Patent ID: 8072631

Claim:
An image transmission apparatus comprising: a first communication unit configured to perform first communication with a display apparatus; a detector configured to detect whether the first communication is executable or not; a second communication unit configured to perform second communication by a communication speed lower than that of the first communication with the display apparatus; an image generation unit configured to generate images to be displayed on the display apparatus; a first image control unit configured to transmit the images generated by the image generation unit to the display apparatus via the first communication unit when the first communication is executable; a second image control unit configured to transmit compressed images obtained by compressing the images generated by the image generation unit to the display apparatus via the second communication unit when the first communication is not executable; and an information transmission unit configured to transmit compression utilization information required to display the compressed images on the display apparatus to the display apparatus via the second communication unit, when the first communication is being executed, wherein the information transmission unit first transmits a whole image of one frame as the compression utilization information when the first communication is being executed and then, if any change is made in the whole image, further transmits an image of an area in the whole image where the change has been made, and the second image control unit transmits, after the first communication becomes not executable, an image of an area where change has been made in the whole image, as the compressed image.