1. A method of calculating sharpness of an image using image processing circuitry, the method comprising: using the image processing circuitry, calculating a first sharpness value by applying a first filter to pixels in the image; using the image processing circuitry, calculating a second sharpness value by applying a second filter to the pixels; and using the image processing circuitry, calculating a third sharpness value based on a ratio of the first and second sharpness values.