Shadow-based fall detection

A system comprising one or more computers and one or more storage devices on which are stored instructions that are operable, when executed by the one or more computers, to cause the one or more computers to perform operations comprising:

• obtaining, from a camera, an image of a portion of a property;
• determining whether a shadow is likely depicted in the image;
• in response to determining that a shadow is likely depicted in the image, determining whether the shadow in the image likely represents a potentially falling person;
• and
• in response to determining that the shadow in the image likely represents a potentially falling person, performing one or more actions for the potentially falling person.

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:

• obtaining, from a camera, an image of a portion of a property;
• determining whether a first likelihood that a shadow is depicted in the image satisfies a first likelihood threshold;
• in response to determining that the first likelihood that a shadow is depicted in the image satisfies the first likelihood threshold, determining whether a second likelihood that the shadow in the image represents a potentially falling person satisfies a second likelihood threshold;
• and
• in response to determining that the second likelihood that the shadow in the image represents a potentially falling person satisfies the second likelihood threshold, performing one or more actions for the potentially falling person.