A method and a system for using compression sensing to provide low data rate transmission and low computational complexity to determine anomalies in video data obtained by a video camera or other motion detection device. The video data is divided into varying sized video blocks based on an anticipated size of objects of interest within the video, and based on a distance between a video camera and the objects of interest. Features are extracted from the video data of each block to detect anomalies if a feature vector is outside of an “allowed range.” By utilizing varying sized video blocks, anomalies are more effectively and efficiently detected in the video data.