Patent ID: 8224103

Claim:
An image encoding method, which is performed using a processor, for encoding, from a pixel value of a pixel quantized in m-bit accuracy and which is included in a pixel array where a plurality of pixels are arrayed, a pixel value quantized in n-bit accuracy, where n-bit is smaller than m-bit, the image encoding method comprising: determining whether a pixel value of a pixel to be encoded is a specific pixel value; when the pixel value of the pixel to be encoded is the specific pixel value, encoding the pixel value of the pixel to be encoded by allocating a specific quantized representative value included in a range of quantized representative values to the pixel to be encoded, the range of the quantized representative values including a quantized representative value which is quantized in n-bit accuracy from the pixel value of the pixel to be encoded; and when the pixel value of the pixel to be encoded is other than the specific pixel value, adding a predetermined offset value to the pixel value of the pixel to be encoded, and encoding the pixel value of the pixel to be encoded by allocating a quantized representative value other than the specific quantized representative value to the pixel value to be encoded, the range of the quantized representative values including the quantized representative value other than the specific quantized representative value.