Image Processing Method

An image processing method for removing a noise component contained in an original image, comprising:

• adaptively smoothing a noise component contained in an original image by distinguishing the noise component from an edge component present within a smoothing target area through comparison of a noise fluctuation index value and a spatial fluctuation width over which original image signals fluctuate;
• extracting a temporary noise component based upon a differential signal representing a difference between the original image and an image resulting from adaptive smoothing;
• statistically re-examining a distribution of the temporary noise component having been extracted by comparing the extracted temporary noise component with the noise fluctuation index value again;
• extracting an actual noise component by further excluding a component less likely to be a noise component from the extracted temporary noise component based upon examination results;
• and
• removing noise from the original image based upon the actual noise component having been extracted.

An image processing method for removing a noise component contained in an original image, comprising:

• smoothing an original image by using a specific noise model having a distribution function;
• extracting a temporary noise component based upon a differential signal representing a difference between the original image and the image having been smoothed;
• estimating a quantity of false noise component present in the temporary noise component having been extracted by comparing a value indicated for the temporary noise component with the distribution function of the specific noise model;
• extracting an actual noise component by excluding the false noise component in the estimated quantity from the temporary noise component;
• and
• removing noise from the original image based upon the actual noise component having been extracted.

An image processing method for removing a noise component contained in an original image, comprising:

• generating a plurality of band-limited images assuming gradually lowered resolution levels by filtering the original image;
• extracting a noise component free of a non-noise component in each band-limited image by executing noise removal processing by comparing the band-limited image with a noise fluctuation index value determined in correspondence to the band-limited image;
• synthesizing noise component signals having been extracted from the band-limited images to generate a noise component assuming a resolution level matching the resolution level of the original image;
• estimating a quantity of a false noise component present in the synthesized noise component by comparing a level of the synthesized noise component with the noise fluctuation index value determined in correspondence to the original image again;
• extracting an actual noise component by excluding the false noise component from the synthesized noise component based upon estimation results;
• and
• removing noise from the original image based upon the actual noise component having been extracted.