*2.6. Details of Experiments*

The algorithm parameters have been set to:


Common parameters for all algorithms were: the bandpass filter of order = 128 and bandwidth = (35–180) bpm (which is equivalent to 0.583–3.00 Hz), the HR postprocessing buffer length M was equivalent to 1 s.

Several video sequences of participants performing HCI tasks were recorded using lossless compression (Huffman codec) and 24-bits-per-pixel format (RGB stream), image resolution of 640 × 480 pixels and frame rate of 60 FPS. Each sequence was approximately 5 min long. The RealSense camera was positioned in such a way that the face of the monitored participant was in the frontal position. All participants were asked to perform various tasks reflecting typical user-computer interaction scenarios. Thus, each video sequence consists of the following parts:


Only selected parts (1, 2, 4 and 6) were included in the study. The video sequences were recorded in different places and under different conditions (illumination, distance, and if possible similar camera parameters). A description of these videos is provided in Table 2. Examples of video frames are shown in Figure 5. Duration, average illumination values and standard deviation of accelerations for sequences are given in Tables A1 and A2 (Appendix A).

**Figure 5.** An example of video frames: (**a**) video No.5; (**b**) video No.9.


#### **Table 2.** Recorded video sequences covered by the study.

#### **3. Result**
