An image input apparatus receives image data from a scanner having a
reading surface on which an original image is placed, the image data being
generated through reading the reading surface. An image outline
determination apparatus determines an outline of an original image placed
on the reading surface of the scanner in accordance with the image data
obtained by the scanner. An area designation section designates a
rectangular proposed area of which at least portion enters into an area of
the original image placed on the reading surface. An outline determination
section determines the outline of the original image by repeating a
plurality of number of times an area alteration processing in which a
movement of sides defining an outline of the proposed area outside or
inside the proposed area is determined in accordance with differential or
difference of image data for vicinity of the sides, and the proposed area
is altered in accordance with a decision of the movement, wherein the area
alteration processing is repeated taking an area after the proposed area
is altered as a new proposed area.
