Computer graphics processing and selective visual display system – Computer graphics processing – Shape generating
Reexamination Certificate
1999-09-20
2003-03-18
Bella, Matthew C. (Department: 2676)
Computer graphics processing and selective visual display system
Computer graphics processing
Shape generating
C345S441000, C345S468000, C345S469000, C345S469100, C382S181000, C382S199000
Reexamination Certificate
active
06535213
ABSTRACT:
BACKGROUND OF THE INVENTION P 1. FIELD OF THE INVENTION
The present invention relates to a curve edition system included in an image processing technique which is employed in an industrial field of a CAD and an image producing field and arranged to edit boundary curves indicating a border of an object included in an image, a curve-loop detecting system for detecting a loop formed owing to edition of the boundary curves, a curve-loop removing system for removing a loop formed by the boundary curves.
2. Description of the Related Art
A conventional technique for producing key signals by extracting the border of an object in an image is a basic and important image processing technique which is applied to a variety of fields including recognition of an object and tracking and synthesis of images. The key signal includes a so-called hard key which uses binary codes such that the value of a foreground image is made to be one and value of a background image is made to be zero. Another key signal is a soft key with which the border of an object is constituted by two border curves and the value of the foreground image and the value of the background are gradually changed from zero to one.
The conventional methods of producing the soft keys have a main step that an adequate inclination is provided for a border portion of each hard key. For example, “IMAGE SYNTHESIZING APPARATUS” disclosed in Japanese Patent Laid-Open No. 60-232787 has a step of extracting only the border portions of an object in accordance with the hard keys to smooth the image. Another method of producing soft keys has a step of using signals of hard keys to subject only the border portions of the object to a process using a low-pass filter to blur away the border portions of the object so as to obtain a smooth image.
In Japanese Patent Laid-Open No. 4-340671, “ANTI-ALIASING METHOD” has been disclosed with which image blocks are set around a certain pixel of interest in the border portion of an object so as to produce soft keys in accordance with patterns of pixels in the foreground images and the background images in the pixel blocks. The soft keys produced by each of the foregoing methods cannot usually overcome motion blur which occurs when an object is moving because uniform inclinations are provided for the border portions of the object.
A conventional method for producing soft keys by factoring in the motion blur of a dynamic image has been disclosed in, for example, Japanese Patent Laid-Open No. 5-153493. The foregoing method has the step of making a present image of a dynamic image and an immediately preceding image to a comparison to obtain the total sum of variations of pixels at each position of an object. In accordance with the magnitude of the variation, the width of the soft key is determined. However, the foregoing method does not permit a user to easily change a curved surface because the curved surface of the soft key is not controlled.
A technique of producing soft keys has been disclosed in Japanese Patent Laid-Open No. 5-236347 under the title of “SOFT-KEY PRODUCING APPARATUS”. According to the foregoing disclosure, soft keys are produced by performing a process for shaving a hard key with an elliptic cone at each point on the border of an object. The foregoing method is performed such that the motion vector of a portion of interest and the gradient of the image are calculated so as to determine the major axis and the minor axis of the ellipse which is the bottom surface of the elliptic cone. The control of the technique for producing soft keys is performed by using the motion vector and the intensity of the edge to determine the major and minor axes. Hence it follows that the reflection of the motion vector and the intensity of the edge on the produced soft key cannot easily be determined. The foregoing technique for producing soft keys has a step of performing an indirect process for producing soft keys by shaving the hard keys in place of direct production of the soft keys. Therefore, the reflection of the control of the produced soft key cannot easily be determined. As a result, the foregoing technique for producing soft keys does not permit a user to easily perform a required change when the user requires change of a portion of the soft keys.
A conventional technique for producing soft keys has been disclosed in Japanese Patent Laid-Open No. 8-331445 under the title of “APPARATUS FOR PRODUCING SOFT KEY”. The foregoing technique for producing soft keys employs curved surfaces to express the border portions. Therefore, the foregoing method is able to correspond to local changes in the widths of the soft keys on the border. A technique for producing soft keys disclosed in Japanese Patent Laid-Open No. 9-37153 under the title of “KEY-SIGNAL CALCULATING APPARATUS AND METHOD THEREFOR” uses changes in the values of pixels to automate calculations of the key signals so as to enable the width of the soft key to be calculated.
The “APPARATUS FOR PRODUCING SOFT KEY” disclosed in Japanese Patent Laid-Open No. 8-331445 and “KEY-SIGNAL CALCULATING APPARATUS AND METHOD THEREFOR” disclosed in Japanese Patent Laid-Open No. 9-37153 have a problem. That is, direct use of the soft key having the width obtained from change in the value of the pixel in a process for synthesizing images results in leakage of the color of the background to the synthesized image. Therefore, edition processes must be performed by a user such that the width of the soft key in the border portion is adjusted and the overall image is moved outwards/inwards.
When a soft key having a width is edited, projection to a flat image display unit is required. When an assumption is made that the mixture ratio of the foreground image and the background image is a, edition is permitted by performing expression using two curves at &agr;=0 and &agr;=1. That is, the two curves form a shape surrounding the border owing to the characteristic of the key curved surface. Therefore, the two curves have a close relationship with the shape of the border of the object. To maintain consistency of the shape of the key curved surface, intersection of the curves must be prevented.
In an example case in which two border curves A
0
and A
1
as shown in
FIG. 1A
are edited to totally and inwards move central line pc′ to central line pc′ as shown in FIG.
1
B and the border curves are A
0
′ and A
1
′, a loop is undesirably formed at the internal border curve A
1
′ of the two border curves A
0
′ and A
1
′. In another example case in which border curves A
0
and A
1
shown in
FIG. 2A
are deformed into border curves A
0
′ and A
1
′ shown in FIG.
2
B and the width is changed from W to W′, also loop is undesirably formed.
To edit two border curves, a method has usually been employed with which each border curve is edited. That is, a uniform process of the two curves cannot be performed. What is worse, the foregoing method has a problem in that the width of the curve is changed unintentionally for a user owing to no relationship with the direction of the border.
SUMMARY OF THE INVENTION
In view of the foregoing, an object of the present invention is to provide a curve edition system which is capable of easily editing two curves indicating the border of an object in an image.
Another object of the present invention is to provide a curve edition, curve loop detection, and curve loop removing system which is capable of detecting and removing a loop formed owing to edition of a curve representing the border of an object in an image.
To achieve the foregoing objects, according to one aspect of the present invention, there is provided a curve edition apparatus comprising: converting means 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; changing means for changing the coordinates of each point by using the dot sequence of each curve produced by the converting means; and restructuring means f
Kawamura Makoto
Ogino Tomotaka
Totsuka Takashi
Bella Matthew C.
Megerditchian Samuel H.
Sajous Wesner
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