A signal processing apparatus of one embodiment of the disclosure includes a composition unit that generates first composite imaging data, by adding together a low-frequency component of first imaging data, a high-frequency component of the first imaging data, and a high-frequency component of second imaging data. The first imaging data is imaging data of a relatively wide angle of view, out of two pieces of imaging data that differ in angle of view from each other. The second imaging data is imaging data of a relatively narrow angle of view, out of the two pieces of the imaging data.