Hello everyone, and welcome to this week's #TuesdayTip!
This is the final post in a three part-series looking at video surveillance and how it could be used in your books. The first post introduced some examples of CCTV and also dispelled some common myths. Last week focused on complementary technologies such as night vision and ANPR. Today, I want to look at some more recent innovations that may give inspiration for your work, including body-worn cameras, dashcams and Google Street View.


Body-worn cameras, public camera phones and dashcams
One of the biggest changes to policing in recent years is the proliferation of cheap, digital camera technology. Many police forces across the world have adopted the use of body-worn cameras for front-line officers. They are used for evidence gathering purposes, as a deterrent (the hope being that violent members of the public may think twice about assaulting a police officer if there is likely to be evidence) and as a way of protecting the police against allegations of misconduct. Of course, the opposite can also be true, with the body-worn cameras of some US police officers providing evidence of excessive violence towards un-armed suspects .
The rules surrounding these cameras' use, and the circumstances in which they are deployed, vary by jurisdiction and it is a rapidly changing field. You may wish to consider researching their use by a particular force if accuracy is important.
More recently, members of the public have taken to recording crimes and major incidents on their camera phones. Similarly, it is becoming increasingly common for drivers to fit dashboard-mounted cameras to their vehicles. They can be useful when establishing the facts of a road traffic collision, for example if the other driver is denying responsibility. Some insurance companies incentivise their use. Some cyclists also have helmet-mounted cameras.
However, these devices will often pick up other footage that may be used as evidence. In a recent murder case in the UK, a conviction was achieved, in part, when a neighbour who was parked a few doors down waiting to pick someone up, with their dashcam active, captured the victim's estranged husband coming out of the house where she was found murdered. The time-stamp on the footage established that he was at the house earlier than he claimed and it was subsequently proved that his alibi was false. 
It is now common for police to request any footage, in the same way that they will appeal for eyewitnesses.
Google Street View
I have included this as it is a technology that can be of use to police, but which is sometimes misunderstood.
The search engine giant Google, along with other mapping companies, started producing basic map data for integration with GPS in satellite navigation technology, back in 2005. Some years later, these companies, in particular Google, started commissioning high-resolution photography from surveillance satellites and (more commonly) low-flying aircraft. This allowed them to produce top-down photographs of much of the Earth's surface. By combining this with the pre-existing navigation and mapping technology, Google Earth was born. Users can put in an address, or place of interest, and see aerial photographs of that area. Resolution varies, but it's not uncommon to be able to recognise your house, and perhaps even the car on your driveway.
In 2007, Google went one better and started photographing neighbourhoods at ground level. They sent cars up and down roads with roof-mounted 360 degree panoramic cameras. Street View, allows you to virtually walk up and down areas and 'look around'. It is a great way of checking out a neighbourhood before visiting an estate agent, for example.


The police also use this technology. But it has important limitations. First, it is not the same as a spy satellite. The images used are often weeks, months or even years out of date. The police cannot call up Google Earth and look to see if a suspect's car is parked outside their house. That photo was probably taken months ago.
However, it can provide the police with the basis for intelligence gathering or planning. For example, they may be able to identify entry/exit points to a property, permanent outbuildings such as sheds that they need to search, or the fact that the house (at the time the photograph was taken) has no garden wall for the police to hide behind when sneaking up before a raid. It's not a substitute for proper, eyes-on intelligence gathering, but it can certainly help.


New technologies
Two emerging technologies that may be of use in your novel are Facial recognition and Gait Analysis.
Long a staple of Hollywood thrillers and futuristic novels, facial recognition is starting to enter the mainstream. Anti-terrorism units and the intelligence services are already able to identify faces in real-time from a database of 'persons of interest'. As the technology becomes cheaper, and cameras continue to proliferate in public spaces, this is likely to become more common. More recently, private companies have taken to using the technology to identify football hooligans, or intercept known shop-lifters entering shopping centres.
There is a vigorous debate over the legality of its use, its accuracy and privacy implications in a free-society. There are also questions over its accuracy for dark-skinned people, with suggestions that the historic tendency of developers to populate the system's 'training' database primarily with white, Caucasian faces leads to increased misidentification of people of colour.
The degree of access that the detectives in your novel will have to this technology is changing constantly, so consider if it is appropriate for your book to feature it. If you are unsure, you could always hedge your bets and have your detectives request its use, but perhaps be rebuffed by a magistrate refusing a warrant, or the video surveillance unit not having the resources for this type of case.
Of course the biggest obstacle in the current climate is the use of facemasks. Since some degree of mask-wearing is likely to be with us for the next couple of years, a person with their face covered in public will no longer elicit the same suspicion that it might have done.
Could your perpetrators use the current pandemic to their advantage?

