A display device comprising: a communication interface connected with an external electronic device; a display; a memory; and a processor configured to: display a broadcast image received from the external electronic device on the display; receive a first control signal that is for controlling the external electronic device, wherein in response to the first control signal being received at the external electronic device, the external electronic device is arranged to blend a user interface, UI, image corresponding to the first control signal into the broadcast image; capture the broadcast image displayed on the display; determine a noise level by using a spatial frequency calculated for one or both of each of the row lines of pixels included in the captured broadcast image and each of the column lines of pixels included in the captured broadcast image; determine a region, which has a noise level equal to or less than a specified level, as a user interface, UI, image region, which corresponds to the first control signal, in the broadcast image; and store information relating to the UI image region in the memory, the information including position of the UI image region in the broadcast image; wherein the processor is further configured to: display a substitutional advertisement image on the display received from an advertisement server; and in response to a second control signal, that is for controlling the external electronic device, being received while displaying the substitutional advertisement image, wherein the substitutional advertisement image is displayed based on the stored information relating to the UI image region, stop displaying the substitutional advertisement image. a communication interface connected with an external electronic device; a display; a memory; and a processor configured to: display a broadcast image received from the external electronic device on the display; receive a first control signal that is for controlling the external electronic device, wherein in response to the first control signal being received at the external electronic device, the external electronic device is arranged to blend a user interface, UI, image corresponding to the first control signal into the broadcast image; capture the broadcast image displayed on the display; determine a noise level by using a spatial frequency calculated for one or both of each of the row lines of pixels included in the captured broadcast image and each of the column lines of pixels included in the captured broadcast image; determine a region, which has a noise level equal to or less than a specified level, as a user interface, UI, image region, which corresponds to the first control signal, in the broadcast image; and store information relating to the UI image region in the memory, the information including position of the UI image region in the broadcast image; display a broadcast image received from the external electronic device on the display; receive a first control signal that is for controlling the external electronic device, wherein in response to the first control signal being received at the external electronic device, the external electronic device is arranged to blend a user interface, UI, image corresponding to the first control signal into the broadcast image; capture the broadcast image displayed on the display; determine a noise level by using a spatial frequency calculated for one or both of each of the row lines of pixels included in the captured broadcast image and each of the column lines of pixels included in the captured broadcast image; determine a region, which has a noise level equal to or less than a specified level, as a user interface, UI, image region, which corresponds to the first control signal, in the broadcast image; and store information relating to the UI image region in the memory, the information including position of the UI image region in the broadcast image; wherein the processor is further configured to: display a substitutional advertisement image on the display received from an advertisement server; and in response to a second control signal, that is for controlling the external electronic device, being received while displaying the substitutional advertisement image, wherein the substitutional advertisement image is displayed based on the stored information relating to the UI image region, stop displaying the substitutional advertisement image. display a substitutional advertisement image on the display received from an advertisement server; and in response to a second control signal, that is for controlling the external electronic device, being received while displaying the substitutional advertisement image, wherein the substitutional advertisement image is displayed based on the stored information relating to the UI image region, stop displaying the substitutional advertisement image.