Image data processing method for compressing an image by approximating curves using a polynomial

Claim 1

A method of transmitting and receiving image data in a compressed format, the method comprising: a) storing a scanned image as a raster pattern in a pattern storage device; b) extracting a contour of the pattern from the pattern storage device; c) dividing the contour into line portions and curve portions; d) compressing the line portions into an initial point and a terminal point, and compressing the curve portions into first, second, third and fourth vector data, using a procedure including the steps of: 1) defining the initial point as the first vector datum; 2) defining the terminal point as the second vector datum; 3) detecting a first tangent passing through the initial point of the curve portion and making a tangential contact therewith; 4) detecting a second tangent passing through the terminal point of the curve portion and making a tangential contact therewith; 5) detecting a third tangent passing through a point on the curve portion other than the initial and terminal points; 6) defining the third vector datum as the intersection of the first tangent and third tangent; and 7) defining fourth vector datum as the intersection of the second tangent and third tangent; e) storing the first, second, third, and fourth vector data in a vector data storage device; f) transmitting the vector data stored in the vector data storage device; g) receiving the vector data; h) storing the vector data in a vector data storage device; i) forming, from the vector data in the vector data storage device, a curve portion contour based on the vector data and first, second and third tangents defined by the vector data; and reproducing a line portion contour based on initial and terminal points; the forming steps performed in accordance with a polynomial M(X,Y) defined by A(1-t).sup.3 +(cP-(c-3)A)(1-t).sup.2 t+(dQ-(d-3 )E)(1-t).sup.2 +Et.sup.3 wherein A stands for the first vector datum, E stands for the second vector datum, P stands for the third vector datum, Q stands for the fourth vector datum, c and d are predetermined coefficients, and t is a parameter changing its value between zero and one and representing a position on the curve; j) forming a bit map based on the contours; and k) storing the bit map as a pattern in a pattern storage device.

Claim 2

A method of transmitting and receiving image data in a compressed format, the method comprising: a) storing a scanned image as a raster pattern in a pattern storage device; b) extracting a contour of the pattern from the pattern storage device; c) dividing the contour into line portions and curve portions; d) compressing the line portions into an initial point and a terminal point, and compressing the curve portions into first, second, third and fourth vector data, using a procedure including the steps of: 1) defining the initial point as the first vector datum; 2) defining the terminal point as the second vector datum; 3) detecting a first tangent passing through the initial point of the curve portion and making a tangential contact therewith; 4) detecting a second tangent passing through the terminal point of the curve portion and making a tangential contact therewith; 5) detecting a third tangent passing through a point on the curve portion other than the initial and terminal points; 6) defining the third vector datum as the intersection of the first tangent and third tangent; and 7) defining fourth vector datum as the intersection of the second tangent and third tangent; e) storing the first, second, third, and fourth vector data in a vector data storage device; f) transmitting the vector data stored in the vector data storage device; g) receiving the vector data; h) storing the vector data in a vector data storage device; i) forming, from the vector data in the vector data storage device, a curve portion contour based on the vector data and first, second and third tangents defined by the vector data; and reproducing a line portion contour based on initial and terminal points; the forming steps performed in accordance with a polynomial M(X,Y) defined by A(1-t).sup.3 +(cP-(c-3)A)(1-t).sup.2 t+(dQ-(d-3 )E)(1-t).sup.2 +Et.sup.3 wherein A stands for the first vector datum, E stands for the second vector datum, P stands for the third vector datum, Q stands for the fourth vector datum, c and d are predetermined coefficients, and t is a parameter changing its value between zero and one and representing a position on the curve; j) forming a bit map based on the contours; and k) storing the bit map as a pattern in a pattern storage device.

Claim 9

A system for forming an image from compressed image data, the system comprising: a) an input interface for receiving one or more input characters; b) a character data storage device having the compressed image data relating to curve portions, line portions and tangents, each for various predefined characters which may constitute the input characters; c) a program storage device including instructions for producing curve portions and line portions from first, second, third and fourth vector data and initial and terminal points, in accordance with a method including the steps of: 1) defining the initial point as the first vector datum; 2) defining the terminal point as the second vector datum; 3) defining the first tangent as passing through the initial point of the curve portion contour and making a tangential contact therewith; 4) defining the second tangent as passing through the terminal point of the curve portion contour and making a tangential contact therewith; 5) defining the third tangent passing through a point on the curve portion contour other than the initial and terminal points; 6) defining the third vector datum as the intersection of the first tangent and third tangent; and 7) defining fourth vector datum as the intersection of the second tangent and third tangent; d) a processor for reading the compressed image data from the character data storage device, calculating coordinates relating to the curve portions and line portions, and generating contours based on the coordinates; e) a bit map storage device for storing the contours; and f) an output interface for transferring the contours from the bit map storage device to an external display device; wherein said program storage device includes instructions for forming the contours by forming the curve portion contour in accordance with a polynomial M(X,Y) defined by A(1-t).sup.3 +(cP-(c-3)A)(1-t).sup.2 t+(dQ-(d-3)E)(1-t).sup.2 +Et.sup.3 wherein A stands for the first vector datum, E stands for the second vector datum, P stands for the third vector datum, Q stands for the fourth vector datum, c and d are predetermined coefficients, and t is a parameter changing its value between zero and one and representing a position the curve.

Claim 10

A system for forming an image from compressed image data, the system comprising: a) an input interface for receiving one or more input characters; b) a character data storage device having the compressed image data relating to curve portions, line portions and tangents, each for various predefined characters which may constitute the input characters; c) a program storage device including instructions for producing curve portions and line portions from first, second, third and fourth vector data and initial and terminal points, in accordance with a method including the steps of: 1) defining the initial point as the first vector datum; 2) defining the terminal point as the second vector datum; 3) defining the first tangent as passing through the initial point of the curve portion contour and making a tangential contact therewith; 4) defining the second tangent as passing through the terminal point of the curve portion contour and making a tangential contact therewith; 5) defining the third tangent passing through a point on the curve portion contour other than the initial and terminal points; 6) defining the third vector datum as the intersection of the first tangent and third tangent; and 7) defining fourth vector datum as the intersection of the second tangent and third tangent; d) a processor for reading the compressed image data from the character data storage device, calculating coordinates relating to the curve portions and line portions, and generating contours based on the coordinates; e) a bit map storage device for storing the contours; and f) an output interface for transferring the contours from the bit map storage device to an external display device; wherein said program storage device includes instructions for forming the contours by forming the curve portion contour in accordance with a polynomial M(X,Y) defined by A(1-t).sup.3 +(cP-(c-3)A)(1-t).sup.2 t+(dQ-(d-3)E)(1-t).sup.2 +Et.sup.3 wherein A stands for the first vector datum, E stands for the second vector datum, P stands for the third vector datum, Q stands for the fourth vector datum, c and d are predetermined coefficients, and t is a parameter changing its value between zero and one and representing a position the curve.