US Patent 11539922 Point-to-point visual communications in a security monitoring system

A monitoring system includes a doorbell unit that includes a camera and a display and that is configured to receive a request to access the property. The monitoring system includes a monitor control unit that is configured to determine an authentication protocol for determining whether to grant the visitor access to the property. The monitor control unit generates a first image and transmits authentication data to a computing device. The monitor control unit provides the first image and instructions to output the first image on the display of the doorbell unit. The monitor control unit receives a second image captured by the camera of the doorbell unit. The monitor control unit determines whether the second image includes a representation of data that is based on processing the first image in combination with the authentication data. The monitor control unit grants or denies the visitor access to the property.