Gait Analysis is a relatively new technology that forensic specialists have been developing. There are some who believe that the way in which a person walks (their gait) is a unique biometric that can be used to identify a person on video footage. This claim is contested by others who don't think it is as accurate as some would claim. Injuries, carrying a heavy bag, different shoes, taking extra care on an icy pavement... all of these factors might change a person's gait.
Needless to say, good quality video footage is essential for this purpose. The footage is analysed by a forensic podiatrist and is an example of an 'expert opinion'.
From a legal point of view, it hasn't been rigorously tested in the courts, so relying on it as the strongest piece of evidence against a suspect would be risky. There have been several appeals against its use in recent years. However it may still have some use in the police's investigation.
Imagine a scenario where a person is murdered in their workplace, out of hours. The killer is likely to be a co-worker (so they have legitimate explanations for physical evidence found at the scene), but everyone claims to have an alibi. Chasing down each co-worker would be a huge task for a large workforce. However, CCTV outside the building captures somebody with a distinctive walk (perhaps a limp?). The police then prioritise this person as a suspect.

Thank you once again for reading this far. As always, I hope that it has been useful, perhaps even providing inspiration for your own work.
Please feel free to comment here or on social media.
Best wishes,
Paul

Hello everyone, and welcome to this week's #TuesdayTip!
This is the second in a three-part post looking at video surveillance and how it could be used in your books. Last week's post introduced some examples of CCTV and also dispelled some common myths. Today I will focus on complementary technologies such as night vision and ANPR. Pop back next week for a discussion about some more recent innovations that may give inspiration for your work.

Night Vision
In recent years, the ability to see in the dark has moved from specialist, often military, applications to the mainstream. Peruse a catalogue of residential security systems and cameras with low-light or night vision are now the norm, even at the cheaper end of the market.
So I thought it may be useful to explain what this is and how it works. But first of all, I need to clear up a misconception.
Night Vision is NOT the same as Thermal Imaging.
I am sure everybody is familiar with footage from TV of police helicopters chasing joyriders in the pitch black, late at night. The miscreants typically end up crashing or abandoning their vehicle, before leaving on foot and trying to hide in somebody's back garden.
They can easily be seen as glowing heat spots against a cooler background. The police and dog teams chasing them are similarly visible. From above, the helicopter crew direct their colleagues on the ground towards their quarry.
Thermal Imaging (or 'Heat Vision'), works because all objects emit infra-red radiation. The intensity of this radiation, which is invisible to human eyes, varies depending on the temperature of the object. Human beings are typically warmer than their surrounding environment, and so they standout against the background. Heat-sensitive cameras can detect this invisible radiation, and will produce an artificially-coloured image that can be seen by the operator. The infra-red radiation can be blocked by buildings etc, but hiding under a tree or in a bush won't work.
This technology is also used by the military.

Night Vision also relies on Infra-Red.
Night vision, or low-light enhanced images also require infra-red, but work a little differently. Human beings can see a fairly narrow range of colours (referred to as wave-lengths, or frequencies). What we perceive as white light, or natural light, is a mixture of these colours.
When we see an object, what we are actually seeing is the light reflected from a surface that enters our eyes. Light moves in a straight-line from a light source, and is then reflected or absorbed by an object, and it is these reflections that we see. The more light that our eyes receive, the better we are able to see. This is why we see more clearly when we turn up the brightness on a lamp, for example.
However, because we can only see a relatively narrow range of wavelengths, the light that is invisible to us, such as infra-red, goes unnoticed.
In low-light systems, the camera is able to pick up this extra infra-red and, after adjusting its colour to make it visible to human eyes, adds it to the image on the screen, so the picture is brighter with more detail. Your mobile phone camera uses this trick to make pictures taken in dim light brighter.
This system is called 'passive infra-red'. It is simply collecting and using more of the light already available.

Active infra-red uses the same principle as turning on a torch or a light to see in the dark. If I want to ensure that a security camera outside my house gets a clear image of somebody entering my back garden in the dead of night, then the obvious thing to do is flood my backyard with a high-powered light. That light will be reflected off any objects it hits and return to the camera, in exactly the same way that natural sunlight is reflected during the day.
For obvious reasons, this is not desirable.
Active infra-red systems work by shining invisible infra-red light, and then capturing the reflected infra-red light on a low-light camera. Because the infra-red light cannot be seen, the area remains pitch-black. As IR is not a colour that our eyes can perceive, the computer-generated images are grey-scale (black or white).
The quality of the images generated can be variable. A close-up image of a person's face (such as a burglar!) can be good enough to allow them to be easily identified. Car license plates vary. Because the plates are coated in a reflective material, bright lights shining on them may make them unreadable, whilst paradoxically, those in shade may be more readable. I did a quick experiment and found that I was unable to read my own car's licence plate which is directly under the camera, but could see my neighbour's, which is parked at an angle to the camera.
How could you use this in your book? Could the police be chasing a suspect at night with the aid of a helicopter (thermal imaging)? How useful is the night vision on a security camera? Is it good enough to identify a suspect or will you decide that it won't stand up in court?

