本文利用圓形Hough轉換追蹤顆粒流影像及土石流影像中顆粒的移動特性。本文分析的影像包含直立式環筒顆粒流影像及現場土石流影像。
本文在直立式環筒顆粒流試驗中，使用聚苯乙烯顆粒（單一粒徑）及玻璃彈珠（混合粒徑）兩種球形顆粒。使用DV攝影機來拍攝顆粒在環筒中的運動過程，然後使用影像處理、Hough轉換及PTV技術追蹤顆粒在影像中的位置及運動軌跡。結果表明只要影像中顆粒的邊緣足夠清晰且影像中的顆粒粒徑大小需大於8個像素，即使顆粒的材質不同，本文所使用的方法都能有效追蹤顆粒的運動軌跡。圓形的Hough轉換除了可以得到顆粒在影像中的位置，也可求得顆粒的半徑大小，有利於分析混合粒徑顆粒流中顆粒大小及其運動特性。
本文運用影像處理、Hough轉換及PTV技術追蹤分析土石流影像中表面較大的礫石顆粒的運動特性。結果表明由於土石流中礫石顆粒並非圓形，雖然理論上不宜直接使用圓形Hough轉換，但可以求取內切圓或外切圓的方式進行追蹤分析。在應用於土石流的影像時，若將整張影像做Hough轉換，將得到許多不必要的點位資料，而本文尚未找到合適的資料篩選方式。若改對選取之ROI範圍(region of interest)影像中的顆粒定位，則有不錯的結果，由不同時間點的影像求得的顆粒位置，可來用來估算出土石流的表面顆粒的移動速度。

This paper presents a method of using circular Hough transform to identify the positions of particles in an image of granular flow or debris flow and then to track their moving trajectories. The images used in this paper includes the video image of granular flows in a vertically rotating annular flume experiments, and the video image of a debris flow.
The experiments of granular flows in a vertically rotating annular flume were conducted by using two types of spherical granular particles：polystyrene pellets (having uniform size) and glass marbles (having non-uniform size). The spherical particles moving in the rotating annular flume were recorded by a digital video camera. The positions of particles in the image were identified by the techniques of the digital image processing, the Hough transform and the particle tracking velocimetry (PTV). The result showed that as long as the particle size in the image is larger than eight pixels and the edge of particles in the image is clear, the proposed method can effectively track the moving particles for the two kinds of particle materials used in this study. The circular Hough transform not only can identify the position of particle but also can estimate the diameter of the particle, and this function would be very useful in analysis of the particle sizes and size distribution in the granular flows with non-uniform particle sizes.
The proposed method of particle tracking was also applied to analyze the movement of the large gravels on the surface of a debris flow. Theoretically, the circular Hough transform could not directly used to track the gravels in debris flows because gravels in the flows are not spherical in shape. Therefore, the non-circular shape technique of circular Hough transform was used track the gravels in debris flows. If taking the Hough transform on the entire image of a debris flow, it would get many unnecessary data, and the author had not found a suitable method to delete these unnecessary data yet. Therefore, the author take the Hough transform on the region of interest of the debris-flow image instead of the entire image in tracking the gravel movement in debris flow.

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