1. An imaging apparatus comprising: an imaging section configured to acquire a plurality of images that are consecutively taken in time series by an imaging device; an evaluation value acquiring section configured to employ one of the images acquired by the imaging section as a reference image and divide the reference image into a plurality of blocks, and to acquire evaluation values indicating amounts of high-frequency components for the blocks, respectively; a reference region setting section configured to set a region as a reference region, the region comprising blocks selected from among the plurality of blocks based on the evaluation value for each block acquired by the evaluation value acquiring section; a motion vector acquiring section configured to acquire a motion vector for each of the selected blocks of the reference region of the reference image set by the reference region setting section; and an image processing section configured to combine images including the reference image and another image by positioning the images so as to overlap subject portions in each image based on the motion vectors acquired by the motion vector acquiring section.