Patent ID: 8606028

Claim:
An image encoding apparatus comprising: a pixel bit depth converter to convert a bit depth of each pixel of an input image formed of a plurality of pixels each having an N bit depth to an (N+M) bit depth larger than the N bit depth by M bits; a prediction image generator to generate a prediction image of the (N+M) bit depth with respect to the input image of the (N+M) bit depth from a reference image of the (N+M) bit depth; a subtracter to obtain a differential signal between the input image of the (N+M) bit depth and the prediction image of the (N+M) bit depth; an encoder to encode the differential signal and output encoded image information of the (N+M) bit depth; a decoder to output a decoded difference picture based on the encoded image information; an adder to add the prediction image of the (N+M) depth to the decoded difference picture and output a decoded image of the (N+M) bit depth; a bit depth converter to convert the decoded image of the (N+M) bit depth to (N+M−L) bit depth; and a reference image storing memory to store the converted decoded image as a reference image having the (N+M−L) bit depth (L is an integer).