Device and method of estimating image signal noise and apparatus and method of converting image signal using the same

An apparatus for converting an image signal, the apparatus comprising:

• a noise estimation device which determines a noise level by using a minimum frame sum of absolute difference (SAD) detected from a plurality of input image fields;
• an interpolation filter which interpolates the plurality of input image fields;
• and
• an interpolation filter control unit which generates a filter coefficient control signal of the interpolation filter by using the noise level determined by the noise estimation device.

A method of estimating noise of an image signal, the method comprising:

• calculating a plurality of frame sum of absolute differences (SADs) by using a plurality of image fields;
• determining a minimum frame SAD among the plurality of frame SADs;
• and
• determining the noise level by using the minimum frame SAD.

A computer-readable recording medium having embodied thereon a computer program for executing a method comprising:

• calculating a plurality of frame sum of absolute differences (SADs) by using a plurality of image fields;
• determining a minimum frame SAD among the plurality of frame SADs;
• and
• determining the noise level by using the minimum frame SAD.