Camera detection of object movement with co-occurrence

A computer-implemented method comprising:

• maintaining, in memory and for use with a plurality of sets of images including a first set of images and for each of a plurality of different predetermined movement types for a corresponding object type, optical flow grid criteria, the plurality of different predetermined movement types comprising a predetermined type of movement for a type of an object;
• determining optical flow in pixel groups of the first set of images that are captured by a camera, wherein the first set of images comprises at least one image that depicts an object within a threshold distance of a property;
• determining whether particular pixel groups of the first set of images satisfy the optical flow grid criteria that i) indicate flow motion characteristics of the predetermined type of movement for the type of the object and ii) include criteria for at least one of optical flow magnitude or optical flow direction of the pixel groups of the first set of images, each of the particular pixel groups having the same location in each image of the first set of images;
• in response to determining that the particular pixel groups of the first set of images satisfy the optical flow grid criteria, classifying the particular pixel groups of the first set of images as indicative of the predetermined type of movement for the type of the object;
• receiving a second set of images captured by the camera after the first set of images;
• analyzing second pixel groups of the second set of images that correspond to the locations of the particular pixel groups of the first set of images classified as indicative of the predetermined type of movement for the type of the object;
• determining that the second set of images likely shows the predetermined type of movement for the type of the object using a result of analyzing of the second pixel groups of the second set of images that correspond to the locations of the particular pixel groups of the first set of images classified as indicative of the predetermined type of movement;
• and
• performing one or more actions for the property in response to classifying the particular pixel groups of the first set of images as indicative of the predetermined type of movement for the type of the object and determining that the second set of images likely shows the predetermined type of movement for the type of the object.

One or more non-transitory computer storage media encoded with instructions that, when executed by one or more computers, cause the one or more computers to perform operations comprising:

• maintaining, in memory and for use with a plurality of sets of images including a first set of images and for each of a plurality of different predetermined movement types for a corresponding object type, optical flow grid criteria, the plurality of different predetermined movement types comprising a predetermined type of movement for a type of an object;
• determining optical flow in pixel groups of the first set of images (i) that are captured by a camera and (ii) at least one of which depicts an object within a threshold distance of a property;
• determining whether particular pixel groups of the first set of images satisfy the optical flow grid criteria that i) indicate flow motion characteristics of the predetermined type of movement for the type of the object and ii) include criteria for at least one of optical flow magnitude or optical flow direction of the pixel groups of the first set of images, each of the particular pixel groups having the same location in each image of the first set of images;
• in response to determining that the particular pixel groups of the first set of images satisfy the optical flow grid criteria, classifying the particular pixel groups of the first set of images as indicative of the predetermined type of movement for the type of the object;
• receiving a second set of images captured by the camera after the first set of images;
• analyzing second pixel groups of the second set of images that correspond to the locations of the particular pixel groups of the first set of images classified as indicative of the predetermined type of movement for the type of the object;
• determining that the second set of images likely shows the predetermined type of movement for the type of the object using a result of analyzing of the second pixel groups of the second set of images that correspond to the locations of the particular pixel groups of the first set of images classified as indicative of the predetermined type of movement;
• and
• performing one or more actions for the property in response to classifying the particular pixel groups of the first set of images as indicative of the predetermined type of movement for the type of the object and determining that the second set of images likely shows the predetermined type of movement for the type of the object.