Monitoring presence or absence of an object using local region matching

Abstract

Methods and systems, including computer-readable media, are described for monitoring presence or absence of an object at a property using local region matching. A system generates images while monitoring an area of the property and, based on the images, detects an object in a region of interest in the area. For each of the images: the system iteratively computes interest points for the object using photometric augmentation applied to the image before each iteration of computing the interest points. A digital representation of the region and the object is generated based on interest points that repeat across the images after each application of the photometric augmentation. Based on the digital representation, a set of anchor points are determined from the interest points that repeat across images. Using the set of anchor points, the system detects an absence or a continued presence of the object in the area of the property.