以resnet作为前置网络的ssd目标提取检测
1.目标
本文的目标是将resnet结构作为前置网络,在imagenet数据集上进行预训练,随后将ssd目标提取检测网络(一部分)接在resnet前置网络之后,形成一个完整的ssd网络。
ssd网络下载和配置参考点击打开链接
2.resnet前置网络pretrain
2.1 利用imagenet数据生成lmdb,采用create_imagenet.sh生成,内容如下:
生成的过程采用TRAIN_DATA_ROOT下的图片,具体的图片目录在train.txt中:
- #!/usr/bin/env sh
- # Create the imagenet lmdb inputs
- # N.B. set the path to the imagenet train + val data dirs
- set -e
- EXAMPLE=models/resnet
- DATA=/home/jzhang/data/VOCdevkit/VOC2007
- TOOLS=build/tools
- TRAIN_DATA_ROOT=/home/jzhang/data/VOCdevkit/VOC2007/JPEGImages/
- # Set RESIZE=true to resize the images to 256x256. Leave as false if images have
- # already been resized using another tool.
- RESIZE=true
- if $RESIZE; then
- RESIZE_HEIGHT=224
- RESIZE_WIDTH=224
- else
- RESIZE_HEIGHT=0
- RESIZE_WIDTH=0
- fi
- if [ ! -d "$TRAIN_DATA_ROOT" ]; then
- echo "Error: TRAIN_DATA_ROOT is not a path to a directory: $TRAIN_DATA_ROOT"
- echo "Set the TRAIN_DATA_ROOT variable in create_imagenet.sh to the path" \
- "where the ImageNet training data is stored."
- exit 1
- fi
- echo "Creating train lmdb..."
- GLOG_logtostderr=1 $TOOLS/convert_imageset \
- --resize_height=$RESIZE_HEIGHT \
- --resize_width=$RESIZE_WIDTH \
- --shuffle \
- $TRAIN_DATA_ROOT \
- $DATA/train.txt \
- $EXAMPLE/resnet_train_lmdb
- echo "Done."
train.txt的内容大致如下:
- 000001.jpg 0
- 000002.jpg 1
- 000003.jpg 2
- 000004.jpg 3
- 000005.jpg 4
- 000006.jpg 5
- 000007.jpg 6
- 000008.jpg 7
- 000009.jpg 8
- 000010.jpg 9
运行create_imagenet.sh后就会在EXAMPLE目录下生成lmdb文件夹,其中包含data.mdb和lock.mdb。这些都是caffe需要使用的数据格式。
2.2 编写solver和prototxt
先写各层网络结构的定义res_pretrain.prototxt:
- name: "ResNet-50"
- layer {
- name: "imagenet"
- type: "Data"
- top: "data"
- top: "label"
- include {
- phase: TRAIN
- }
- data_param {
- source: "models/resnet/resnet_train_lmdb" //刚才产生的train的lmdb
- batch_size: 8
- backend: LMDB
- }
- }
- layer {
- name: "imagenet"
- type: "Data"
- top: "data"
- top: "label"
- include {
- phase: TEST
- }
- data_param {
- source: "models/resnet/resnet_test_lmdb" //同理可以产生的test的lmdb
- batch_size: 1
- backend: LMDB
- }
- }
- /////////////////////////////////////////////////////////////////
- //// resnet结构 ////
- /////////////////////////////////////////////////////////////////
- layer {
- bottom: "data"
- top: "conv1"
- name: "conv1"
- type: "Convolution"
- convolution_param {
- num_output: 64
- kernel_size: 7
- pad: 3
- stride: 2
- }
- }
- layer {
- bottom: "conv1"
- top: "conv1"
- name: "bn_conv1"
- type: "BatchNorm"
- batch_norm_param {
- use_global_stats: true
- }
- }
- layer {
- bottom: "conv1"
- top: "conv1"
- name: "scale_conv1"
- type: "Scale"
- scale_param {
- bias_term: true
- }
- }
- layer {
- bottom: "conv1"
- top: "conv1"
- name: "conv1_relu"
- type: "ReLU"
- }
- layer {
- bottom: "conv1"
- top: "pool1"
- name: "pool1"
- type: "Pooling"
- pooling_param {
- kernel_size: 3
- stride: 2
- pool: MAX
- }
- }
- layer {
- bottom: "pool1"
- top: "res2a_branch1"
- name: "res2a_branch1"
- type: "Convolution"
- convolution_param {
- num_output: 256
- kernel_size: 1
- pad: 0
- stride: 1
- bias_term: false
- }
- }
- layer {
- bottom: "res2a_branch1"
- top: "res2a_branch1"
- name: "bn2a_branch1"
- type: "BatchNorm"
- batch_norm_param {
- use_global_stats: true
- }
- }
- //...............................
