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Sensing, imaging and IoT technologies

Home > Our services > Services and facilities > COVID-19: technologies to support workplace safety > Sensing, imaging and IoT technologies

The how, what and why of available technologies

The devices or solutions you choose to implement in your workplace will operate using a number of different technology protocols or communication standards.  In this section, we’ll look briefly at how each one works, potential application areas and possible drawbacks.

In their own way, products or services that use these underlying protocols or standards can help in  enabling, encouraging, enforcing and evidencing any new procedures and practices you decide to implement for your employees.

View our full guide to technologies to support workplace safety and please ensure you are familiar with the Scottish Government Routemap and the current situation for Scotland.

Factors to consider

When choosing the right solution for your challenge and working environment, you will have to consider the following factors:

Cost and functionality
There is a range of technology solutions at different price points.  What you choose will depend on your challenge and what you want to achieve.  Options range from simple implementation to quite sophisticated systems whose usefulness may extend to support other aspects of your business, perhaps in other health and safety areas; right through to higher concept solutions of connected networks that could help to deliver higher levels of IoT engagement to your company.

CENSIS and Scottish Enterprise can offer advice on what’s right for you.

Ease of implementation
Again, this will vary depending on what you want to do.  Some solutions might require sensors to be distributed to staff, e.g., a wearable device powered by a battery that is charged or replaced as required. Other solutions could involve the installation of radio beacons at carefully selected points, supported by centralised control software.

Capturing data

You need to think about what you want to record and when.  Do you need to capture information as soon as a colleague is too close to another?   Or would it be more helpful to record incidences  that were more than 15 or 20 seconds in length?

You may wish to record every incident for the purposes of contact tracing in the event of infection, or it may be enough for you to quantify how sucessfully physical distancing is being implemented.   If the system is able to record exactly where and when incidents take place, or who is affected, this could be useful to help identify and address problem areas or behaviours.

If individuals are identifiable and data is recorded, then GDPR must be considered. In some workplaces, staff may be more willing to accept a basic system that simply sounds an alarm and does not record information.

A construction site or manufacturing space may require more ruggedised technology than a typical office, so you may have to consider technologies that are suitable for hazardous or challenging environments.

For workplace challenges around physical distancing, you will want to use technology with an accurate detection range.  What you choose though will be weighed against other factors such as where it will be used (indoor or outdoor), battery life, technology maturity and cost.

Some solutions use Bluetooth Low Energy (BLE), which is low-cost and doesn’t consume much battery power. However, its method of estimating distance is not as accurate as other technologies, so it may not be ideal for situations where people are habitually working around two metres apart. The system may be either under-sensitive and ineffective or over-sensitive with alarms triggered regularly which could be annoying and could lead to employees ignoring warning sounds.

However, for situations where people are liable to cross each other’s path, it can be an effective way to remind workers who may stray ‘too close for too long’ to a colleague.

Solutions based on ultra wide band (UWB) wireless technology are likely to be more accurate but in real life scenarios it might still be difficult to ensure high accuracy.

An alternative approach might be to use video cameras and analytics to calculate the distance between people with an alarm could be sounded when a breach is detected. This can be quite accurate but requires careful set-up and calibration in each area and may be viewed suspiciously by the workforce.

Privacy and Data Protection
You may have to adapt your company-wide GDPR policies alongside any technology solutions you introduce to your organisation.  If individuals are identifiable and data is recorded, then GDPR must be considered.

Thermal screening

Thermal screening is used to measure the temperature of a body, usually the skin temperature of the face (and by inference, body temperature). If someone has a higher than average body temperature, it may indicate they have a fever (one of they symptoms of COVID-19).

Thermal cameras 
These work by detecting infrared light (IR). All objects emit IR radiation. If the intensity is high enough then this can be felt as heat. The hotter an object is, the more IR radiation it produces. A thermal camera has thousands of tiny sensors, which measure the amount of IR radiation falling onto them. These are called microbolometers and each pixel in the camera has one sensor. The signals are processed and fed to a display where the different signal levels are assigned a temperature value and a colour. The resulting picture is called a thermogram.

Thermal cameras can potentially scan a group of people rapidly, and can work from several metres away.

Thermal IR sensors (used in non-contact thermometers)
These work on a similar principal but rather than collecting IR light in an array, the light is focused onto a single detector (IR Thermopile), which converts the energy to an electrical signal based on the wavelength and the radiative energy of the light. These sensors are usually narrowband, meaning the light is filtered to a small band of wavelengths to avoid absorption from the atmosphere and detect heat from a single point.

