Apparatus and method for displaying images

A method of displaying images, comprising:

• outputting, by a first image output unit set to master operation mode, an image signal to be displayed;
• if the first image output unit has failed, switching a second image output unit set to slave operation mode to master operation mode, and continuously outputting, by the second image output unit configured to be set to slave operation mode, the image signal or a new image signal;
• comparing, by an image signal selection unit, an IP source address of a master message received from any one of the first image output unit and the second image output unit with previously stored address information;
• selecting, by the image signal selection unit, the image signal that is received from any one of the first image output unit and the second image output unit that has a matching address;
• and
• displaying, by an image display unit, the selected image signal,
• wherein switching the second image output unit to master operation mode and continuously outputting the image signal or the new image signal comprises:
• periodically receiving the master message from the first image output unit;
• transmitting a reception acknowledgement message responsive to the master message to the first image output unit;
• periodically receiving the information about the image signal from the first image output unit, determining whether there is an image file whose name is identical to the name of the image being currently output, and, if there is no stored image file, discarding the received information about the image signal, and, if there is a stored image file, storing the received information about the image signal;
• and
• if the master message or the information about the image signal has not been received from the first image output unit for a time equal to or longer than a predetermined time, determining that the first image output unit has failed, and switching operation mode of the second image output unit to master operation mode.