An image processing method includes adjusting a brightness of each of a first image and a second image based on a first exposure time when the first image is captured and a second exposure time when the second image is captured, respectively, the first and second images being generated by capturing a same object under different light conditions, estimating an intensity of light, reaching the object when the second image is captured, based on the adjusted brightness of each of the first and second images, separating the second image into two or more regions according to the estimated intensity of light, determining a target brightness that a final result image is to have, adjusting the brightness of the second image, by different amounts for each of the separated regions, based on the target brightness and generate the final result image based on the adjusted brightness of the second image.