Parametric curves such as Bézier and B-splines, originally developedfor the design of automobile bodies, are now also used in image processing andcomputer vision. For example, reconstructing an object shape in an...Parametric curves such as Bézier and B-splines, originally developedfor the design of automobile bodies, are now also used in image processing andcomputer vision. For example, reconstructing an object shape in an image,including different translations, scales, and orientations, can be performedusing these parametric curves. For this, Bézier and B-spline curves can be generatedusing a point set that belongs to the outer boundary of the object. Theresulting object shape can be used in computer vision fields, such as searchingand segmentation methods and training machine learning algorithms. Theprerequisite for reconstructing the shape with parametric curves is to obtainsequentially the points in the point set. In this study, a novel algorithm hasbeen developed that sequentially obtains the pixel locations constituting theouter boundary of the object. The proposed algorithm, unlike the methods inthe literature, is implemented using a filter containing weights and an outercircle surrounding the object. In a binary format image, the starting point ofthe tracing is determined using the outer circle, and the next tracing movementand the pixel to be labeled as the boundary point is found by the filter weights.Then, control points that define the curve shape are selected by reducing thenumber of sequential points. Thus, the Bézier and B-spline curve equationsdescribing the shape are obtained using these points. In addition, differenttranslations, scales, and rotations of the object shape are easily provided bychanging the positions of the control points. It has also been shown that themissing part of the object can be completed thanks to the parametric curves.展开更多
The application of digital image analysis to calculate the parameters of softwood cells and to understand their microstructure is of importance in the area of basic micro-wood research such as wood anatomy. In order t...The application of digital image analysis to calculate the parameters of softwood cells and to understand their microstructure is of importance in the area of basic micro-wood research such as wood anatomy. In order to obtain cell parameters, the most important part is to separate the cells from their background in an image, which is accomplished by drawing cell contours. In this study, a contour tracing method based on digital image binarization is introduced to extract the contours of softwood cells. As well, a comparison with other traditional methods is included. The results show that using this contour tracing method, clear and complete contours can be obtained, which solves the problems of traditional methods where sharp comers and turning points in an image could not be addressed.展开更多
This paper presents an algorithm for extracting lines from hand drawings.It starts from contour pixel tracing, fits them into contour segments, and thenextracts skeleton lines from the contour segments. The algorithm ...This paper presents an algorithm for extracting lines from hand drawings.It starts from contour pixel tracing, fits them into contour segments, and thenextracts skeleton lines from the contour segments. The algorithm finds all con-tours in one scan of the input matrix without detecting and marking multiplepixels. In line extraction, the method Elastic Contour Segment nacing is pro-posed which extracts lines by referring to the contour segments at both sides,overcoming noise and passing through blotted areas by fitting and extrapolation.Experiments on free hand mechanical drawings, sketches, letter/numerals,as well as Chinese characters are carried out and satisfactory results are achieved.展开更多
文摘Parametric curves such as Bézier and B-splines, originally developedfor the design of automobile bodies, are now also used in image processing andcomputer vision. For example, reconstructing an object shape in an image,including different translations, scales, and orientations, can be performedusing these parametric curves. For this, Bézier and B-spline curves can be generatedusing a point set that belongs to the outer boundary of the object. Theresulting object shape can be used in computer vision fields, such as searchingand segmentation methods and training machine learning algorithms. Theprerequisite for reconstructing the shape with parametric curves is to obtainsequentially the points in the point set. In this study, a novel algorithm hasbeen developed that sequentially obtains the pixel locations constituting theouter boundary of the object. The proposed algorithm, unlike the methods inthe literature, is implemented using a filter containing weights and an outercircle surrounding the object. In a binary format image, the starting point ofthe tracing is determined using the outer circle, and the next tracing movementand the pixel to be labeled as the boundary point is found by the filter weights.Then, control points that define the curve shape are selected by reducing thenumber of sequential points. Thus, the Bézier and B-spline curve equationsdescribing the shape are obtained using these points. In addition, differenttranslations, scales, and rotations of the object shape are easily provided bychanging the positions of the control points. It has also been shown that themissing part of the object can be completed thanks to the parametric curves.
基金supported by the Key Projects of the National Forestry Bureau (No. 2006-56).
文摘The application of digital image analysis to calculate the parameters of softwood cells and to understand their microstructure is of importance in the area of basic micro-wood research such as wood anatomy. In order to obtain cell parameters, the most important part is to separate the cells from their background in an image, which is accomplished by drawing cell contours. In this study, a contour tracing method based on digital image binarization is introduced to extract the contours of softwood cells. As well, a comparison with other traditional methods is included. The results show that using this contour tracing method, clear and complete contours can be obtained, which solves the problems of traditional methods where sharp comers and turning points in an image could not be addressed.
文摘This paper presents an algorithm for extracting lines from hand drawings.It starts from contour pixel tracing, fits them into contour segments, and thenextracts skeleton lines from the contour segments. The algorithm finds all con-tours in one scan of the input matrix without detecting and marking multiplepixels. In line extraction, the method Elastic Contour Segment nacing is pro-posed which extracts lines by referring to the contour segments at both sides,overcoming noise and passing through blotted areas by fitting and extrapolation.Experiments on free hand mechanical drawings, sketches, letter/numerals,as well as Chinese characters are carried out and satisfactory results are achieved.
