Abstract: A method for low complexity change detection in a sequence of images using configurable block sizes is disclosed. In one embodiment, a first change detection map is generated by performing change detection based on configurable block sizes between a current image and one of an estimated first background image and a previous image. The first change detection map classifies each block as changed or unchanged. The selection between the previous image and the estimated background image for use in change detection is done using a confidence estimate, which is updated both at the low level and at the end of a high-level change analysis. In another embodiment, an estimated second background image is used in addition to the estimate first background image to help quickly adapt when a stationary object starts moving or when a scene object becomes stationary.