APPARATUS FOR RECOGNITION OF DRAWN SHAPES OR VIEW TYPES FOR AUTOMATIC DRAWING INPUT IN CAD SYSTEM

An apparatus for recognition of shapes in drawings for automatic drawing input in a CAD system including a centerline extraction unit for extracting centerlines drawn in center positions of shapes from the line segments discriminated by a line segment discrimination unit, a symmetry determination unit for determining symmetry of shapes based on intersections between the extracted centerlines and straight lines between end points of contour lines, distances between the endpoints of contour lines and the intersections, angles between the centerlines and the straight lines between endpoints of contour lines, and a shape recognition unit for recognizing, using the result of determination of the symmetry determination unit, a shape, a length of line segment, and a position of line segment not indicated by deriving the shape, the length of line segment, and the position of line segment from a shape, a length of line segment, and a position of line segment indicated, and characters recognized by a character recognition unit. In connection with this shape recognition apparatus, an apparatus is provided for recognition of views in drawings for automatic drawing input. Also, shape recognition apparatuses are provided for setting dimensional values known in other views or derived dimension values calculated on the basis of known dimensional values to contour lines, and for adding line segments by producing a line segment based on a matching check.