Face recognition image data cache

A non-transitory computer readable storage medium storing instructions executable by a data processing apparatus and upon such execution cause the data processing apparatus to perform operations comprising:

• receiving an image from a first camera that is in communication with the data processing apparatus, wherein the data processing apparatus is for the first camera and in communication with a first cache for the first camera that is configured to maintain, for a first group of multiple different people, image data for each person in the first group, each person in the first group having at least a threshold likelihood of being within a field of view of the first camera;
• detecting, in the image, a face of a person;
• in response to detecting the face of the person, determining, using data for the image, whether the first cache includes data for the person by searching the first cache;
• determining that the first cache does not include data for the person;
• in response to determining that the first cache does not include data for the person, sending, to a second data processing apparatus in communication with a second camera that is a different camera than the first camera, a request for data that indicates whether a second cache for the second camera includes data for the person,
• wherein the second cache for the second camera a) is a separate cache from the first cache, b) is configured to maintain, for a second group of multiple different people, image data for each person in the second group, each person in the second group having at least a threshold likelihood of being within a field of view of the second camera, and c) is in communication with the second data processing apparatus;
• in response to sending the request for data indicating whether the second cache for the second camera includes data for the person, receiving, from the second data processing apparatus when the second data processing apparatus determines that the second cache for the second camera includes the data for the person, a message that includes data for the person;
• and
• in response to receiving the message that includes data for the person, storing at least some of the data for the person in a first cache for the first camera that is a different cache than the second cache for the second camera.

A computer-implemented method comprising:

• receiving, by a system, an image from a first camera that is in communication with the system, wherein the system is for the first camera and in communication with a first cache for the first camera that is configured to maintain, for a first group of multiple different people, image data for each person in the first group, each person in the first group having at least a threshold likelihood of being within a field of view of the first camera;
• detecting, in the image, a face of a person;
• in response to detecting the face of the person, determining, using data for the image, whether the first cache includes data for the person by searching the first cache;
• determining that the first cache does not include data for the person;
• in response to determining that the first cache does not include data for the person, sending, to a second system in communication with a second camera that is a different camera than the first camera, a request for data that indicates whether a second cache for the second camera includes data for the person,
• wherein the second cache for the second camera a) is a separate cache from the first cache, b) is configured to maintain, for a second group of multiple different people, image data for each person in the second group, each person in the second group having at least a threshold likelihood of being within a field of view of the second camera, and c) is in communication with the second system;
• in response to sending the request for data indicating whether the second cache for the second camera includes data for the person, receiving, from the second system when the second system determines that the second cache for the second camera includes the data for the person, a message that includes data for the person;
• and
• in response to receiving the message that includes data for the person, storing at least some of the data for the person in a first cache for the first camera that is a different cache than the second cache for the second camera.