Image mixing apparatus and pixel mixer

An image mixing apparatus operable to mix on a display screen a plurality of images each of which has a different width of pixels relative to the display screen, said image mixing apparatus comprising:

• a plurality of pixel output units operable to output pixel data items each of which includes color information and a depth value of the corresponding image at output rates which are set respectively for said pixel output units;
• and
• a pixel mixer operable to receive the pixel data items as output from said plurality of pixel output units, and output the color information of the pixel data item whose the depth value indicates, among the depth values of the pixel data items, that the pixel corresponding thereto is located in a foreground position among the pixels corresponding to the pixel data items,
• wherein the depth value is a value indicative of the depth position of the pixel of the corresponding image,
• wherein the color information is information indicative of a color of the pixel forming the corresponding image, and
• wherein at least one of said pixel output units is provided with a storage unit which is used to set the output rate and can be rewritten by an external device.

A pixel mixer operable to mix a plurality of images each of which consists of a plurality of pixels, at least two of the plurality of images having different pixel resolutions, each of the pixels being represented by a pixel value and a depth value, said pixel mixer comprising:

• a pixel selection determination unit operable to successively and concurrently receive the depth values of the pixels of the plurality of images, at the rate of receiving pixels corresponding to the pixel resolution of each image whereby the rates of receiving depth values of at least two images are different, compare the depth values of the pixels, that are currently and simultaneously received, for determining which of the currently received pixels is located in the most foreground position every time at least one depth value changes, and output a select signal indicative of the currently received pixel as determined to be located in the most foreground position;
• and
• a selector unit connected to said pixel selection determination unit, operable to successively and concurrently receive the pixel values of the pixels of the plurality of images together with the select signal in synchronization with the reception of the depth values by said pixel selection determination unit, select one of the pixel values, that are currently and simultaneously received, on the basis of the select signal, and output the pixel value as selected.