- layer {
- bottom: "res5c_branch2a"
- top: "res5c_branch2a"
- name: "bn5c_branch2a"
- type: "BatchNorm"
- batch_norm_param {
- use_global_stats: true
- }
- }
- layer {
- bottom: "res5c_branch2a"
- top: "res5c_branch2a"
- name: "scale5c_branch2a"
- type: "Scale"
- scale_param {
- bias_term: true
- }
- }
- layer {
- bottom: "res5c_branch2a"
- top: "res5c_branch2a"
- name: "res5c_branch2a_relu"
- type: "ReLU"
- }
- layer {
- bottom: "res5c_branch2a"
- top: "res5c_branch2b"
- name: "res5c_branch2b"
- type: "Convolution"
- convolution_param {
- num_output: 512
- kernel_size: 3
- pad: 1
- stride: 1
- bias_term: false
- }
- }
- layer {
- bottom: "res5c_branch2b"
- top: "res5c_branch2b"
- name: "bn5c_branch2b"
- type: "BatchNorm"
- batch_norm_param {
- use_global_stats: true
- }
- }
- layer {
- bottom: "res5c_branch2b"
- top: "res5c_branch2b"
- name: "scale5c_branch2b"
- type: "Scale"
- scale_param {
- bias_term: true
- }
- }
- layer {
- bottom: "res5c_branch2b"
- top: "res5c_branch2b"
- name: "res5c_branch2b_relu"
- type: "ReLU"
- }
- layer {
- bottom: "res5c_branch2b"
- top: "res5c_branch2c"
- name: "res5c_branch2c"
- type: "Convolution"
- convolution_param {
- num_output: 2048
- kernel_size: 1
- pad: 0
- stride: 1
- bias_term: false
- }
- }
- layer {
- bottom: "res5c_branch2c"
- top: "res5c_branch2c"
- name: "bn5c_branch2c"
- type: "BatchNorm"
- batch_norm_param {
- use_global_stats: true
- }
- }
- layer {
- bottom: "res5c_branch2c"
- top: "res5c_branch2c"
- name: "scale5c_branch2c"
- type: "Scale"
- scale_param {
- bias_term: true
- }
- }
- layer {
- bottom: "res5b"
- bottom: "res5c_branch2c"
- top: "res5c"
- name: "res5c"
- type: "Eltwise"
- }
- layer {
- bottom: "res5c"
- top: "res5c"
- name: "res5c_relu"
- type: "ReLU"
- }
- layer {
- bottom: "res5c"
- top: "pool5"
- name: "pool5"
- type: "Pooling"
- pooling_param {
- kernel_size: 7
- stride: 1
- pool: AVE
- }
- }
- layer {
- bottom: "pool5"
- top: "fc1000"
- name: "fc1000"
- type: "InnerProduct"
- inner_product_param {
- num_output: 1000
- }
- }
- //loss function
- layer {
- name: "accuracy"
- type: "Accuracy"
- bottom: "fc1000"
- bottom: "label"
- top: "accuracy"
- include {
- phase: TEST
- }
- }
- layer {
- name: "loss"
- type: "SoftmaxWithLoss"
- bottom: "fc1000"
- bottom: "label"
- top: "loss"
- }
写好了网络层的prototxt之后,写solver,res_pretrain_solver.prototxt内容如下:
- net: "models/resnet/res_pretrain.prototxt" //上一步中写的网络层次结构
- test_iter: 10
- test_interval: 10
- base_lr: 0.01 //基础学习率 learning-rate
- lr_policy: "step" //学习策略
- gamma: 0.1
- stepsize: 100000
- display: 20
- max_iter: 450000 //迭代次数
- momentum: 0.9 //学习率衰减系数
- weight_decay: 0.0005 //权重衰减系数,防止过拟合
