Image coding method for coding characters using a modified Bezier curve

Claim 1

An image coding method comprising the steps of: a) extracting an original vertical-horizontal contour of a bi-level image; b) segmenting the contour into a plurality of segments by fitting a predetermined generation curve on each of the segments, said predetermined generation curve being described by control points which include: 1) end control points indicating ends of each segment; and 2) direction control points indicating directions of the fitted curve of each segment at the two ends of each segment; wherein the predetermined generation curve is described by a polynomial MB, in which: ##EQU8## wherein 1) MB denotes a generation point; 2) P0 denotes a starting end control point which indicates a start point of each segment; 3) P1 denotes a start direction control point which indicates a direction of each segment at the start point; 4) P2 denotes an end direction control point which indicates a direction of each segment at an end point of each segment; 5) P3 denotes an ending control point which indicates the end point of each segment; 6) t is a parameter, 0≦t≦1.0; and 7) c and d are arbitrary real numbers; c) coding the control points; d) selecting an optimum curve by choosing particular values for the arbitrary real numbers c and d; and e) determining particular values for control points after the choice of particular values for the real numbers c and d.