Boundary layer model to account for thick mask effects in photolithography

A direction instructing apparatus includes an image inputting section for inputting data for a two-dimensional image picked up with an image sensor having an image processing function, a projection computing section for computing projections for the two-dimensional image as a whole in directions according to the data inputted into the image inputting section, a movement computing section for computing a one-dimensional movement vector for each projection according to the projection computed in the projection computing section, and a direction estimating section for estimating a two-dimensional movement vector for the two-dimensional image according to the one-dimensional movement vector computed in the movement computing section.