- snapshot: 1000 //每1000次迭代保存一次参数中间结果
- snapshot_prefix: "models/resnet/resnet_train"
- solver_mode: CPU
2.3 进行pretrain训练
在caffe目录下运行
- ./build/tools/caffe train --solver=models/resnet/res_pretrain_solver.prototxt
solver=之后写的是上面的prototxt地址。
至此,在imagenet上的预训练到此为止。训练之后会生成一个caffemodel,这就是之后需要接到ssd之前网络的参数。
3.接入ssd网络
ssd网络finetuning的流程与之前pretrain基本一致。
3.1产生lmdb
ssd使用的lmdb与之前略有不同。
其train.txt文件下不再是图片对应类型,因为有boundingbox的存在, 所以一个图片对应一个xml文件,如下:
- VOC2007/JPEGImages/000001.jpg VOC2007/Annotations/000001.xml
- VOC2007/JPEGImages/000002.jpg VOC2007/Annotations/000002.xml
- VOC2007/JPEGImages/000003.jpg VOC2007/Annotations/000003.xml
- VOC2007/JPEGImages/000004.jpg VOC2007/Annotations/000004.xml
- VOC2007/JPEGImages/000006.jpg VOC2007/Annotations/000006.xml
- VOC2007/JPEGImages/000008.jpg VOC2007/Annotations/000008.xml
- VOC2007/JPEGImages/000010.jpg VOC2007/Annotations/000010.xml
- VOC2007/JPEGImages/000011.jpg VOC2007/Annotations/000011.xml
- VOC2007/JPEGImages/000013.jpg VOC2007/Annotations/000013.xml
- VOC2007/JPEGImages/000014.jpg VOC2007/Annotations/000014.xml
- cd $root_dir
- redo=1
- data_root_dir="$HOME/data/VOCdevkit"
- dataset_name="VOC0712"
- mapfile="$root_dir/data/$dataset_name/labelmap_voc.prototxt"
- anno_type="detection"
- db="lmdb"
- min_dim=0
- max_dim=0
- width=0
- height=0
- extra_cmd="--encode-type=jpg --encoded"
- if [ $redo ]
- then
- extra_cmd="$extra_cmd --redo"
- fi
- for subset in test trainval
- do
- python $root_dir/scripts/create_annoset.py --anno-type=$anno_type --label-map-file=$mapfile --min-dim=$min_dim --max-dim=$max_dim
- --resize-width=$width --resize-height=$height --check-label $extra_cmd $data_root_dir $root_dir/data/$dataset_name/$subset.txt
- $data_root_dir/$dataset_name/$db/$dataset_name"_"$subset"_"$db examples/$dataset_name
- done
3.2 编写solver和prototxt
首先定义ssd网络层次结构ssd_finetuning.prototxt:
- //ssd中输入层的定义非常复杂,但其中只有一些需要改动,其余的照搬就行
- layer {
- name: "data"
- type: "AnnotatedData"
- top: "data"
- top: "label"
- include {
- phase: TRAIN
- }
- transform_param {
- mirror: true
- mean_value: 104
- mean_value: 117
- mean_value: 123
- resize_param {
- prob: 1
- resize_mode: WARP
- height: 300
- width: 300
- interp_mode: LINEAR
- interp_mode: AREA
- interp_mode: NEAREST
- interp_mode: CUBIC
- interp_mode: LANCZOS4
- }
- emit_constraint {
- emit_type: CENTER
- }
- }
- data_param {
- source: "models/resnet/<span style="font-size:14px;">ssd_train_lmdb</span>" //刚才生成的新的lmdb
- batch_size: 32
- backend: LMDB
- }
- annotated_data_param {
- batch_sampler {
- max_sample: 1
- max_trials: 1
- }
- batch_sampler {
- sampler {
- min_scale: 0.3
- max_scale: 1.0
- min_aspect_ratio: 0.5