Automatic Number Plate Recognition (ANPR).
The system works by automatically recording the licence plate of a vehicle, which a computer will then read and store or use immediately. As the computer systems get more sophisticated, the need for human assistance to read strangely formatted or dirty licence plates becomes less necessary.
Examples of the system' use include:
Law enforcement. The police have access to large numbers of 'traffic cameras'. These may be fixed surveillance cameras mounted on poles over roads or traffic lights, or mobile cameras attached to the dashboard of police vehicles.
Local Councils. They can be used to help enforce civil penalties, for example monitoring the use of residential parking permits.
Commercial operators. These might include councils, but would also include the owners of car parks - increasing numbers of car parks photograph the licence plate of cars entering and leaving and use this to calculate parking charges. Other uses of ANPR include filling-station forecourts, to deter and capture  fuel thieves.

What happens next depends on the context in which it is used.
For the police, the system might be tied in directly to the Police National Computer and systems such as the Motor Insurance Database. Cars that are associated with persons of interests or active investigations may then be identified, as would cars being driven illegally without insurance etc, or stolen vehicles.
The camera network can also be used to track a vehicle's journey - either retrospectively, to work out where a vehicle has been eg when trying to solve a case - or in real-time, if the police are trying to find an suspect in an ongoing situation.
For a car park, the system would usually be completely closed. The computer simply notes that a car entered, then notes the time that it left. If the police want access to that information, to either track down the whereabouts of a suspect or to determine if they were parked in that area at the time of an offence, they would have to ask the operators. Many car parks are operated by the same company, eg NCP, so a request for information can be applied to all of their properties.

For parking penalty enforcement, the operator would submit registrations for vehicles that they believe have infringed the rules to the DVLA (Driving and Vehicle Licencing Agency), who would then give them the details of the registered keeper which the operator will then chase down.

That's it for this week. Next week, I will conclude this mini-series with a look at the future and some other uses of video surveillance technology, such as body-worn cameras, dashcams and even Google Street View!
As always, feel free to comment here or on social media.
All the best,
Paul

Hello everyone, and welcome to the first #TuesdayTip of 2021!
This is the first in a three-part post looking at video surveillance and how it could be used in your books.
The articles will look at Closed Circuit TV (CCTV), Automatic Number Plate Recognition (ANPR) and dashcams, as well as more sophisticated applications such as night vision, body worn cameras and gait analysis. I will also highlight some of the myths perpetuated by TV and movies.
For brevity, I will usually just refer to it as CCTV, unless detailing a specific application.

Scale and History
The term Closed Circuit TV is simply a way of distinguishing between video that is broadcast widely and indiscriminately (eg television programmes) and video that is intended for 'private' viewing purposes and is not publicly available.
CCTV of some description has been available from as early as the late 1920s, when it was used to monitor the comings and goings of visitors to the Kremlin. In the 1940s, the Nazis used CCTV to remotely monitor the launch of V2 rockets. From the 60s, it was used as a precursor to pay-per-view services - for example broadcasting sporting events to paying audiences in select theatres.
Today it is widely used by governmental organisations, private companies and individuals for purposes ranging from security and law enforcement (criminal and terrorist activities), safety (monitoring motorways or public areas for accidents or potential accidents), efficiency (workforce monitoring, for example in factories and warehouses), evidence collection (police body-worn cameras or dashboard cameras) and deterrence (there is good evidence that burglars will favour properties that don't have CCTV). Schools may use CCTV to deter and monitor vandalism and poor behaviour and even the quality of teaching. Care homes also use CCTV to monitor the health and wellbeing of residents (and there have been upsetting incidences of staff abusing patients caught on camera). Video-enabled baby monitors (or 'NannyCams') are increasingly used by parents to keep an eye on their offspring (or even pets, when they are out at work!).


Estimates vary enormously, but it is believed that the UK has the highest number of cameras per citizen - state-run and privately-owned - of any country in the world, including totalitarian and police states. Residents of large cities going about their day-to-day business may be caught on upwards of 70 different surveillance cameras each day!


The first applications were live only; there had to be a person monitoring the camera feeds at all times. With the advent of video recording equipment, footage could be saved for later retrieval. Multiplexing allowed multiple camera feeds to be recorded at once, and the technology shifted from analogue recordings on cassette tape, to digital recordings on tape, to digital recordings on computer hard drives and more recently, cloud-based storage. Many modern systems allow the camera feeds to be watched remotely via the internet.
Some systems have been criticised for poor security; for example broadcasting feeds over the internet with poor encryption, or easily-guessed passwords. This allows unauthorised access to what should be a private feed. How could you use this in your book? Could malign individuals use this to help them plan a crime or keep tracks on someone (for example a stalker or sexual voyeur), or could law enforcement exploit this to monitor a suspect?


