  The long-tailed distribution datasets poses great challenges for deep
learning based classification models on how to handle the class imbalance
problem. Existing solutions usually involve class-balacing strategies or
transfer learing from head- to tail-classes or use two-stages learning strategy
to re-train the classifier. However, the existing methods are difficult to
solve the low quality problem when images are obtained by SAR. To address this
problem, we establish a novel three-stages training strategy, which has
excellent results for processing SAR image datasets with long-tailed
distribution. Specifically, we divide training procedure into three stages. The
first stage is to use all kinds of images for rough-training, so as to get the
rough-training model with rich content. The second stage is to make the rough
model learn the feature expression by using the residual dataset with the class
0 removed. The third stage is to fine tune the model using class-balanced
datasets with all 10 classes (including the overall model fine tuning and
classifier re-optimization). Through this new training strategy, we only use
the information of SAR image dataset and the network model with very small
parameters to achieve the top 1 accuracy of 22.34 in development phase.