- max_aspect_ratio: 2.0
- }
- sample_constraint {
- min_jaccard_overlap: 0.1
- }
- max_sample: 1
- max_trials: 50
- }
- batch_sampler {
- sampler {
- min_scale: 0.3
- max_scale: 1.0
- min_aspect_ratio: 0.5
- max_aspect_ratio: 2.0
- }
- sample_constraint {
- min_jaccard_overlap: 0.3
- }
- max_sample: 1
- max_trials: 50
- }
- batch_sampler {
- sampler {
- min_scale: 0.3
- max_scale: 1.0
- min_aspect_ratio: 0.5
- max_aspect_ratio: 2.0
- }
- sample_constraint {
- min_jaccard_overlap: 0.5
- }
- max_sample: 1
- max_trials: 50
- }
- batch_sampler {
- sampler {
- min_scale: 0.3
- max_scale: 1.0
- min_aspect_ratio: 0.5
- max_aspect_ratio: 2.0
- }
- sample_constraint {
- min_jaccard_overlap: 0.7
- }
- max_sample: 1
- max_trials: 50
- }
- batch_sampler {
- sampler {
- min_scale: 0.3
- max_scale: 1.0
- min_aspect_ratio: 0.5
- max_aspect_ratio: 2.0
- }
- sample_constraint {
- min_jaccard_overlap: 0.9
- }
- max_sample: 1
- max_trials: 50
- }
- batch_sampler {
- sampler {
- min_scale: 0.3
- max_scale: 1.0
- min_aspect_ratio: 0.5
- max_aspect_ratio: 2.0
- }
- sample_constraint {
- max_jaccard_overlap: 1.0
- }
- max_sample: 1
- max_trials: 50
- }
- label_map_file: "data/VOC0712/labelmap_voc.prototxt"
- }
- }
- //resnet结构
- layer {
- bottom: "data"
- top: "conv1"
- name: "conv1"
- type: "Convolution"
- convolution_param {
- num_output: 64
- kernel_size: 7
- pad: 3
- stride: 2
- }
- }
- layer {
- bottom: "conv1"
- top: "conv1"
- name: "bn_conv1"
- type: "BatchNorm"
- batch_norm_param {
- use_global_stats: true
- }
- }
- layer {
- bottom: "data"
- top: "conv1"
- name: "conv1"
- type: "Convolution"
- convolution_param {
- num_output: 64
- kernel_size: 7
- pad: 3
- stride: 2
- }
- }
- //省略很多resnet层
- layer {
- bottom: "res5c"
- top: "res5c"
- name: "res5c_relu"
- type: "ReLU"
- }
- layer {
- bottom: "res5c"
- top: "pool5"
- name: "pool5"
- type: "Pooling"
- pooling_param {
- kernel_size: 7
- stride: 1
- pool: AVE
- }
- }
- //至此resnet主体结构完成,随后接上ssd的结构
- //用pool5作为bottom分别产生mbox_loc/mbox_conf/mbox_priorbox
- layer {
- name: "pool5_mbox_loc"
- type: "Convolution"
- bottom: "pool5" //选取pool5作为bottom,产生mbox_loc
- top: "pool5_mbox_loc"
- param {
- lr_mult: 1
- decay_mult: 1
- }
- param {
- lr_mult: 2
- decay_mult: 0
- }
- convolution_param {
- num_output: 24
- pad: 1
- kernel_size: 3
- stride: 1
- weight_filler {
- type: "xavier"
- }
- bias_filler {
- type: "constant"
- value: 0
- }
- }
- }
- layer {
- name: "pool5_mbox_loc_perm" //将上一层产生的mbox_loc重新排序
- type: "Permute"
- bottom: "pool5_mbox_loc"
- top: "pool5_mbox_loc_perm"
- permute_param {
- order: 0
- order: 2
- order: 3
- order: 1
- }
- }
- layer {
- name: "pool5_mbox_loc_flat" //将上一层展平(例如7*7的展平成1*49,方便之后的拼接)
