1. An apparatus, comprising: at least one image sensor; a controller, wherein at least one of the controller, or an external controller electronically connected to the controller are operative to: obtain a plurality of images from the image sensor; determine a color difference image of a color difference between consecutive images; determine areas of the color difference image wherein the color difference is greater than a threshold; calculate a total change area as an aggregate area of the determined areas; create a list of occupancy candidates based on filtering of the determined areas if the total change area is less than a light change threshold, wherein each occupancy candidate is represented by a connected component; track the one or more occupancy candidates over a period of time; and detect occupancy if one or more of the occupancy candidates is detected to have moved more than a movement threshold over the period of time.