Embodiments of the present disclosure provide a maximum connected domain marking method, a target tracking method and an AR (Augmented Reality)/VR (Virtual Reality) apparatus, and relate to the field of image processing technology, and can obtain the maximum connected domain. A maximum connected domain marking method comprises: marking connected domains of pixels of a binary image and recording equivalent relationships; merging the equivalent connected domains according to the equivalent relationships, for pixels with the equivalent relationships in the marked results; counting the number of pixels in each merged connected domain; determining a connected domain label for the maximum connected domain according to the counted number of pixels in each connected domain; and determining coordinates of boundary pixels in the maximum connected domain based on the connected domain label.
Maximum connected domain marking method, target tracking method, and augmented reality/virtual reality apparatus