- type: "Flatten"
- bottom: "pool5_mbox_loc_perm"
- top: "pool5_mbox_loc_flat"
- flatten_param {
- axis: 1
- }
- }
- layer {
- name: "pool5_mbox_conf"
- type: "Convolution"
- bottom: "pool5" //选取pool5作为bottom,产生mbox_conf(之后的排序展平同理)
- top: "pool5_mbox_conf"
- param {
- lr_mult: 1
- decay_mult: 1
- }
- param {
- lr_mult: 2
- decay_mult: 0
- }
- convolution_param {
- num_output: 126
- pad: 1
- kernel_size: 3
- stride: 1
- weight_filler {
- type: "xavier"
- }
- bias_filler {
- type: "constant"
- value: 0
- }
- }
- }
- layer {
- name: "pool5_mbox_conf_perm"
- type: "Permute"
- bottom: "pool5_mbox_conf"
- top: "pool5_mbox_conf_perm"
- permute_param {
- order: 0
- order: 2
- order: 3
- order: 1
- }
- }
- layer {
- name: "pool5_mbox_conf_flat"
- type: "Flatten"
- bottom: "pool5_mbox_conf_perm"
- top: "pool5_mbox_conf_flat"
- flatten_param {
- axis: 1
- }
- }
- layer {
- name: "pool5_mbox_priorbox"
- type: "PriorBox"
- bottom: "pool5" //选取pool5作为bottom,产生mbox_priorbox(之后排序展平)
- bottom: "data"
- top: "pool5_mbox_priorbox"
- prior_box_param {
- min_size: 276.0
- max_size: 330.0
- aspect_ratio: 2
- aspect_ratio: 3
- flip: true
- clip: true
- variance: 0.1
- variance: 0.1
- variance: 0.2
- variance: 0.2
- }
- }
- //同理用res5c作为bottom分别产生mbox_loc/mbox_conf/mbox_priorbox
- layer {
- name: "res5c_mbox_loc"
- type: "Convolution"
- bottom: "res5c"
- top: "res5c_mbox_loc"
- param {
- lr_mult: 1
- decay_mult: 1
- }
- param {
- lr_mult: 2
- decay_mult: 0
- }
- convolution_param {
- num_output: 24
- pad: 1
- kernel_size: 3
- stride: 1
- weight_filler {
- type: "xavier"
- }
- bias_filler {
- type: "constant"
- value: 0
- }
- }
- }
- layer {
- name: "res5c_mbox_loc_perm"
- type: "Permute"
- bottom: "res5c_mbox_loc"
- top: "res5c_mbox_loc_perm"
- permute_param {
- order: 0
- order: 2
- order: 3
- order: 1
- }
- }
- layer {
- name: "res5c_mbox_loc_flat"
- type: "Flatten"
- bottom: "res5c_mbox_loc_perm"
- top: "res5c_mbox_loc_flat"
- flatten_param {
- axis: 1
- }
- }
- layer {
- name: "res5c_mbox_conf"
- type: "Convolution"
- bottom: "res5c"
- top: "res5c_mbox_conf"
- param {
- lr_mult: 1
- decay_mult: 1
- }
- param {
- lr_mult: 2
- decay_mult: 0
- }
- convolution_param {
- num_output: 126
- pad: 1
- kernel_size: 3
- stride: 1
- weight_filler {
- type: "xavier"
- }
- bias_filler {
- type: "constant"
- value: 0
- }
- }
- }
- layer {
- name: "res5c_mbox_conf_perm"
- type: "Permute"
- bottom: "res5c_mbox_conf"
- top: "res5c_mbox_conf_perm"
- permute_param {
- order: 0
- order: 2
- order: 3
- order: 1
- }
- }
- layer {
- name: "res5c_mbox_conf_flat"
- type: "Flatten"
- bottom: "res5c_mbox_conf_perm"
