. For example, if I lighten an image to show better a dark part, it’s very likely to lose details in the parts of the image that are already bright enough.

For this reason, it’s very difficult, in general, to say which techniques are good and which techniques are bad. Their applicability must be related to the specific case and the parameters used. Filters are just tools, and as such, they can be used in the right way, obtaining better images, or in the wrong way, damaging the image quality or presenting wrong information.

Because of this, it’s important not to blindly apply different enhancement and restoration filters, but to apply them in order to correct a specific defect. Similarly, the tuning of their parameters must be consistent with the amount of defect I want to correct. Abusing the filters can create images which are much worse than the original.

It is therefore important, as I’ve said many times, to work with experts who have specific experience in the forensic image and video analysis field. Who know what to do, and how to identify what has been done incorrectly.

A lot of pressure may be put on the processing done by the experts, but most people ignore that there are many other processing and possible issues happening during the image acquisition and visualization phases.

A lot of processing happens in the camera itself, from CCTV to smartphones. Unless raw image pictures are used, and this is very rare, the value of the pixels in an image are hugely dependent on the processing and encoding which automatically happens inside the device to obtain the ratio between image quality and technical limitations that the producer wished to obtain.

And then, even to simply visualize the image, there’s a lot going on under the hood. Different software can decode the image in a slightly different way which can enormously impact the final result, and a lot of image processing happens on the graphics card of the PC, on the screen, or on a projector. Just play with the brightness of the projector to realize how much the visible information in an image can be impacted by such simple tuning.

There is then the most critical part of the processing: our eyes and our brain. Different people see and want to see different things in the same image. Analyzing things in an objective and unbiased way is often very difficult unless you can measure things numerically. And in fact, avoiding and limiting the various types of biases are one of the most important aspects of forensic science currently studied.

This article, written by Martino Jerian, was originally published in Lawyer Monthly magazine. Click here for the published article. 

CCTV appeals: Don’t underestimate the importance of image quality

‘Caught on CCTV’ — how many times do we read or hear those words?

With cities worldwide sitting under the gaze of millions of public and private cameras, it is no wonder that in many cases, the best chances of identifying an offender starts with the image caught on CCTV.

But, the simple task of getting an image can sometimes be a challenge so it is no wonder that people look at the shortcut and simply take a picture of the CCTV monitor with their phone. It’s quick, simple and you immediately have an image.

This is great when recognition is time critical. The image of the ‘man in the hat’, the 2016 Belgium terror suspect, was first released after a snap of a CCTV screen. Then, a few days later, the forensically acquired evidential images were released.

When something is not time critical, then the correct acquisition of the original video will help immensely in any integrity or authentication issue. Not only that, but if any restoration or enhancement is required, then you will have a much better chance of image recovery.

Faces and vehicle licence plates are often requested for recovery. They have two matching characteristics – high detail. It is these high details that are lost when a piece of CCTV is captured incorrectly, snapped from a PC screen, re-recorded with the analogue video output, or obtained any other way that changes the original digital structure.

An added problem with some of these processes is that small details can change shape and become blended together. Letters and numbers on licence plates start to look like other digits.

It can be frustrating to use multiple pieces of software with a need to ensure no loss of quality during every stage. This obviously adds extra and unnecessary time to the workflow. Time that is extremely valuable in today’s policing environment.

A by-product of using Amped FIVE, the ‘all-in-one’ solution, is that investigative decisions can be actioned much faster. “Am I going to get something from that?” If the answer is no, then it’s time to move on. Spend the time on what is achievable and negate the impossible.

If there was not a correct acquisition of this original video, it may not have been possible to enhance the dark image to recover the details of the vehicle and license plate.

Licence plates usually stay within the policing world but faces, clothing configurations, and tattoos regularly end up in the press, social media, and within online galleries for recognition.

Therefore, it’s worth taking a bit of time with these to ensure the highest possible chance of some good intelligence. It can also avoid some embarrassment – reading through public comments on a few sites makes for painful reading due to the image posted being so bad!

