Fig. 7: Design of the exploration strategy.

a The blob detection technique’s accuracy reduces as the distance between the IR camera and the target increases. 4.2 m (*) could be selected as the maximum distance for acceptable accuracy. This distance’s corresponding thermal information (28 °C to 38 °C) is 0.8%. Data are shown as mean. b IR images and their detected blobs (i.e., red dots) at different distances. The square boxes indicating the image’s hottest region are used to evaluate the blobs’ accuracy. c Flowchart of the exploration strategy for both indoor and outdoor applications. The Indoor Exploration Strategy utilizes the thermal information from the IR image within a specific range to facilitate the transition between three distinct phases. An Outdoor Extension Adjustment module enhances this strategy for outdoor environments by analyzing pixels in a human range near the thermal blob’s center. Besides, If a heat source is detected but then lost when the hybrid system has moved out of the camera’s field of view, the algorithm will navigate the hybrid system and turn back to reattempt capturing the heat source. The algorithm reverts to Phase I: Stochastic Exploration when it continuously fails to find the heat source, forcing a repeated search for thermal sources in outdoor areas.