model_classifier.trainable = False

这个问题是一个编程类的问题，它是用来让模型的分类器不可调用（即不可训练）的。你可以在训练模型时，冻结分类器，使其不可训练，这有助于避免过拟合和提高模型的性能。如果你想要一个具体的实现，我可以为你提供一个示例。

相关问题

model = densenet121(pretrained=True) num_ftrs = model.classifier.in_features model.classifier = nn.Linear(num_ftrs, 4)与K.set_learning_phase(0) base_model = DenseNet121(weights='imagenet', include_top=False, input_shape=(224, 224, 3), ) for layer in base_model.layers: layer.trainable=False K.set_learning_phase(1) x = base_model.output x = layers.GlobalMaxPooling2D()(x) # let's add a fully-connected layer x = layers.Dense(512, activation='relu', kernel_regularizer=regularizers.l2(0.0001))(x) x = layers.Dense(128, activation='relu', kernel_regularizer=regularizers.l2(0.0001))(x) # and a logistic l # ayer -- let's say we have 200 classes predictions = layers.Dense(4, activation='softmax')(x) model = Model(inputs=base_model.input, outputs=predictions) model.summary()

这是两个不同的深度学习模型的代码。第一个是使用PyTorch实现的DenseNet121模型，将其预训练的分类器替换为一个具有4个输出类的线性层。第二个是使用Keras实现的DenseNet121模型，该模型在ImageNet数据集上进行了预训练，但将其顶部的分类层移除，并添加了几个全连接层和一个softmax层，以适应另一个具有4个输出类的任务。这两个模型采用不同的框架和实现方式，但都使用了DenseNet121作为基础模型，并且都是用于分类任务。

faster rcnn训练自己数据集的代码

Faster R-CNN 是一种基于深度学习的目标检测算法，它可以用于训练自己的数据集。下面是 Faster R-CNN 训练自己数据集的代码示例：

1. 准备训练数据集

首先需要准备训练数据集，包括图像和标注文件。标注文件可以是 VOC 格式或 COCO 格式。

2. 安装依赖库和下载代码

需要安装 TensorFlow 和 Keras，以及下载 Faster R-CNN 的代码。

3. 修改配置文件

修改 Faster R-CNN 的配置文件，包括训练和测试的参数、数据集路径以及模型保存路径等。

4. 训练模型

运行训练代码，使用准备好的数据集进行训练，直到模型收敛或达到预设的训练轮数。

5. 测试模型

使用测试数据集对训练好的模型进行测试，评估模型的准确率和召回率等指标。

6. 模型优化

根据测试结果对模型进行优化，包括调整参数、增加数据集大小等。

参考代码：

以下是 Faster R-CNN 训练自己数据集的代码示例。这里以 TensorFlow 和 Keras 为例，代码中的数据集为 VOC 格式。

# 导入依赖库
import tensorflow as tf
from keras import backend as K
from keras.layers import Input
from keras.models import Model
from keras.optimizers import Adam
from keras.utils import plot_model
from keras.callbacks import TensorBoard, ModelCheckpoint
from keras_frcnn import config
from keras_frcnn import data_generators
from keras_frcnn import losses as losses_fn
from keras_frcnn import roi_helpers
from keras_frcnn import resnet as nn
from keras_frcnn import visualize

# 设置配置文件
config_output_filename = 'config.pickle'
network = 'resnet50'
num_epochs = 1000
output_weight_path = './model_frcnn.hdf5'
input_weight_path = './resnet50_weights_tf_dim_ordering_tf_kernels.h5'
tensorboard_dir = './logs'
train_path = './train.txt'
test_path = './test.txt'
num_rois = 32
horizontal_flips = True
vertical_flips = True
rot_90 = True
output_weight_path = './model_frcnn.hdf5'

# 加载配置文件
config = config.Config()
config_output_filename = 'config.pickle'

# 加载数据集
all_imgs, classes_count, class_mapping = data_generators.get_data(train_path)
test_imgs, _, _ = data_generators.get_data(test_path)

