冠状面EUV图像中的环分割
Segmentation of Loops from Coronal EUV Images
摘要：
提出了一种从太阳EUV图像中提取亮环特征的方法。在图像强度方面，这些特征是细长的脊状强度最大值。为了区分最大值，我们需要关于图像强度的空间导数的信息。通常，导数估计受到图像噪声的强烈影响。因此，我们使用一个正规化的估计的衍生物，然后用于插入一个离散的矢量场的脊点"脊“，这是定位在脊中心，并具有内在的方向的局部脊方向。提出了一个计划，以连接脊光滑，样条曲线表示的曲线，适合观察到的循环。最后，半自动化的用户界面允许人们合并或分割、消除或选择从上述过程获得的环拟合。在本文中，我们将我们的工具应用于最近发射的STEREO航天器上的SECCHI仪器观测到的第一批EUV图像之一。我们比较提取的环路与投影场线计算从几乎同时采取的SOHO/MDI多普勒成像仪测量的磁图。使用线性无力场模型计算场线。这种比较可以验证我们的分割工具产生的微弱和虚假的环路连接，它也有助于证明磁场模型的质量，其中识别良好的环路结构符合场线投影。我们还讨论了我们的工具，如循环振荡和立体视觉的进一步潜在应用。
英文摘要：
We present a procedure which extracts bright loop features from solar EUV images. In terms of image intensities, these features are elongated ridge-like intensity maxima. To discriminate the maxima, we need information about the spatial derivatives of the image intensity. Commonly, the derivative estimates are strongly affected by image noise. We therefore use a regularized estimation of the derivative which is then used to interpolate a discrete vector field of ridge points ``ridgels'' which are positioned on the ridge center and have the intrinsic orientation of the local ridge direction. A scheme is proposed to connect ridgels to smooth, spline-represented curves which fit the observed loops. Finally, a half-automated user interface allows one to merge or split, eliminate or select loop fits obtained form the above procedure. In this paper we apply our tool to one of the first EUV images observed by the SECCHI instrument onboard the recently launched STEREO spacecraft. We compare the extracted loops with projected field lines computed from almost-simultaneously-taken magnetograms measured by the SOHO/MDI Doppler imager. The field lines were calculated using a linear force-free field model. This comparison allows one to verify faint and spurious loop connections produced by our segmentation tool and it also helps to prove the quality of the magnetic-field model where well-identified loop structures comply with field-line projections. We also discuss further potential applications of our tool such as loop oscillations and stereoscopy.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
