원형객체의 기하학적 정보를 이용한 영상분할 알고리즘

Image Segmentation Algorithm Based on Geometric Information of Circular Shape Object

  • 발행 : 2009.12.31

초록

영상분할은 그 결과가 영상의 해석에 있어 매우 중요한 영향을 미치게 되며, 영상 처리의 필수 불가결한 단계이다. 이처럼 영상분할은 그 중요성이 높은 반면에 기존의 영상분할 방법들은 객체 내 픽셀 값의 변화가 심하거나, 객체와 배경과의 경계가 불분명한 경우 영역 분할의 문제를 가져 오게 된다. 이는 다수의 객체들이 서로 인접하여 구성되었을 때 빈번하게 발생하는데, 본 논문은 이러한 다수의 객체들이 원형 성분을 가진 객체들로 이루어 졌을 때 원형객체의 기하학적 정보를 이용하여 단일 객체로 분할하는 알고리즘을 제안한다. 본 논문에서 제안하는 원형객체 분할 알고리즘은 총 4단계로 나누어진다. 그 중 첫단계는 인접한 원형객체의 외곽선 추출을 위한 단계, 두 번째 단계는 앞서 추출된 외곽선 정보를 이용하여 분할 후보점을 추출하는 단계, 세 번째 단계는 분할 후보점을 이용하여 대표 원들을 계산하는 단계, 끝으로 네 번째 단계는 계산된 대표 원들의 확장과 축소를 통하여 겹쳐지는 픽셀들을 기록해 이를 직선으로 연결하는 단계이다. 제안한 알고리즘의 성능 평가를 위해, 본 알고리즘과 목적이 가장 유사한 대표 세포 영상분할 알고리즘 3개와 비교하였고, 평가 방법은 분할된 영역의 개수 차와 내부 분할선의 비교 평가로 이루어졌다. 실험 결과, 가장 좋았던 Yan에 비해 개수 차는 16.7%, 내부 분할선의 정확도 평가는 21.8% 높은 것으로 나타났다.

The result of Image segmentation, an indispensable process in image processing, significantly affects the analysis of an image. Despite the significance of image segmentation, it produces some problems when the variation of pixel values is large, or the boundary between background and an object is not clear. Also, these problems occur frequently when many objects in an image are placed very close by. In this paper, when the shape of objects in an image is circular, we proposed an algorithm which segment an each object in an image using the geometric characteristic of circular shape. The proposed algorithm is composed of 4 steps. First is the boundary edge extraction of whole object. Second step is to find the candidate points for further segmentation using the boundary edge in the first step. Calculating the representative circles using the candidate points is the third step. Final step is to draw the line connecting the overlapped points produced by the several erosions and dilations of the representative circles. To verify the efficiency of the proposed algorithm, the algorithm is compared with the three well-known cell segmentation algorithms. Comparison is conducted by the number of segmented region and the correctness of the inner segment line. As the result, the proposed algorithm is better than the well-known algorithms in both the number of segmented region and the correctness of the inner segment line by 16.7% and 21.8%, respectively.

키워드

참고문헌

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