1. An image processing apparatus for detecting a sky region based on a color image and a depth image, the image processing apparatus comprising: a processor and/or circuitry configured to function as: a first generator configured to generate a first provisional sky map based on pixel values of the color image; a second generator configured to generate a second provisional sky map based on the depth values of the depth image; and an integrator configured to generate a sky map by integrating the first provisional sky map and the second provisional sky map.