An image processing apparatus comprising: a determining unit configured to: calculate a pixel value difference between a first pixel of a first image and a second pixel of a second image (211; 212; 213), wherein the first image and the second image (211; 212; 213) are a plurality of input frame images used to compute a hologram pattern, and the first pixel and the second pixel have a same coordinate value; determine at least one pixel having a pixel value difference between the first image and the second image (211; 212; 213) lower than a critical value, said pixel value including at least one of an intensity value and a depth value; and generate a mask for the second image (211; 212; 213) to distinguish each of the determined at least one pixel from at least one other pixel having a pixel value difference equal or higher than said critical value; and a computing unit configured to: compute a hologram pattern for all pixels of the first image; generate, based on the mask, a background hologram for the first image (211; 212; 213) in an area having the pixel value difference between the first image and the second image lower than the critical value; compute, based on the mask, a foreground hologram (231; 232; 233) for the second image in an area having the pixel value difference greater than or equal to the critical value; and synthesize the background hologram and the foreground hologram (231; 232; 233) to generate a hologram pattern (241; 242; 243) of the second image (211; 212; 213). a determining unit configured to: calculate a pixel value difference between a first pixel of a first image and a second pixel of a second image (211; 212; 213), wherein the first image and the second image (211; 212; 213) are a plurality of input frame images used to compute a hologram pattern, and the first pixel and the second pixel have a same coordinate value; determine at least one pixel having a pixel value difference between the first image and the second image (211; 212; 213) lower than a critical value, said pixel value including at least one of an intensity value and a depth value; and generate a mask for the second image (211; 212; 213) to distinguish each of the determined at least one pixel from at least one other pixel having a pixel value difference equal or higher than said critical value; and calculate a pixel value difference between a first pixel of a first image and a second pixel of a second image (211; 212; 213), wherein the first image and the second image (211; 212; 213) are a plurality of input frame images used to compute a hologram pattern, and the first pixel and the second pixel have a same coordinate value; determine at least one pixel having a pixel value difference between the first image and the second image (211; 212; 213) lower than a critical value, said pixel value including at least one of an intensity value and a depth value; and generate a mask for the second image (211; 212; 213) to distinguish each of the determined at least one pixel from at least one other pixel having a pixel value difference equal or higher than said critical value; and a computing unit configured to: compute a hologram pattern for all pixels of the first image; generate, based on the mask, a background hologram for the first image (211; 212; 213) in an area having the pixel value difference between the first image and the second image lower than the critical value; compute, based on the mask, a foreground hologram (231; 232; 233) for the second image in an area having the pixel value difference greater than or equal to the critical value; and synthesize the background hologram and the foreground hologram (231; 232; 233) to generate a hologram pattern (241; 242; 243) of the second image (211; 212; 213). compute a hologram pattern for all pixels of the first image; generate, based on the mask, a background hologram for the first image (211; 212; 213) in an area having the pixel value difference between the first image and the second image lower than the critical value; compute, based on the mask, a foreground hologram (231; 232; 233) for the second image in an area having the pixel value difference greater than or equal to the critical value; and synthesize the background hologram and the foreground hologram (231; 232; 233) to generate a hologram pattern (241; 242; 243) of the second image (211; 212; 213).