In the pretrained network, each image had to be normalized by an average image first, and as we know, the nodule images were grayscale images, so they were normalized by one channel (red, green, or blue) only. Experiments were performed with red, green, and blue channels separately, taking one channel at a time and ignoring the other two (i.e., removing the weights and connections of the other two from the CNN). We also used the grayscale image three times to simulate an image with three color channels and did normalization using the appropriate color channel image. 解释

在预训练网络中，每个图像都必须先由平均图像进行归一化处理。由于结节图像是灰度图像，因此只能使用一个通道（红色、绿色或蓝色）进行归一化。我们进行了不同的实验，分别将红色、绿色和蓝色通道分别用于训练，一次只使用一个通道，忽略其他两个通道（即从CNN中删除其他两个通道的权重和连接）；我们还使用灰度图像三次，模拟具有三个颜色通道的图像，并使用相应的颜色通道图像进行归一化处理。