我正在自学 CNN，并注意到在许多实现中，随着我们在网络中的深入（更靠近输出层），特征图/过滤器的数量会增加。这是什么直觉/原因？这对学习有什么帮助？（来自下面典型 CNN 的示例，从 32 增加到 64 到 128）

net2 = NeuralNet(
    layers=[
        ('input', layers.InputLayer),
        ('conv1', layers.Conv2DLayer),
        ('pool1', layers.MaxPool2DLayer),
        ('conv2', layers.Conv2DLayer),
        ('pool2', layers.MaxPool2DLayer),
        ('conv3', layers.Conv2DLayer),
        ('pool3', layers.MaxPool2DLayer),
        ('hidden4', layers.DenseLayer),
        ('hidden5', layers.DenseLayer),
        ('output', layers.DenseLayer),
        ],
    input_shape=(None, 1, 96, 96),
    conv1_num_filters=32, conv1_filter_size=(3, 3), pool1_pool_size=(2, 2),
    conv2_num_filters=64, conv2_filter_size=(2, 2), pool2_pool_size=(2, 2),
    conv3_num_filters=128, conv3_filter_size=(2, 2), pool3_pool_size=(2, 2),
    hidden4_num_units=500, hidden5_num_units=500,
    output_num_units=30, output_nonlinearity=None,

    update_learning_rate=0.01,
    update_momentum=0.9,

    regression=True,
    max_epochs=1000,
    verbose=1,
    )