Automatic Auroral Boundary Determination Algorithm with Deep Feature and
Dual Level Set
Abstract
The morphology of the auroral oval is an important geophysical parameter
that can be used to uncover the solar wind-geomagnetic field interaction
process and the intrinsic mechanism. However, it is still a challenging
task to automatically obtain auroral poleward and equatorward boundaries
completely and accurately. In this paper, a new model based on the deep
feature and dual level set method is proposed to extract the auroral
oval boundaries in the images acquired by the Ultraviolet Imager (UVI)
onboard the Polar spacecraft. With the deep feature extracted by the
convolutional neural network (CNN), the corresponding deep feature
energy functional is constructed and incorporated into the variational
segmentation framework. The dual level set method is implemented to
extract the accurate poleward and equatorward boundaries with the
gradient descent flow. The experimental results on the test data set
demonstrate that this model can extract complete auroral oval contours
that are consistent well with expert annotations and owns higher
accuracy compared with the previously proposed methods. Besides, the
comparison between the extracted auroral boundaries and the
precipitating boundaries determined by Defense Meteorological Satellite
Program (DMSP) SSJ precipitating particle data validates that the
proposed method is trustworthy to capture the global morphology of the
auroral ovals.