1. A method of encoding an image using exponential Golomb coding, the method comprising: performing entropy coding on an input image by exponential Golomb binarization using a plurality of predetermined thresholds; measuring a bit rate of each of a plurality of bit streams which are generated by performing the entropy coding using each of the plurality of predetermined thresholds; and determining an optimal threshold for exponential Golomb binarization by comparing the bit rates of the plurality of bit streams generated with regard to the plurality of predetermined thresholds wherein thresholds with regard to data of at least one of formats including luma, chroma, an intra mode, and an inter mode which are respectively adaptive to data may be determined based on the corresponding data format.