train_frcnn.py

从config.Config中获取了默认参数：

C = config.Config()

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从get_data中获取了图片、类别计数、类别映射:

all_imgs, classes_count, class_mapping = get_data()

C.class_mapping = class_mapping

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从all_imgs中获取训练集、验证集和测试集的图片：
train_imgs = [s for s in all_imgs if s['imageset'] == 'trainval']

val_imgs = [s for s in all_imgs if s['imageset'] == 'test']

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