Dispelling Myths
The ubiquity of surveillance can make one wonder exactly how a crime writer can go about setting a crime in a large city, without their perpetrator being caught on camera, identified and arrested before the end of the prologue - but fear not, there is no need to move your novel to a remote island or set your books no later than the end of The Second World War.


The quality isn't always that good. We've all seen it; blurry, pixelated images or videos released by the police in the hope of identifying a suspect. How often have you looked at black and white images and found yourself just taking the police's word for it that the indistinct shape is even a person, let alone somebody you may recognise? The haunting images of the toddler Jamie Bulger being led away to his death by two young boys in 1993 were full colour, but other than identifying the colour of their clothes, probable ages of the two suspects and the time that they snatched him, the evidential use of that footage was more in establishing the events that happened than directly identifying his kidnappers.


For video footage, older systems in particular used lower frame-rates to squeeze more hours onto the recording media, therefore the video is jerky and the suspect may only appear in one or two frames.


Obviously, the specialist officers that spend their working days staring at such video are more practised than you or I, but sometimes you wonder how useful releasing such footage might be. However, the human brain is a funny thing, and whilst a stranger might not see anything of any use in such images, somebody familiar with the person on the screen may see something they think they recognise. Sometimes that's all that is needed; another name to throw into the mix. The police can then investigate that person and either eliminate from their inquiries or perhaps dig a bit deeper to find more compelling evidence.


Of course, modern cameras are light-years ahead of what was available even ten years ago. A couple of hundred quid can buy a high-resolution, full-colour system that can record easily-identifiable images, even in low-light. You can even buy smart doorbells that record footage of anyone ringing your bell, or can be triggered by anyone stepping within the camera's range.


Could your book feature a suspect caught near an area by a neighbour's CCTV? Although this is not evidence that they committed the crime, could it be used to prove or disprove an alibi, or show that they had the opportunity, as they were in the area at the time?


You can't zoom in. Contrary to what Hollywood would have us believe, you can't just 'zoom in' or magnify an image to gain more detail from previously-shot footage. Whilst specialist technicians may be able to 'clean up' images, removing static or adjusting the colour, ultimately, the laws of physics come into play. The recording can only display information from the photons of light energy that the camera picked up at the time.
Take a car licence plate - if it is blurry or too small to read on the original image, then no amount of enhancement will magically make it readable. Images that are borderline might benefit from interpolation, where complex computer algorithms can 'guess' what some of the missing pixels may look like, maybe by comparing several different frames from a video, and perhaps using other sources of information to confirm those guesses (eg comparing the shape of the reconstructed image to a database to work out what the digits are most likely to be), but the options are limited.


Could blurred footage collected at the beginning of a story be used by your detectives later in the book to strengthen the case against a suspect? Could you use the need to send a tantalisingly blurred photo off for specialist enhancement as a way of controlling the pace of your story? 


Video that has been recorded over is permanently destroyed/can be retrieved at will
This subheading appears contradictory - and this is deliberate. Most video systems have a finite amount of storage. Typically, they are configured on a 'rolling basis'. When the recording media is full, the system copies over the existing footage, replacing the oldest footage first. So even if a CCTV unit has been running for twelve months, there may only be the most recent month stored on the system. And as it continues recording, the older footage disappears, so that only the most recent month is on there.
Data Protection laws also dictate how long security footage can be kept for. For example, your local supermarket doubtless records customers throughout the store. Their data protection policy will determine how long they can retain that footage before they need to delete it. The exception of course is if they have reason to suspect that there is evidence of criminality etc on a particular piece of footage; then they are allowed to keep it until it has been used in court etc.


Whether this deleted/written-over material can be retrieved depends on the system used, how many times that tape, or that hard-disk sector has been over-written, the quality of the recording material etc. Forensic specialists might or might not be able to revive footage of sufficient quality to be any use.
As a writer, this ambiguity is great! You can decide whether or not your story needs the footage to be retrieved and then write accordingly.
'Sorry, Sir, the footage has been recorded over too many times, we can't bring it back'.
Or
'We managed to retrieve some of the deleted footage, you can clearly see the suspect's car.'


If you write it confidently, avoid naming specific systems or tripping yourself up with technical details, your readers will accept this. It helps if you foreshadow this when you hand it to your forensic specialists.
'Robertson looked at the CCTV unit dubiously. "No Promises, Sir, this system does a really good job of erasing older footage."'
 
In this post I have only touched upon the basics. Next week's post will delve into the subject in more detail. I will cover night vision and Automatic Number Plate Recognition. The concluding article will discuss some more recent innovations that you might find useful when writing your novel.


Until then, thank you for reading this far. Feel free to comment here, or on social media.
Best wishes,
Paul