Thermal sensors are used in hand-held, non-contact thermometers which are pointed at a person’s forehead from a distance of about three centimetres.

Factors which can affect thermal screening accuracy include:

  • Environmental temperature
  • Humidity
  • Gender
  • Age
  • Whether the subject has just been exercising or is out of breath

Manufacturers will often look to increase accuracy by use of additional environmental sensors, which adjust the reading, or by calibrating against a local “black-body” reference, which has a known IR radiance value (temperature).

There are also some solutions emerging, which aim to detect the temperature from images of the tear duct in the eye, as that is considered to be more representative of core body temperature.

Camera solutions

Camera technologies can help with physical distancing and can be colour or monochrome. Megapixel cameras are commonplace, with costs significantly reducing in the last ten years or so. Used in conjunction with ‘machine vision’ processing technologies, cameras can be used to recognise patterns with an image to identify objects and features, including humans.
Most camera solutions will capture images in 2-D, and so to be used for physical distancing solutions, they need to be mounted on a ceiling or a roof.

The distance from the camera to the imaging plane will affect the area of coverage (field-of-view FoV), and the resolution of the image. The image needs to be calibrated to convert distance in pixels to distance in metres.

Once this has been done the camera system can provide a signal, alerting if human-human distance is less than a determined value within the plane of the image or if the number of people in an area is greater than advised.

CENSIS can offer advice on camera techniques and help you discover if they are right for your workplace.

Bluetooth RSSI devices

Bluetooth and Bluetooth Low Energy (BLE) are wireless technology standards used for exchanging data between fixed and mobile devices using radio waves at 2.4GHz and have a range of tens of metres. Detection of the strength of these radio waves by an antenna from a device is often measured in RSSI (Received Signal Strength Indication).

For similar devices, from the same manufacturer, RSSI is measured crudely and will range from ‘Weak’ to ‘Excellent’ in a similar manner to the cellular signal strength received by mobile phones. The signal strength will be mostly affected by the distance of the emitting device to the receiving device. This is the basis of mobile devices being used for physical distance measurement.

The stronger the RSSI value, the closer the device.

Due to the nature of RF communications, signal strength can be affected by other factors in the environment such as:

  • Extraneous RF noise from other signals
  • Absorption or attenuation by physical objects (including the human body)
  • The orientation of antennae.

These can be mitigated to some extent by signal processing techniques but RSSI will always be a fairly crude estimate of proximity unlikely to be better than +/- 0.5 metres and more typically +/- 1m for devices in close proximity. Devices can be both emitters and receivers such that any device, in principle, can determine how close it is to other devices and alert the wearer by sound, LED or vibration.

A local supervisory system may also be used to determine patterns of proximity for devices i.e. which devices, how close, how long.

UWB RTLS wireless technology

Ultra Wide Band (UWB) is a radio technology used for short-range, high-bandwidth communications.

This works on the same principals as GPS but within the space of a room. Ultra-Wide Band (UWB) Real Time Location System (RTLS) is a wireless technology which uses short nanosecond bursts of radio impulses (3-10 GHz) from battery-powered tags which are measured by fixed electronic readers (or anchors) located around an area.

The readers use time-of-flight (ToF) of these pulses to accurately measure the distance from tag to reader.

If a tag is detected by 3 or more readers in an area, then the system can determine the position of that tag to within 10cm accuracy.

While the accuracy is extremely good and relatively immune from external interference, the downsides of UWB technology is that it is generally more expensive than Bluetooth-based solutions and more power-hungry. The measuring range between tags and readers is typically 10m.

For small areas, 3 or 4 readers may be enough but larger areas may need many readers. Whilst the tags are battery-powered, the readers are usually connected with cables.

Another variant of UWB RTLS technology eliminates the infrastructure associated with fixed point readers and instead uses the tags to range between themselves.

This solution allows the tag wearer to be alerted (LED/Vibration/Sound) when too close to another tag but does not measure the location of the wearer in the area. A gateway at an entry/exit point can be used for recording contact records and configuring the tags.

While this is more power-hungry than the solution with fixed readers, it does allow coverage of larger areas at a lower cost.

To improve battery-life, some solutions are starting to appear, which use Bluetooth for an initial distance approximation and then power on the UWB chip to determine exact distance.

What to do next?

You may have a few questions once you’ve read through this section, or have some ideas you would like to talk through.  Why don’t we have an initial chat about how your organisation can use technology to reduce the risks of COVID-19 in the workplace.

Business Development team

Scottish Enterprise
Digital Transformation Specialists team.
Tel: 0300 013 3385