1. An image processing apparatus comprising: a small area divider that divides, on the basis of edge information of an image, the image into multiple small areas each including multiple pixels; an attribute probability estimator that estimates attribute probability for each of the small areas, which is probability that the small area is attributed to a specific area to be detected; an adjacent-small-area connection strength calculator that calculates connection strength that quantitatively indicates a degree to which small areas adjacent to each other among the multiple small areas are attributed to the same area that is the specific area or a non-specific area other than the specific area; and a specific area detector that detects the specific area by dividing the image into the specific area and the non-specific area on the basis of the attribute probability and the connection strength.