Psychophysical Experimental Setup for Active Observers


Most past and present research in computer vision involves passively observed data. Humans, however, are active observers outside the lab; they explore, search, select what and how to look.

PESAO is designed for investigating active, visual observation in a 3D world. The goal was to build an experimental setup for various active perception tasks with human subjects (active observers) in mind that is capable of tracking the head and gaze.

While many studies explore human performances, usually, they use line drawings portrayed in 2D, and no active observer is involved. PESAO allows us to bring many studies to the three-dimensional world, even involving active observers. In our instantiation, it spans an area of 400cm x 300cm and can track active observers at a frequency of 120Hz.

Furthermore, PESAO provides tracking and recording of 6D head motion, gaze, eye movement-type, first-person video, head-mounted IMU sensor, birds-eye video, and experimenter notes. All are synchronized at microsecond resolution.

Example gaze recording.

Viewing Frusta

A sketch of PESAO.


PESAO Tech-Report (
A detailed, technical report of PESAO. Describing functionalities, hardware and software (PESAOlib).

PESAOlib (JTL GitLab)
The GitLab repository of PESAOlib. The software behind PESAO.

Viewing Frusta

Two example recordings of PESAO. Head pose trajectory with fixations.

How to cite

In case you use this work in one of your publications, please make sure to cite us:

Markus D. Solbach and John K. Tsotsos.
"PESAO: Psychophysical Experimental Setup for Active Observers"
arXiv preprint arXiv:2009.09933 (2020).
Viewing Frusta

A heatmap visualization of fixations using PESAO.


  • We provide no guarantees for system performance.
  • The system is provided as-is.
  • Developed for research purposes only, and commercial use is not permitted.
  • For comments, problems and questions, please send us an email to solbach(at)eecs(dot)yorku(dot)ca (replies are not guaranteed).
  • No level of technical support can be provided.
  • If you use any aspect of this system, we respectfully request that all relevant publications that result from any use of this paper or system cite this paper.

A subject performing an experiment with PESAO.