An electronic device includes a frequency analyzing circuit and a color difference calculating circuit. The frequency analyzing circuit receives an image signal including information about a subject, may convert the image signal into first color data which are based on a first color domain, converts the first color data into frequency data which are based on a frequency domain, and applies frequency weights corresponding to the frequency data to the first color data to generate processed color data. The color difference calculating circuit calculates color difference values for evaluating a color stain generated by the image signal, based on the processed color data. The frequency weights are selected based on sensitivity information of an observer according to a frequency change of the frequency data.