Image processing using hybrid lookup table

An image processing method and an image processing apparatus converts a binary image into a grayscale image by increasing the size and information quantity of the binary image. The image processing method includes generating a plurality of lookup tables having multiple gray level values assigned to a predetermined pattern of the binary image such that the gray level is retrieved from the plurality of lookup tables depending on the context of the block being processed. The binary image may be converted into the grayscale image by applying the gray value of one of the plurality of lookup tables that corresponds to the context, such as the frequency components of the binary image. With this configuration, since the size and information quantity of an image can be reduced for transmission, it is possible to prevent deterioration of image quality when the image is restored, while also printing at a higher speed.