1. An image processing apparatus for processing image data of an original image by compressing a dynamic range of said original image, comprising: a blurred image generating unit that has at least two edge preserving smoothing filters having different characteristics and which processes the image data of said original image by continuous filtering with said at least two edge preserving smoothing filters to generate blurred image data which represents a blurred image of said original image; and a processing unit that processes the image data of said original image by compressing said dynamic range of said original image based on said blurred image data.