A method of image sampling and an apparatus thereof. The apparatus comprises: an adder; a first register, the output of which is fed back to the adder; a first multiplexer, which outputs a ratio or a weighted parameter; a multiplier, which receives an input image value and the output of the first multiplexer; an adder/subtracter, which receives the output of the multiplier; a second multiplexer, which receives the output of the adder/subtracter and the multiplier; and a second register, which receives the output of the second multiplexer. By the method of approximation and recursion, the input image data can be processed in real time to produce the output image data.