Curve edition system, curve-loop detecting system, curve-loop removing system

• US 6,535,213 B1
• Filed: 09/20/1999
• Issued: 03/18/2003
• Est. Priority Date: 09/22/1998
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Ogino, Tomotaka, Kawamura, Makoto, Totsuka, Takashi
• Primary Examiner(s): Bella, Matthew C.
• Assistant Examiner(s): Sajous, Wesner
• Application Number:
  US09/398,866
• Time in Patent Office: 1,275 Days
• Field of Search: G06/T.700, G06/T.900, G06/T 1.180, G06/T 1.120, H04/N.52775, 345/440, 345/441, 345/442, 345/443, 345/467, 345/468, 345/469, 345/469.1, 345/470, 345/471, 345/472, 345/473, 345/619, 345/621, 345/622, 345/653-655, 345/472.3, 345/474, 382/170-171, 382/177, 382/181, 382/185, 382/193, 382/199, 382/201, 382/202-204, 382/254
• US Class Current: 345/442
• CPC Class Codes: G06T 11/203 Drawing of straight lines or curves

Abstract

Two curves indicating the border of an object in an image are simply edited and loops formed owing to edition of the curves indicating the border of an object in an image are detected and removed. A curve edition apparatus according to the present invention incorporates: converting units for converting two curves indicating positions of inner and outer boundaries of a border of an object included in an image to produce a dot sequence for each curve; a changing unit for changing the coordinates of each point by linking the dot sequence of each curve produced by the converting units; and restructuring units for restructuring the two curves from the coordinates of each point having the coordinates changed by the changing unit. Another aspect incorporates an edition unit for editing the shape of a boundary curve indicating the shape of a border of an object included in an image and formed by a plurality of segments; a first detecting unit for detecting, for each segment, a loop formed owing to an edition process performed by the edition unit; a second detecting unit for detecting a loop formed by a plurality of segments; and loop removing units for removing the loops detected by the first detecting unit and the second detecting unit.

Claims

1. A curve editing apparatus comprising:

edit means for editing the shape of a boundary curve indicating the shape of a border of an object included in an image and formed by a plurality of segments;

first detecting means for detecting, for each segment, a loop formed as a result of an edit process performed by said edit means, the first detecting means comprising a rough determining means for determining whether or not a loop is formed by a single segment by forming a boundary curve indicating the border of an object included in an image and by projecting a vector connecting a terminal point and a control point of each segment, in the form of a Bezier curve defined by the terminal point and the control point, to each other on a straight line so as to detect the direction of the vector, and a precise determining means for determining whether or not a loop is formed by a single segment by dividing the segment which forms the loop, as determined by said rough determining means, and by setting a rectangular region surrounding each segment by connecting to each other the terminal point and the control point of each segment produced as a result of the division process to each other so as to determine whether or not the rectangular regions are superimposed;

second detecting means for detecting a loop formed by a plurality of segments; and

loop removing means for removing the loops detected by said first detecting means and said second detecting means.

2. A curve edition apparatus according to claim 1, wherein said precise determining means calculates the curvature of each segment produced owing to the division process to determine whether or not approximation to a straight line is permitted, and if a determination is made that the approximation to a straight line is permitted, approximation of each segment produced owing to the dividing process to a straight line is performed to calculate an intersection.

3. A curve edition apparatus, comprising:

edit means for editing the shape of a boundary curve indicating the shape of a border of an object included in an image and formed by a plurality of segments;

first detecting means for detecting, for each segment, a loop formed as a result of an edition process performed by said edit means;

second detecting means for detecting a loop formed by a plurality of segments;

loop extracting means which uses information about the intersection indicating that a loop is formed from segments formed by dividing a boundary curve indicating the shape of a border of an object included in an image intersects to extract a plurality of loops in contact with each other at each intersection according to the length of the loops; and

loop removing means for removing the loops detected by said first detecting means and said second detecting means, wherein said loop removing means removes the loops extracted by said loop extracting means.

4. A curve edition apparatus according to claim 3, wherein said loop extracting means extracts a loop having a shortest length among said plurality of loops made contact with one another at each intersection indicated with information about the intersections, and

said loop removing means removes the loop extracted by said loop extracting means to remove loops formed in the boundary curves in an ascending order of the length of the loop.

5. A curve editing method comprising the steps of:

editing the shape of a boundary curve indicating the shape of the border of an object included in an image and formed by a plurality of segments;

detecting, for each segment, a loop formed as a result of the edit by roughly determining whether or not a loop is formed by a single segment by forming a boundary curve indicating the border of an object included in an image and by projecting a vector connecting a terminal point and a control point of each segment, in the form of a Bezier curve defined by the terminal point and the control point, to each other on a straight line so as to detect the direction of the vector, followed by precisely determining whether or not a loop is formed by a single segment by dividing the segment which forms the loop, as roughly determined, and by setting a rectangular region surrounding each segment by connecting to each other the terminal point and the control point of each segment produced as a result of the division process so as to determine whether or not the rectangular region are superimposed;

detecting a loop formed by a plurality of segments; and

removing the loops detected in either said detecting step.

