Abstract: The present invention relates to an interpolation technology adapted to a picture motion, in particular to a deinterlacing apparatus which is capable of performing accurate motion detection by finding each BD by using an initial detection value when a BD and a BPPD used for the motion detection are detected and performing low pass filtering in order to remove high frequency noise element, improving picture quality by showing motion alteration degree smoothly, and reducing manufacture cost of a circuit to be implemented by simplifying the circuit.