Read the full article originally posted on Police Oracle.

There’s More to an Image than Meets the Eye

When using an image as evidence during a court case, the point of view it represents acquires a resonance much stronger than the testimony of a witness. With video, this is even more true, as we may understand the dynamics even from the frames and any additional information which may be gleaned from the audio track.

Nowadays, there are many free and easy tools which can be used to modify pictures with ease, and thus the authentication of images is of paramount importance. But even more importantly, we need to understand how much data there is in an image, in addition to what we can already see.

Read the full article published in Lawyer Monthly.

Digital images – trust must be earned

The science behind forensic image analysis is growing fast and constantly evolving. Even within the last 5 years, the ability to take a photo, manipulate it to tell a different story, and circulate the misinformation online has become infinitely easier. The advent of smartphones, convenient digital image manipulation software and easy dissemination of information are throwing up new challenges that investigators and forensic technicians must adapt to.

Unfortunately, it is too risky to simply take digital images at face value. Instead, we must ask and have the tools to query, such as “Where did the image or video originate from?”; “Who provided it and is there any reason they might have modified it?”; “Is it a camera-original?”; and “Do I believe this is a true and accurate representation of events?”

To give a practical example, back in the summer of 2017, two images featured prominently in the initial reporting of Hurricane Harvey. The first was of a shark swimming along the Houston freeway. The second showed several aeroplanes virtually underwater at what was claimed to be Houston airport. These iconic images were circulated widely on Twitter and were featured on mainstream national media such as Fox News. There was just one small problem. Neither situation had actually occurred!

If this behaviour is widespread on social and traditional media, then why shouldn’t we believe it is also impacting police and legal investigations? After all, if members of the public are prepared to manipulate images for the sake of a few likes and retweets, what will they be prepared to resort to when the stakes are much higher?

Read the full article published in eForensics Magazine.

 

Fraud in Science: the Bigger Picture

Cases of fraud within published scientific research are on the rise, with several recent cases involving the falsification of images.

Scientists are subjected to exactly the same pressures and temptations that drive people to commit fraud in all manner of environments and for various reasons. Sometimes the motivation is commercial; perhaps to obtain a research grant or to enhance the profile of the institution and attract more applications. In others it might be professional; to get published in a prestigious Journal or simply to save face after an experiment has failed to deliver the desired
results.

Regardless of the justification, when these actions have legal consequences it is important to have the tools to detect when such fraud occurs. And more importantly to have the ability
to scientifically prove this in a court of law.

Multimedia forensics is invaluable within cases of research fraud, both for presenting a case or defending the accused. However, it’s not good enough to simply bring in an expert witness and have them confidently present their case. Tools exist to carry out the analysis in line with the scientific methodology, giving the judge and in some cases the jury, a basis upon which to evaluate the full weight of the evidence. Consider it ironic, but if the right software is adopted within the legal system then the scientific method may just prove to be the answer to the current crisis facing scientific integrity.

Read the full article published in The Barrister.

All is not as it seems

Digital images are frequently used to provide supporting evidence within papers and reports, yet are not routinely submitted to any scientific process of authentication. In a world in which the tools to digitally manipulate an image are freely available, it’s no longer acceptable to simply take these images at face value.

The past 12 months has seen the scientific community rocked by a series of scandals relating to the use of manipulated images within published scientific research.

Researchers’ ambition to gain scientific exposure, to achieve career advancement or to secure funding, can drive them to embellish their results in order to attain their goals in the increasingly competitive world of scientific discovery. Equally, the pressure to publish can see them stumbled across doctored images and incorporate them by mistake. In these cases, not only is the individual’s reputation at risk, but also their colleagues’ who are oblivious to the altered nature of the images. The impact of these images is extensive and far-reaching: they threaten to endanger the name of the organization for which the researcher is working, as well as calling into question the integrity of the scientific community at large. This is a critical issue in the current technological day and age, yet very little is being done to address it. Bearing in mind the damage that doctored images can do, scientific publishers and research institutes ought to be more rigorous when setting out the requirements for images that are used in papers.

