1. An image processing apparatus comprising: an area dividing unit that divides an image obtained by capturing inside of a body lumen into one or more areas by using a value of a specific wavelength component that is specified in accordance with a degree of absorption or scattering in vivo from a plurality of wavelength components included in the image or from a plurality of wavelength components obtained by conversion of the plurality of wavelength components; a unit that sets a discriminant criterion for each of the one or more areas, each discriminant criterion is independent of the other discriminant criterion; and a target-of-interest site specifying unit that specifies a target-of-interest site in the one or more areas by using the discriminant criterion in accordance with each of the one or more areas obtained by the division by the area dividing unit.