### Abstract

In this investigation, we propose a scheme which integrates the two complementary approaches, i.e., the raster approach and the vector approach, to minimize the number of feature points but still preserve the shape of digital curves with high fidelity. The raster form of the digital curve is first encoded in the Freeman chain code space. Then the second order derivative operator combined with a Gaussian filter is applied to detect zero crossings. The turning points on the curve detected as zero crossings in Freeman chain code space are then transformed to the image space. The second stage is then applying dynamic strip algorithm to further eliminate unnecessary points remaining in the first stage. In order to avoid over- elimination of the points, the maximum length of the strip may also be assigned in the scheme. To quantitatively analyze the performance of the proposed scheme, the perpendicular distance of each point on the original curve to the fitted line segment characterized by the dominant points is calculated. The applicability of the proposed scheme in surface modeling from a contour map is also tested.

Original language | English |
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Title of host publication | Proceedings of SPIE - The International Society for Optical Engineering |

Editors | Heinrich Ebner, Christian Heipke, Konrad Eder |

Pages | 109-115 |

Number of pages | 7 |

Publication status | Published - 1994 Dec 1 |

Event | ISPRS Commission III Symposium: Spatial Information from Digital Photogrammetry and Computer Vision - Munich, Ger Duration: 1994 Sep 5 → 1994 Sep 9 |

### Publication series

Name | Proceedings of SPIE - The International Society for Optical Engineering |
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Volume | 2357 |

ISSN (Print) | 0277-786X |

### Other

Other | ISPRS Commission III Symposium: Spatial Information from Digital Photogrammetry and Computer Vision |
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City | Munich, Ger |

Period | 94-09-05 → 94-09-09 |

### Fingerprint

### All Science Journal Classification (ASJC) codes

- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Computer Science Applications
- Applied Mathematics
- Electrical and Electronic Engineering

### Cite this

*Proceedings of SPIE - The International Society for Optical Engineering*(pp. 109-115). (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 2357).

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*Proceedings of SPIE - The International Society for Optical Engineering.*Proceedings of SPIE - The International Society for Optical Engineering, vol. 2357, pp. 109-115, ISPRS Commission III Symposium: Spatial Information from Digital Photogrammetry and Computer Vision, Munich, Ger, 94-09-05.

**Hybrid approach for extraction of dominant points from digital curves.** / Chen, L. C.; Rau, Jiann-Yeou; Wu, R. H.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

TY - GEN

T1 - Hybrid approach for extraction of dominant points from digital curves

AU - Chen, L. C.

AU - Rau, Jiann-Yeou

AU - Wu, R. H.

PY - 1994/12/1

Y1 - 1994/12/1

N2 - In this investigation, we propose a scheme which integrates the two complementary approaches, i.e., the raster approach and the vector approach, to minimize the number of feature points but still preserve the shape of digital curves with high fidelity. The raster form of the digital curve is first encoded in the Freeman chain code space. Then the second order derivative operator combined with a Gaussian filter is applied to detect zero crossings. The turning points on the curve detected as zero crossings in Freeman chain code space are then transformed to the image space. The second stage is then applying dynamic strip algorithm to further eliminate unnecessary points remaining in the first stage. In order to avoid over- elimination of the points, the maximum length of the strip may also be assigned in the scheme. To quantitatively analyze the performance of the proposed scheme, the perpendicular distance of each point on the original curve to the fitted line segment characterized by the dominant points is calculated. The applicability of the proposed scheme in surface modeling from a contour map is also tested.

AB - In this investigation, we propose a scheme which integrates the two complementary approaches, i.e., the raster approach and the vector approach, to minimize the number of feature points but still preserve the shape of digital curves with high fidelity. The raster form of the digital curve is first encoded in the Freeman chain code space. Then the second order derivative operator combined with a Gaussian filter is applied to detect zero crossings. The turning points on the curve detected as zero crossings in Freeman chain code space are then transformed to the image space. The second stage is then applying dynamic strip algorithm to further eliminate unnecessary points remaining in the first stage. In order to avoid over- elimination of the points, the maximum length of the strip may also be assigned in the scheme. To quantitatively analyze the performance of the proposed scheme, the perpendicular distance of each point on the original curve to the fitted line segment characterized by the dominant points is calculated. The applicability of the proposed scheme in surface modeling from a contour map is also tested.

UR - http://www.scopus.com/inward/record.url?scp=0028755287&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0028755287&partnerID=8YFLogxK

M3 - Conference contribution

SN - 0819416967

T3 - Proceedings of SPIE - The International Society for Optical Engineering

SP - 109

EP - 115

BT - Proceedings of SPIE - The International Society for Optical Engineering

A2 - Ebner, Heinrich

A2 - Heipke, Christian

A2 - Eder, Konrad

ER -