If some basic screening were applied more extensively to scientific publications, with minimal effort we would be in a much better position to guarantee, or dispute, the authenticity of images within scientific papers for the benefit of science and its wider community.

Working to detect image manipulation in the world of science is a long-term battle, just as it is in photojournalism, forensics, and in any other field where image manipulation is a growing threat to the veracity of images.

Read the full article published in Laboratory News.

Image And Video Forensics In Court: Forensic Science Is Not Forensic Fiction

Images and videos are some of the most compelling forms of evidence that can be presented in a courtroom. Yet it is important that the steps we take when preparing them stand up to scrutiny.

Within the field of forensic image and video analysis one of the biggest issues we face is the CSI effect: the phenomenon whereby representations of forensic science on popular TV shows gives a distorted perception of what is possible; from endless zooming from satellite imagery to enhancing the reflection of a reflection of a reflection. We very often have to explain, even to “the experts”, what is science and what is fiction.

Enhancing images for forensic use is not just about trying a few sliders and combining filters until you see something better. Are you confident the images you present within a legal investigation would stand up to scrutiny? And do you have the procedures in place to challenge digital evidence introduced by other parties?

Read the full article published in Lawyer Monthly.

Why investigating digital video is such a ‘huge pain in the proverbial’

With CCTV probably being the number one piece of digital evidence used in cases, many officers will have asked questions like, how do I get the footage; why is it not playing; or how can I get an image? It’s important therefore to understand why we have ended up here. Why digital video, specifically from the surveillance industry, is such a huge pain in the proverbial!

As computers and digital video started to creep into normality, the surveillance companies started to think of ways to say, and prove, that they were better than the other. One of the easiest ways to do this was to use a bespoke recording method and format, to suggest that it was better than the other. This is where it starts to go pear-shaped.

Very quickly we ended up with non-standard video files, requiring a player that could not install on a Force computer, with no method to interrogate, analyze, validate or process the evidence as required by the investigation.

It has been nearly 20 years since the start of Digital Video Recorders, and you will be glad to hear that things are improving. But, it is going to take a long time for many of these poor systems to get replaced by ones that are fit for purpose.

Read the full article published on Police Oracle.

It’s time to get real about fake imagery

As technology has enabled mainstream, widespread image manipulation, it is not surprising that there has been a huge increase in the number of tampered images which find their way into a wide spectrum of industries and sectors. Incidents of doctored images frequently appear in mainstream media where they incite cries of “fake news”.

For example, a photo at the G20 summit this year featured a photoshopped president Putin, giving the impression that he was colluding with president Donald Trump.  The photo proceeded to spread like wildfire across the internet, instigating huge political ramifications from a digital fabrication which would have taken a few minutes to create on a laptop. Last August also showed our vulnerability to tampered photos, with the circulation of a photoshopped image of a shark swimming up the freeway during hurricane Harvey indicating a larger problem with major international news outlets spreading the image as genuine.

Equally there is significant evidence of doctored images being used to support fraudulent scientific research internationally. Doctored experiment results and images continue to rock the research industry with every new fraudulent revelation.   A prominent cancer research scientist in Italy has been under investigation for using a photography studio to manipulate images pivotal to the crux of the “ground breaking” research. Indeed, the journal Nature has suggested that up to 1 in 5 scientific papers contain evidence of some sort of manipulation.

It is clear therefore, that when the stakes are high enough, people will manipulate the truth, and unfortunately given our tendency to trust photographic images, it seems that it is currently worth their while to do so. When the stakes are as high as imprisonment, it is easy to see how tempting it may be to manipulate an image to support an alibi or a particular version of events.

Unfortunately, security investigations are by no means immune to this phenomenon either. In fact, given the increase in the sources of digital images, the integrity of evidence in such investigations is at its all-time most vulnerable. Body worn cameras, smart phones and increasingly sophisticated CCTV surveillance means that investigators are now dealing with a fast-growing pile of unverified evidence.

Read the full article published in The Intersec Journal of International Security.