Reduction of false detections in a property monitoring system using ultrasound emitter

Methods, systems, and apparatus, including computer programs encoded on computer storage media, for reduction of false detections using an ultrasound emitter. One of the methods includes obtaining sensor data captured by a sensor of a property monitoring system; detecting an object represented by the sensor data; determining that the object represented by the sensor data is likely a non-object of interest and being detected as an object of interest; and in response to determining that the object represented by the sensor data is likely the non-object of interest and being detected as the object of interest, sending, to an ultrasound emitter, a command to cause the ultrasound emitter to emit ultrasonic sound around the sensor.