Provided is an image sensor. The image sensor includes a pixel array including pixels arranged along a first direction and a second direction, and partitioned into blocks, a converter configured to convert image signals outputted from the pixels into digital signals based on an image, and an image signal processor configured to add amplitudes of the digital signals belonging to each of the blocks to determine edge blocks among the blocks, compare the amplitudes of the digital signals to determine directions in which direction lines of the edge blocks are directed, and connect the direction lines to extract an edge of the image.