Apparatus and method of reducing noise

PURPOSE: A noise reduction apparatus and method thereof are provided to apply a sigma filter of a different size for each section by considering the brightness and direction of an image. CONSTITUTION: A low pass filter module(120) performs a low pass filtering effect for a pixel. A filter selection module(130) selects a filter of flexible size which is applied to a mask area. A sigma filter module(140) performs a sigma filtering for the mask area using the selected filter. A standardizing module(150) standardizes the filtered image.