Hearing device, accessory device, and a method of operating a hearing system comprising a hearing device and an accessory device is disclosed, the method comprising obtaining, in the accessory device, an audio input signal representative of audio from one or more audio sources; obtaining image data with a camera of the accessory device; identifying one or more audio sources including a first audio source based on the image data; determining a first model comprising first model coefficients, wherein the first model is based on image data of the first audio source and the audio input signal; and transmitting a hearing device signal to the hearing device, wherein the hearing device signal is based on the first model.