6. A curve edition method, comprising the steps of:

editing the shape of a boundary curve indicating the shape of the border of an object included in an image and formed by a plurality of segments;

detecting, for each segment, a loop formed as a result of said editing step by roughly determining whether or not a loop is formed by a single segment by forming a boundary curve indicating the border of an object included in an image and by projecting a vector connecting a terminal point and a control point of each segment, in the form of a Bezier curve defined by the terminal point and the control point, to each other on a straight line so as to detect the direction of the vector, followed by precisely determining whether or not a loop is formed by a single segment by dividing a segment which forms the loop, as roughly determined, and by setting a rectangular region surrounding each segment by connecting to each other a terminal point and a control point of each segment produced as a result of the division process so as to determine whether or not the rectangular regions are superimposed;

detecting a loop formed by a plurality of segments; and

removing the loops detected in either said detecting step, wherein said precise determining step is adapted to calculate the curvature of each segment produced as a result of a division process to determine whether or not approximation to a straight line is permitted, and if a determination is made that the approximation to a straight line is permitted, approximation of each segment produced as a result of the dividing process to a straight line is performed to calculate an intersection.

7. A curve edition method, comprising the steps of:

editing the shape of a boundary curve indicating the shape of the border of an object included in an image and formed by a plurality of segments;

detecting a loop formed as a result of the editing step for each segment;

detecting a loop formed by a plurality of segments; and

removing the loops detected in either of said detecting steps, wherein said loop removing step is performed by using information about the intersection indicating that a loop is formed from segments formed by dividing a boundary curve indicating the shape of a border of an object included in an image intersects to extract a plurality of loops in contact with each other at each intersection according to the length of the loops so that said plurality of loops made contact with one another at each intersection are removed according to the length of the loop.

8. A curve edition method according to claim 7, wherein said loop removing step is performed such that a loop having a shortest length is extracted among said plurality of loops made contact with one another at each intersection indicated with information about the intersections, and loops formed in the boundary curves are removed in an ascending order of the length of the loop.

9. A curve-loop detecting method comprising the steps of:

roughly determining whether or not a loop is formed by a single segment by forming a boundary curve indicating the border of an object included in an image and by projecting a vector connecting a terminal point and a control point of each segment in the form of a Bezier curve defined by the terminal point and the control point to each other on a straight line so as to detect the direction of the vector;

precisely determining whether or not a loop is formed by a single segment by dividing the segment which forms the loop, as determined in said rough determining step, and by setting a rectangular region surrounding each segment by connecting to each other a terminal point and a control point of each segment produced as a result of the division process, so as to determine whether or not the rectangular regions are imposed, and

indicating if a loop is formed by a single segment.

10. A curve-loop detecting method according to claim 9, said precise determining step is arranged to calculate the curvature of each segment produced owing to the division process to determine whether or not approximation to a straight line is permitted, and if a determination is made that the approximation to a straight line is permitted, approximation of each segment produced owing to the dividing process to a straight line is performed to calculate an intersection.

11. A curve-loop detecting apparatus comprising:

rough determining means for determining whether or not a loop is formed by a single segment by forming a boundary curve indicating the border of an object included in an image and by projecting a vector connecting a terminal point and a control point of each segment in the form of a Bezier curve defined by the terminal point and the control point to each other on a straight line so as to detect the direction of the vector;

precise determining means for determining whether or not a loop is formed by a single segment by dividing the segment which forms the loop, as determined by said rough determining means, and by setting a rectangular region surrounding each segment by connecting to each other a terminal joint and a control point of each segment produced as a result of the division process, so as to determine whether or not the rectangular regions are superimposed;

indicating if a loop is formed by a single segment.

12. A curve-loop detecting apparatus according to claim 11, wherein said precise determining means calculates the curvature of each segment produced owing to the division process to determine whether or not approximation to a straight line is permitted, and if a determination is made that the approximation to a straight line is permitted, approximation of each segment produced owing to the dividing process to a straight line is performed to calculate an intersection.

13. A curve-loop removing method comprising the steps of:

indicating that a loop is formed as a result of an intersection of segments;

extracting the loop utilizing information about the intersection; and

removing the loop extracted by the extracting step.

14. A curve-loop removing method according to claim 13, wherein a loop having a shortest length is extracted among said plurality of loops made contact with one another at each intersection indicated with information about the intersections, and loops formed in the boundary curves are removed in an ascending order of the length of the loop.

15. A curve-loop removing apparatus comprising:

an indicator for indicating that a loop is formed as a result of an intersection of segments;

loop extracting means utilizing information about the intersection to extract the loop; and

loop removing means for removing the loop extracted by the extracting means.

16. A curve-loop removing apparatus according to claim 15, wherein said loop extracting means extracts a loop having a shortest length from said plurality of loops made contact with one another at each intersection indicated with information about the intersections, and

said loop removing means removes the loop extracted by said loop extracting means to remove loops formed in the boundary curves in an ascending order of the length of the loop.