@INTERACTIONSMAG 78 INTERACTIONS JANUARY–FEBRUARY2019 FORUM INTERACTION TECHNOLOGIES

mobile-based user authentication. Proc. of the 2017 CHI Conference on Human Factors in Computing Systems. ACM, New York, 2017, 3751–3763; https://doi. org/10.1145/3025453.3025461

4. Abdelrahman, Y., Velloso, E., Schmidt, A., Abdelrahman, Y., and Schmidt, A.

Cognitive heat: Exploring the usage of thermal imaging to unobtrusively estimate cognitive load. Proc.of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies 13, 3 (2017), Article 33; https://doi.org/10.1145/3130898

5. Ioannou, S., Gallese, V., and Merla, A.

Thermal infrared imaging in psychophysiology: Potentialities and limits.

Psychophysiology 51, 10 (2014), 951–963; https://doi.org/10.1111/psyp.12243

6. Vala, H.J. and Baxi, A. A review on Otsu image segmentation algorithm.

International Journal of Advanced Research in Computer Engineering & Technology 2, 2

(Feb. 2013).

Yomna Abdelrahman graduated from the German University in Cairo in 2010. She then earned her master’s degree in international computer hardware and software (INFOTECH) at Stuttgart University, Germany. She completed her Ph.D. on thermal imaging and novel interactive systems in the hciLab at the University of Stuttgart. Recently she joined University of Bundeswehr Munich as a post doc. → [e-mail]

Albrecht Schmidt is a computer science professor at the Ludwig-Maximilians-Universität in Munich. He works at the intersection of ubiquitous computing, digital media, and human-computer interaction. His research interests are in creating digital technologies to augment perception and the human mind. He has a Ph.D. from Lancaster University. → [e-mail]

Reductions in price and size come at the cost of resolution and thermal sensitivity. Noncommercial thermal cameras can detect subtle changes in temperature (up to 0.005˚C), but while this ability is reduced in most commercial cameras (up to 0.04˚C), it does not affect their potential utility.

Interestingly, although thermal imaging operates in a different spectrum from RGB, known computer-vision techniques that use existing open source libraries (e.g., OpenCV; https://opencv. org/) work with the images generated from thermal cameras. Additionally, having the temperature information for each pixel enhances existing techniques such as person-detection, as our body temperature can be easily extracted from the background. Applying the typical image-processing techniques shown in Figure 12, different features could be extracted, such as touch points, facial temperature, and vein patterns.

Thermal imaging over the next 10
years. Thermal imaging has witnessed a
vast increase in application as well as
specification, where it has been involved
in HCI research, for instance, in building
novel interactive techniques. We
envision that with the DIY movement,
where sensors are commercially available
and building your own hardware
becomes more common, thermal
imaging will be further deployed in a
variety of use cases, from building
interactive systems based on thermal
imaging to replace current technologies,
to deploying it in educational settings to
monitor cognitive load, to replacing
current authentication techniques.
Furthermore, thermal cameras could be
included in all commercial smartphones,
as a feature as indispensable as current
cameras. This will open up a new field of
research in HCI, namely the implications
and privacy concerns raised by using
cameras that operate in the non-visible
spectrum.

Endnotes

1. Abdelrahman, Y., Sahami Shirazi, A., Henze, N., and Schmidt, A. Investigation of material properties for thermal imaging-based interaction. Proc. of the 33rd Annual ACM Conference on Human Factors in Computing Systems. ACM, New York, 2015, 15–18; https://doi. org/10.1145/2702123.2702290

2. Sahami Shirazi, A., Abdelrahman, Y., Henze, N., Schneegass, S., Khalilbeigi, M., and Schmidt, A. Exploiting thermal reflection for interactive systems. Proc. of the 32nd Annual ACM Conference on Human Factors in Computing Systems. ACM, New York, 2014, 3483–3492; https://doi.org/10.1145/2556288.2557208

3. Abdelrahman, Y., Khamis, M., Schneegass, S., and Alt, F. Stay cool! Understanding thermal attacks on

 

DOI: 10.1145/3297778 © 2019 ACM 1072-5520/19/01 $15.00

Figure 11. Evolution of thermal cameras in terms of size and cost. Source: https://www.flir.de
Figure 10. Facial temperature captured by a
thermal camera.

Figure 12. Thermal-image processing for diverse features extraction [ 6].