Extracting aurora oval boundary from spacecraft UV imagery is not a trivial problem. The distinction between aurora and background varies depending on the factors such as the date, time of the day, and satellite position. Thresholding technique is a well-known technique for detecting aurora boundary from satellite imagery. In this study, three distinct thresholding algorithms, Mixture Modeling, Fuzzy Sets and Entropy thresholding were applied to a selected set of UV images measured on board Polar satellite to examine their effectiveness in aurora boundary detection. Two thresholding approaches were taken: global thresholding and adaptive thresholding. As expected, adaptive thresholding approach showed better results. In addition to these algorithms, another new algorithm (Edge-Based) was examined using adaptive approach. This thresholding algorithm detects aurora oval by identifying the boundary transition between aurora and background. The results from these different algorithms are presented in this paper.