全流程点云机器学习（二）使用PaddlePaddle进行PointNet的机器学习训练和评估

前言

这不是高支模项目需要嘛，他们用传统算法切那个横杆竖杆流程复杂耗时很长，所以想能不能用机器学习完成这些工作，所以我就来整这个工作了。

基于上文的数据集切分，现在来对切分好的数据来进行正式的训练。

本系列文章所用的核心骨干网络代码主要来自点云处理：实现PointNet点云分割

原文的代码有点问题，这里做了一点修改，主要应用了paddlepaddle进行的pointNet进行分割任务。

流程

这里用的PointNet网络由于使用了全连接层，所以输入必须要抽稀出结果，故而流程如下：

读取原始点云和标签
随机对原始点云和标签进行采样
进行数据集划分
创建模型
进行训练
保存模型
对象评估

具体内容

1.依赖

import os
import tqdm
import random
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
import  warnings
warnings.filterwarnings("ignore", module="matplotlib")    
from mpl_toolkits.mplot3d import Axes3D
# paddle相关库
import paddle
from paddle.io import Dataset
import paddle.nn.functional as F
from paddle.nn import Conv2D, MaxPool2D, Linear, BatchNorm, Dropout, ReLU, Softmax, Sequential

2.点云的可视化

def visualize_data(point_cloud, label, title):COLORS = ['b', 'y', 'r', 'g', 'pink']label_map = ['none', 'Support'] df = pd.DataFrame(data={"x": point_cloud[:, 0],"y": point_cloud[:, 1],"z": point_cloud[:, 2],"label": label,})fig = plt.figure(figsize=(15, 10))ax = plt.axes(projection="3d")ax.scatter(df["x"], df["y"], df["z"])for i in range(label.min(), label.max()+1):c_df = df[df['label'] == i]ax.scatter(c_df["x"], c_df["y"], c_df["z"], label=label_map[i], alpha=0.5, c=COLORS[i])ax.legend()plt.title(title)plt.show()input()

3.点云抽稀和数据集

data_path = 'J:\\output\\Data'
label_path = 'J:\\output\\Label'
# 采样点
NUM_SAMPLE_POINTS = 1024 
# 存储点云与label
point_clouds = []
point_clouds_labels = []file_list = os.listdir(data_path)
for file_name in tqdm.tqdm(file_list):# 获取label和data的地址label_name = file_name.replace('.pts', '.seg')point_cloud_file_path = os.path.join(data_path, file_name)label_file_path = os.path.join(label_path, label_name)# 读取label和datapoint_cloud = np.loadtxt(point_cloud_file_path)label = np.loadtxt(label_file_path).astype('int')# 如果本身的点少于需要采样的点，则直接去除if len(point_cloud) < NUM_SAMPLE_POINTS:continue# 采样num_points = len(point_cloud)# 确定随机采样的indexsampled_indices = random.sample(list(range(num_points)), NUM_SAMPLE_POINTS)# 点云采样sampled_point_cloud = np.array([point_cloud[i] for i in sampled_indices])# label采样sampled_label_cloud = np.array([label[i] for i in sampled_indices])# 正则化norm_point_cloud = sampled_point_cloud - np.mean(sampled_point_cloud, axis=0)norm_point_cloud /= np.max(np.linalg.norm(norm_point_cloud, axis=1))# 存储point_clouds.append(norm_point_cloud)point_clouds_labels.append(sampled_label_cloud)class MyDataset(Dataset):def __init__(self, data, label):super(MyDataset, self).__init__()self.data = dataself.label = labeldef __getitem__(self, index):data = self.data[index]label = self.label[index]data = np.reshape(data, (1, 1024, 3))return data, labeldef __len__(self):return len(self.data)

4. 进行数据集的划分

# 数据集划分
VAL_SPLIT = 0.2
split_index = int(len(point_clouds) * (1 - VAL_SPLIT))
train_point_clouds = point_clouds[:split_index]
train_label_cloud = point_clouds_labels[:split_index]
print(train_label_cloud)
total_training_examples = len(train_point_clouds)
val_point_clouds = point_clouds[split_index:]
val_label_cloud = point_clouds_labels[split_index:]
print("Num train point clouds:", len(train_point_clouds))
print("Num train point cloud labels:", len(train_label_cloud))
print("Num val point clouds:", len(val_point_clouds))
print("Num val point cloud labels:", len(val_label_cloud))# 测试定义的数据集
train_dataset = MyDataset(train_point_clouds, train_label_cloud)
val_dataset = MyDataset(val_point_clouds, val_label_cloud)print('=============custom dataset test=============')
for data, label in train_dataset:print('data shape:{} \nlabel shape:{}'.format(data.shape, label.shape))break# Batch_size 大小
BATCH_SIZE = 64
# # 数据加载
train_loader = paddle.io.DataLoader(train_dataset, batch_size=BATCH_SIZE, shuffle=True)
val_loader = paddle.io.DataLoader(val_dataset, batch_size=BATCH_SIZE, shuffle=False)

