1. A method of processing image signals, comprising: determining whether each of multiple units of input pixel data received from an image sensor is bad pixel data generated by a bad pixel of the image sensor or normal pixel data generated by a normal pixel of the image sensor; and performing interpolation to generate image data corresponding to the bad pixel using only normal pixel data and omitting bad pixel data; wherein each unit of the input pixel data is determined as bad pixel data or normal pixel data based on coordinates of bad pixels stored in a non-volatile memory device, and wherein the coordinates of the bad pixel are stored in the non-volatile memory device upon determining that at least one additional bad pixel is located in an area of n×n pixels centered on the bad pixel, where n is an odd number greater than or equal to three.