1. An indoor-outdoor detection method, the method comprising: constructing a first indoor-outdoor detector; constructing a second indoor-outdoor detector; determining a normalized brightness of a subject image; generating a comparison result based on the determined normalized brightness and a threshold brightness value; selectively applying one of the first detector or the second detector to the subject image and generating a detection result, based on the comparison result; and performing image signal processing on the subject image based on the detection result.