An in-vivo device captures images of the GI system and transfers frames to an external system for analysis. As frames are transferred from the in-vivo device to the external system frames may be classified as belonging to a particular GI section. Based on statistical analysis of the classes, a temporary determination may be made, that the in-vivo device has transitioned to a “target section”, and, as a result of the temporary determination, the operation mode of the in-vivo device may temporarily change from a first mode to a second mode. If the temporary determination is followed by a determination which is based on analysis of additional classes, the determination that the in-vivo device is in the target section may be made final and the in-vivo device may remain in the second mode. Otherwise, the first operation mode may be resumed and the whole transition determination process may start anew.