Electronic device and method of determining descriptor thereof

An electronic device and a method of determining brightness gradients of an electronic device are provided. The electronic device includes a memory configured to store a digital image, and a processor configured to process the digital image, wherein the processor is configured to recognize at least one object of the digital image, to determine a descriptor used to recognize the object, to determine the descriptor by using at least one of a location, a direction, and a scale of a feature point on the digital image, to determine brightness gradients of pixels located within an area surrounding the feature point, and to determine the brightness gradients of the pixels based on two or more non-orthogonal fixed directions.