- top: "res5c_mbox_conf_flat"
- flatten_param {
- axis: 1
- }
- }
- layer {
- name: "res5c_mbox_priorbox"
- type: "PriorBox"
- bottom: "res5c"
- bottom: "data"
- top: "res5c_mbox_priorbox"
- prior_box_param {
- min_size: 276.0
- max_size: 330.0
- aspect_ratio: 2
- aspect_ratio: 3
- flip: true
- clip: true
- variance: 0.1
- variance: 0.1
- variance: 0.2
- variance: 0.2
- }
- }
- //Concat层将刚才的res5c和pool5产生的mbox_loc/mbox_conf/mbox_priorbox拼接起来形成一个层
- layer {
- name: "mbox_loc"
- type: "Concat"
- bottom: "res5c_mbox_loc_flat"
- bottom: "pool5_mbox_loc_flat"
- top: "mbox_loc"
- concat_param {
- axis: 1
- }
- }
- layer {
- name: "mbox_conf"
- type: "Concat"
- bottom: "res5c_mbox_conf_flat"
- bottom: "pool5_mbox_conf_flat"
- top: "mbox_conf"
- concat_param {
- axis: 1
- }
- }
- layer {
- name: "mbox_priorbox"
- type: "Concat"
- bottom: "res5c_mbox_priorbox"
- bottom: "pool5_mbox_priorbox"
- top: "mbox_priorbox"
- concat_param {
- axis: 2
- }
- }
- <span style="color:#ff0000;">//mbox_loc,mbox_conf,mbox_priorbox一起做的loss-function</span>
- layer {
- name: "mbox_loss"
- type: "MultiBoxLoss"
- bottom: "mbox_loc"
- bottom: "mbox_conf"
- bottom: "mbox_priorbox"
- bottom: "label"
- top: "mbox_loss"
- include {
- phase: TRAIN
- }
- propagate_down: true
- propagate_down: true
- propagate_down: false
- propagate_down: false
- loss_param {
- normalization: VALID
- }
- multibox_loss_param {
- loc_loss_type: SMOOTH_L1
- conf_loss_type: SOFTMAX
- loc_weight: 1.0
- num_classes: 21
- share_location: true
- match_type: PER_PREDICTION
- overlap_threshold: 0.5
- use_prior_for_matching: true
- background_label_id: 0
- use_difficult_gt: true
- do_neg_mining: true
- neg_pos_ratio: 3.0
- neg_overlap: 0.5
- code_type: CENTER_SIZE
- }
- }
ssd中,mbox_loc层产生x,y,w,h四个值,mbox_conf对于每一个分类都有一个值,如果有20个分类,那就会产生20个值。
对于刚才的prototxt中,res5c层的尺寸为7*7,每一个像素会产生6个boundingbox,pool5层的尺寸为1*1,每一个像素会产生6个boundingbox。总共是7*7*6+1*1*6个候选的boundingbox。
如果需要增加候选的数量,那么就和pool5一样,在resnet中任意选取中间层randomlayer,在这些层之后加入randomlayer_mbox_loc/randomlayer_mbox_conf/randomlayer_mbox_priorbox,最终将这些层都展平并拼接在一起。
至此,ssd的整体网络结构prototxt已经编写完成。对于solver,与之前没有什么区别,ssd_finetuning_solver:
- net: "models/resnet/ssd_finetuning.prototxt"
- base_lr: 0.01
- lr_policy: "step"
- gamma: 0.1
- stepsize: 100000
- display: 20
- max_iter: 450000
- momentum: 0.9
- weight_decay: 0.0005
- snapshot: 10000
- snapshot_prefix: "models/resnet/resnet_train"
- solver_mode: CPU
3.3 训练网络
在caffe目录下运行:
- ./build/tools/caffe train --solver=models/resnet/ssd_finetuning_solver.prototxt -weights models/resnet/res_pretrain.caffemodel
solver=之后加solver地址, weights参数后加预训练pretrain中res_pretrain.caffemodel的参数。
至此,就将pretrain好的resnet网络接入了ssd前面。