Mitigating Infection Risk from Touchscreens with Time of Flight Gesture Recognition


Image Credit: Noel Biesecker/

The ubiquity of touchscreens in public places, and in controlled environments such as hospitals and research labs, presents an opportunity for infectious pathogens to transfer from person to person. In this article we assess the risk of disease-transmission via touchscreens; and look at how replacing touchscreen controls with touchless gesture recognition, enabled by low-cost Time of Flight (ToF) sensor technology, can eliminate this risk on some occasions.

Although the danger may not seem pertinent at first, the ever-growing presence of touchscreens in everyday life means they are becoming a disease vector of increasingly significant proportions.1 Touchscreen technology has become a simple, low-cost, do-it-yourself alternative for many tasks that were previously carried out by personnel: Airport check-in desks, ticket machines in cinemas and train stations, self-checkouts in supermarkets, and reception desks in a hotel and office lobbies are just a few examples.

Enabling customers to carry out these tasks via touchscreen, in most cases, expediates simple processes and has proven convenient for companies and customers alike. But the price we pay for this increased convenience is that these screens become a resting place for a slew of bacteria and viruses accumulated from thousands of unwashed fingers, enabling them to be efficiently transmitted from one person to another.

The risk becomes more apparent when we start to consider touchscreens in settings where hygiene is of increased importance. For example, most fast-food restaurant chains now implement touchscreens for ordering in many of their branches. Patrons may not think twice about touching such a screen and then eating fast-food with their hands – but research from London Metropolitan University caused a stir in 2018 when it published a list of infectious and harmful bacteria found on the touch screens in nearby McDonald’s restaurants, including staphylococcus which can cause serious symptoms if ingested.2

These screens are regularly cleaned, of course, but to clean the screens after each use would be unfeasible. With one study of 3,749 adults in an American college town indicating that 43% of people don’t wash their hands with soap after using the bathroom, rigorous hygiene control of a touchscreen in this environment is essentially not possible.3

Touchscreens are also commonplace in healthcare environments including pharmacies and hospitals. Due to the increased importance of infection control in these environments, these are naturally subject to meticulous and regular cleaning – but a lapse in touchscreen hygiene control could have potentially disastrous consequences.4,5,6 Additionally, some evidence suggests that the regular cleaning of touchscreens with bactericidal agents can damage screens.5

Societally, our response to these risks tend to be in proportion to the severity of the infection risk within a given environment: Touchscreens in hotels and train stations may be cleaned on a varying basis – but they may not present a greater risk than, say, a handrail or elevator button. Touchscreens in more controlled environments, for example, restaurants, are riskier and as such are cleaned more regularly. Touchscreens in medical settings are, generally, cleaned thoroughly and very regularly. However, a simpler and more effective solution to the threat posed by touchscreens in these environments would be to supplant the technology with an equally usable solution that does not require physical contact. Developments in simple gesture recognition with low-cost sensors may provide a solution.

Gesture Recognition as an Alternative to Touchscreen Technology


Gesture recognition is an emerging technology that has yet to become commonplace. The goal of gesture recognition research is to produce affordable technologies that can interpret human gestures, thus enabling non-contact interfacing with technology. This offers big advantages for many applications where touchscreens are commonly used – in the previously mentioned examples, implementation of basic gesture recognition as a substitute for touchscreens would eliminate infection hazards and the usage of touchscreens for basic interactions as regular, cheaper, screens could be used instead.

Screen Activation Based on People Presence in Close Proximity 

Equipping devices with gesture recognition technology confers additional advantages: gesture sensors can double as proximity sensors, allowing devices to switch on in response to the presence of a user in front of the device, and switch off when there are no users present. Not only does touchless device activation offer energy savings, but content display can be adapted to respond to presence and movement.

ToF Technology for Inexpensive, GDPR compliant and Simple Gesture-Sensing


A great deal of gesture recognition research focuses on advanced image processing and computer vision techniques to infer gestures using ordinary cameras. However, this work is often highly complex, with many approaches adopting a machine-learning approach and requiring significant computational power to effectively interpret images.7

Time-of-Flight (ToF) technology offers a leaner and less computationally demanding solution to simple gesture recognition. Time-of-Flight sensors work by emitting a beam of invisible infrared light and measuring the amount of time taken for the light to reflect off a target and return to the sensor. By precisely measuring this, the sensor can build up a simple 3D picture of the environment in front of it.

Infrared ToF works effectively at short range and offers the prospect of easily capturing salient gesture information without the need for the kind of computationally demanding processing required for interpretation of conventional 2D or 3D camera images.

Sensor manufacturers Terabee have developed proof-of-concept gesture sensing systems to work in conjunction with their range of low-cost distance sensors, including the TeraRanger Evo Mini8,9. These modular ToF sensors are designed to be as versatile, lightweight and accurate as possible, while still providing an effective gesture-sensing solution at a retail-compatible price point.

Innovation in Gesture Recognition Technology


Unlike some gesture sensing technology, Terabee’s world-leading ToF sensors easily discriminate between noise and real interaction, and are fully functional in low light or complete darkness. All Terabee sensors are designed for maximum compatibility with other technologies, with USB and UART interfaces as standard and almost unlimited possibilities for integration.

With a deep knowledge of sensor technologies and applications, Terabee’s engineers can design custom sensing solutions for any application. Get in touch to order a sample, or to enquire about developing a bespoke contactless gesture-sensing solution.

References and Further Reading

  1. Touchscreens vectors of infectious disease. Available at: (Accessed: 23rd March 2020)
  2. McDonald’s touch screen poo: London microbiologist found bacteria on fast-food chain equipment - The Washington Post. Available at: (Accessed: 23rd March 2020)
  3. Borchgrevink, C., Cha, J. & Kim, S. Hand Washing Practices in a College Town Environment.
  4. Arkoff, H. & Ortega, R. A. Touchscreen technology: Potential source of cross-infections [6]. Anesthesia and Analgesia 75, 1073 (1992).
  5. Cosgrove, M. S. Infection Control in the Operating Room Article in Critical Care Nursing Clinics of North America. (2015). doi:10.1016/j.cnc.2014.10.004
  6. Sattar, S. A. & Maillard, J. Y. The crucial role of wiping in decontamination of high-touch environmental surfaces: Review of current status and directions for the future. Am. J. Infect. Control 41, S97–S104 (2013).
  7. Wu, Y. & Huang, T. S. Vision-based gesture recognition: A review. in Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) 1739, 103–115 (Springer Verlag, 1999).
  8. Custom designed gesture recognition applications. Available at: (Accessed: 23rd March 2020)
  9. TeraRanger Evo Mini - single & multi-pixel capability in 1 sensor - 0.03m to 3.3m range - 9 grams. Available at: (Accessed: 10th March 2020)

This information has been sourced, reviewed and adapted from materials provided by Terabee.

For more information on this source, please visit Terabee.


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