An electronic device is disclosed. The disclosed electronic device comprises: a camera module; one or more processors electrically connected to the camera module; and a memory electrically connected to the processors, wherein, when the electronic device operates, the memory can store instructions for making the processors generate an image by using the camera module, calculate angles formed by a virtual horizontal line and a plurality of straight lines included in the image, and select two straight lines on the basis of the calculated angles. Additional various examples are possible.