# 计算平均像素值
if 'bg' not in classes_count:
    classes_count['bg'] = 0
    class_mapping['bg'] = len(class_mapping)

config.class_mapping = class_mapping

# 计算平均像素值
C = config.num_channels
mean_pixel = [103.939, 116.779, 123.68]
img_size = (config.im_size, config.im_size)

# 组装模型
input_shape_img = (None, None, C)
img_input = Input(shape=input_shape_img)
roi_input = Input(shape=(num_rois, 4))
shared_layers = nn.nn_base(img_input, trainable=True)

# RPN 网络
num_anchors = len(config.anchor_box_scales) * len(config.anchor_box_ratios)
rpn_layers = nn.rpn(shared_layers, num_anchors)

# RoI 网络
classifier = nn.classifier(shared_layers, roi_input, num_rois, nb_classes=len(classes_count), trainable=True)
model_rpn = Model(img_input, rpn_layers)
model_classifier = Model([img_input, roi_input], classifier)

# 加载权重
model_rpn.load_weights(input_weight_path, by_name=True)
model_classifier.load_weights(input_weight_path, by_name=True)

# 生成训练数据
data_gen_train = data_generators.get_anchor_gt(all_imgs, classes_count, C, K.image_dim_ordering(), mode='train', \
                                               img_size=img_size, \
                                               num_rois=num_rois, \
                                               horizontal_flips=horizontal_flips, \
                                               vertical_flips=vertical_flips, \
                                               rot_90=rot_90)

# 编译模型
optimizer = Adam(lr=1e-5)
model_rpn.compile(optimizer=optimizer, loss=[losses_fn.rpn_loss_cls(num_anchors), losses_fn.rpn_loss_regr(num_anchors)])
model_classifier.compile(optimizer=optimizer, loss=[losses_fn.class_loss_cls, losses_fn.class_loss_regr(len(classes_count) - 1)], metrics={'dense_class_{}'.format(len(classes_count)): 'accuracy'})

# 训练模型
epoch_length = 1000
num_epochs = int(num_epochs)
iter_num = 0

losses = np.zeros((epoch_length, 5))
rpn_accuracy_rpn_monitor = []
rpn_accuracy_for_epoch = []

start_time = time.time()

best_loss = np.Inf

class_mapping_inv = {v: k for k, v in class_mapping.items()}
print('Starting training')

for epoch_num in range(num_epochs):

    progbar = generic_utils.Progbar(epoch_length)
    print('Epoch {}/{}'.format(epoch_num + 1, num_epochs))

    while True:
        try:

            if len(rpn_accuracy_rpn_monitor) == epoch_length and C.verbose:
                mean_overlapping_bboxes = float(sum(rpn_accuracy_rpn_monitor)) / len(rpn_accuracy_rpn_monitor)
                rpn_accuracy_rpn_monitor = []
                print('Average number of overlapping bounding boxes from RPN = {} for {} previous iterations'.format(mean_overlapping_bboxes, epoch_length))
                if mean_overlapping_bboxes == 0:
                    print('RPN is not producing bounding boxes that overlap the ground truth boxes. Check RPN settings or keep training.')

            X, Y, img_data = next(data_gen_train)

            loss_rpn = model_rpn.train_on_batch(X, Y)

            P_rpn = model_rpn.predict_on_batch(X)

            R = roi_helpers.rpn_to_roi(P_rpn[0], P_rpn[1], C.image_dim_ordering(), use_regr=True, overlap_thresh=0.7, max_boxes=300)

            X2, Y1, Y2, IouS = roi_helpers.calc_iou(R, img_data, C, class_mapping)

            if X2 is None:
                rpn_accuracy_rpn_monitor.append(0)
                rpn_accuracy_for_epoch.append(0)
                continue

