A method of interpolating a signal output from an image sensor including a pixel array having an M×N matrix as a basic pixel block where M and N are integers is provided. The method includes selecting a target pixel signal from among pixel signals output from the basic pixel block; and converting a pattern of a pixel signal output from the pixel array into a Bayer pattern by converting a pixel signal output from the basic pixel block into the Bayer pattern through an operation on the target pixel signal and a neighboring pixel signal of the target pixel signal and interpolating an output signal converted into the Bayer pattern.