A mobile device configured to match image qualities among a plurality of display devices (101, 102), the mobile device comprising: an image acquirer comprising a camera configured to capture an image of a first displayed image being displayed on a first display device as a first acquired image and an image of a second displayed image being displayed on a second display device as a second acquired image, wherein said first and second displayed images are the same image; characterised in that the mobile device further comprises: a controller configured to: acquire pixel values (701 to 715) from each of the first acquired image and the second acquired image, wherein the respective pixel values are acquired by respectively dividing the first acquired image and the second acquired image into equal parts at predetermined intervals in horizontal and vertical directions and acquiring said pixel values at the positions at which the equal parts cross each other; compare the first acquired image and the second acquired image with each other by calculating a difference in an image quality between the first acquired image and the second acquired image, wherein the image quality is obtained for each of said first acquired image and said second acquired image by calculating an average, median or mode of the color values, brightness or luminance of the respective acquired pixel values; and determine a respective image quality correction value for the first display device and the second display device, wherein the image quality correction values depend on said difference and are equal in absolute value and opposite in sign; and wherein the mobile device further comprises a communicator configured to transmit the respective image quality correction values to the first display device and the second display device. an image acquirer comprising a camera configured to capture an image of a first displayed image being displayed on a first display device as a first acquired image and an image of a second displayed image being displayed on a second display device as a second acquired image, wherein said first and second displayed images are the same image; characterised in that the mobile device further comprises: a controller configured to: acquire pixel values (701 to 715) from each of the first acquired image and the second acquired image, wherein the respective pixel values are acquired by respectively dividing the first acquired image and the second acquired image into equal parts at predetermined intervals in horizontal and vertical directions and acquiring said pixel values at the positions at which the equal parts cross each other; compare the first acquired image and the second acquired image with each other by calculating a difference in an image quality between the first acquired image and the second acquired image, wherein the image quality is obtained for each of said first acquired image and said second acquired image by calculating an average, median or mode of the color values, brightness or luminance of the respective acquired pixel values; and determine a respective image quality correction value for the first display device and the second display device, wherein the image quality correction values depend on said difference and are equal in absolute value and opposite in sign; and wherein the mobile device further comprises a communicator configured to transmit the respective image quality correction values to the first display device and the second display device. acquire pixel values (701 to 715) from each of the first acquired image and the second acquired image, wherein the respective pixel values are acquired by respectively dividing the first acquired image and the second acquired image into equal parts at predetermined intervals in horizontal and vertical directions and acquiring said pixel values at the positions at which the equal parts cross each other; compare the first acquired image and the second acquired image with each other by calculating a difference in an image quality between the first acquired image and the second acquired image, wherein the image quality is obtained for each of said first acquired image and said second acquired image by calculating an average, median or mode of the color values, brightness or luminance of the respective acquired pixel values; and determine a respective image quality correction value for the first display device and the second display device, wherein the image quality correction values depend on said difference and are equal in absolute value and opposite in sign; and wherein the mobile device further comprises a communicator configured to transmit the respective image quality correction values to the first display device and the second display device.