            # sampling positive/negative samples
            neg_samples = np.where(Y1[0, :, -1] == 1)
            pos_samples = np.where(Y1[0, :, -1] == 0)

            if len(neg_samples) > 0:
                neg_samples = neg_samples[0]
            else:
                neg_samples = []

            if len(pos_samples) > 0:
                pos_samples = pos_samples[0]
            else:
                pos_samples = []

            rpn_accuracy_rpn_monitor.append(len(pos_samples))
            rpn_accuracy_for_epoch.append((len(pos_samples)))

            if C.num_rois > 1:
                if len(pos_samples) < C.num_rois // 2:
                    selected_pos_samples = pos_samples.tolist()
                else:
                    selected_pos_samples = np.random.choice(pos_samples, C.num_rois // 2, replace=False).tolist()
                try:
                    selected_neg_samples = np.random.choice(neg_samples, C.num_rois - len(selected_pos_samples), replace=False).tolist()
                except:
                    selected_neg_samples = np.random.choice(neg_samples, C.num_rois - len(selected_pos_samples), replace=True).tolist()

                sel_samples = selected_pos_samples + selected_neg_samples
            else:
                # in the extreme case where num_rois = 1, we pick a random pos or neg sample
                selected_pos_samples = pos_samples.tolist()
                selected_neg_samples = neg_samples.tolist()
                if np.random.randint(0, 2):
                    sel_samples = random.choice(neg_samples)
                else:
                    sel_samples = random.choice(pos_samples)

            loss_class = model_classifier.train_on_batch([X, X2[:, sel_samples, :]], [Y1[:, sel_samples, :], Y2[:, sel_samples, :]])

            losses[iter_num, 0] = loss_rpn[1]
            losses[iter_num, 1] = loss_rpn[2]

            losses[iter_num, 2] = loss_class[1]
            losses[iter_num, 3] = loss_class[2]
            losses[iter_num, 4] = loss_class[3]

            iter_num += 1

            progbar.update(iter_num, [('rpn_cls', np.mean(losses[:iter_num, 0])), ('rpn_regr', np.mean(losses[:iter_num, 1])),
                                      ('detector_cls', np.mean(losses[:iter_num, 2])),
                                      ('detector_regr', np.mean(losses[:iter_num, 3])),
                                      ('mean_overlapping_bboxes', float(sum(rpn_accuracy_for_epoch)) / len(rpn_accuracy_for_epoch))])

            if iter_num == epoch_length:
                loss_rpn_cls = np.mean(losses[:, 0])
                loss_rpn_regr = np.mean(losses[:, 1])
                loss_class_cls = np.mean(losses[:, 2])
                loss_class_regr = np.mean(losses[:, 3])
                class_acc = np.mean(losses[:, 4])

                mean_overlapping_bboxes = float(sum(rpn_accuracy_for_epoch)) / len(rpn_accuracy_for_epoch)
                rpn_accuracy_for_epoch = []

                if C.verbose:
                    print('Mean number of bounding boxes from RPN overlapping ground truth boxes: {}'.format(mean_overlapping_bboxes))
                    print('Classifier accuracy for bounding boxes from RPN: {}'.format(class_acc))
                    print('Loss RPN classifier: {}'.format(loss_rpn_cls))
                    print('Loss RPN regression: {}'.format(loss_rpn_regr))
                    print('Loss Detector classifier: {}'.format(loss_class_cls))
                    print('Loss Detector regression: {}'.format(loss_class_regr))
                    print('Elapsed time: {}'.format(time.time() - start_time))

                curr_loss = loss_rpn_cls + loss_rpn_regr + loss_class_cls + loss_class_regr

                iter_num = 0
                start_time = time.time()

                if curr_loss < best_loss:
                    if C.verbose:
                        print('Total loss decreased from {} to {}, saving weights'.format(best_loss, curr_loss))
                    best_loss = curr_loss
                    model_rpn.save_weights(output_weight_path)
                    model_classifier.save_weights(output_weight_path)

                break

        except Exception as e:
            print('Exception: {}'.format(e))
            continue

print('Training complete, exiting.')

这是一个简单的 Faster R-CNN 训练自己数据集的示例代码，可以根据自己的数据集和需求进行修改和优化。