5. 创建PointNet网络

class PointNet(paddle.nn.Layer):def __init__(self, name_scope='PointNet_', num_classes=4, num_point=1024):super(PointNet, self).__init__()self.num_point = num_pointself.input_transform_net = Sequential(Conv2D(1, 64, (1, 3)),BatchNorm(64),ReLU(),Conv2D(64, 128, (1, 1)),BatchNorm(128),ReLU(),Conv2D(128, 1024, (1, 1)),BatchNorm(1024),ReLU(),MaxPool2D((num_point, 1)))self.input_fc = Sequential(Linear(1024, 512),ReLU(),Linear(512, 256),ReLU(),Linear(256, 9, weight_attr=paddle.framework.ParamAttr(initializer=paddle.nn.initializer.Assign(paddle.zeros((256, 9)))),bias_attr=paddle.framework.ParamAttr(initializer=paddle.nn.initializer.Assign(paddle.reshape(paddle.eye(3), [-1])))))self.mlp_1 = Sequential(Conv2D(1, 64, (1, 3)),BatchNorm(64),ReLU(),Conv2D(64, 64,(1, 1)),BatchNorm(64),ReLU(),)self.feature_transform_net = Sequential(Conv2D(64, 64, (1, 1)),BatchNorm(64),ReLU(),Conv2D(64, 128, (1, 1)),BatchNorm(128),ReLU(),Conv2D(128, 1024, (1, 1)),BatchNorm(1024),ReLU(),MaxPool2D((num_point, 1)))self.feature_fc = Sequential(Linear(1024, 512),ReLU(),Linear(512, 256),ReLU(),Linear(256, 64*64))self.mlp_2 = Sequential(Conv2D(64, 64, (1, 1)),BatchNorm(64),ReLU(),Conv2D(64, 128,(1, 1)),BatchNorm(128),ReLU(),Conv2D(128, 1024,(1, 1)),BatchNorm(1024),ReLU(),)self.seg_net = Sequential(Conv2D(1088, 512, (1, 1)),BatchNorm(512),ReLU(),Conv2D(512, 256, (1, 1)),BatchNorm(256),ReLU(),Conv2D(256, 128, (1, 1)),BatchNorm(128),ReLU(),Conv2D(128, 128, (1, 1)),BatchNorm(128),ReLU(),Conv2D(128, num_classes, (1, 1)),Softmax(axis=1))def forward(self, inputs):batchsize = inputs.shape[0]t_net = self.input_transform_net(inputs)t_net = paddle.squeeze(t_net)t_net = self.input_fc(t_net)t_net = paddle.reshape(t_net, [batchsize, 3, 3])x = paddle.reshape(inputs, shape=(batchsize, 1024, 3))x = paddle.matmul(x, t_net)x = paddle.unsqueeze(x, axis=1)x = self.mlp_1(x)t_net = self.feature_transform_net(x)t_net = paddle.squeeze(t_net)t_net = self.feature_fc(t_net)t_net = paddle.reshape(t_net, [batchsize, 64, 64])x = paddle.reshape(x, shape=(batchsize, 64, 1024))x = paddle.transpose(x, (0, 2, 1))x = paddle.matmul(x, t_net)x = paddle.transpose(x, (0, 2, 1))x = paddle.unsqueeze(x, axis=-1)point_feat = xx = self.mlp_2(x)x = paddle.max(x, axis=2)global_feat_expand = paddle.tile(paddle.unsqueeze(x, axis=1), [1, self.num_point, 1, 1])        x = paddle.concat([point_feat, global_feat_expand], axis=1)x = self.seg_net(x)x = paddle.squeeze(x, axis=-1)x = paddle.transpose(x, (0, 2, 1))return x# 创建模型
model = PointNet()
model.train()
# 优化器定义
optim = paddle.optimizer.Adam(parameters=model.parameters(), weight_decay=0.001)
# 损失函数定义
loss_fn = paddle.nn.CrossEntropyLoss()
# 评价指标定义
m = paddle.metric.Accuracy()

6. 训练模型

# 训练轮数
epoch_num = 50
# 每多少个epoch保存
save_interval = 2
# 每多少个epoch验证
val_interval = 2
best_acc = 0
# 模型保存地址
output_dir = './output'
if not os.path.exists(output_dir):os.makedirs(output_dir)
# 训练过程
plot_acc = []
plot_loss = []
for epoch in range(epoch_num):total_loss = 0for batch_id, data in enumerate(train_loader()):inputs = paddle.to_tensor(data[0], dtype='float32')labels = paddle.to_tensor(data[1], dtype='int64')print(data[1])print(labels)predicts = model(inputs)# 计算损失和反向传播loss = loss_fn(predicts, labels)if loss.ndim == 0:total_loss += loss.numpy()  # 零维数组，直接取值else:total_loss += loss.numpy()[0]  # 非零维数组，取第一个元素loss.backward()# 计算accpredicts = paddle.reshape(predicts, (predicts.shape[0]*predicts.shape[1], -1))labels = paddle.reshape(labels, (labels.shape[0]*labels.shape[1], 1))correct = m.compute(predicts, labels)m.update(correct)# 优化器更新optim.step()optim.clear_grad()avg_loss = total_loss/batch_idplot_loss.append(avg_loss)print("epoch: {}/{}, loss is: {}, acc is:{}".format(epoch, epoch_num, avg_loss, m.accumulate()))m.reset()# 保存if epoch % save_interval == 0:model_name = str(epoch)paddle.save(model.state_dict(), './output/PointNet_{}.pdparams'.format(model_name))paddle.save(optim.state_dict(), './output/PointNet_{}.pdopt'.format(model_name))# 训练中途验证if epoch % val_interval == 0:model.eval()for batch_id, data in enumerate(val_loader()): inputs = paddle.to_tensor(data[0], dtype='float32')labels = paddle.to_tensor(data[1], dtype='int64')predicts = model(inputs)predicts = paddle.reshape(predicts, (predicts.shape[0]*predicts.shape[1], -1))labels = paddle.reshape(labels, (labels.shape[0]*labels.shape[1], 1))correct = m.compute(predicts, labels)m.update(correct)val_acc = m.accumulate()plot_acc.append(val_acc)if val_acc > best_acc:best_acc = val_accprint("===================================val===========================================")print('val best epoch in:{}, best acc:{}'.format(epoch, best_acc))print("===================================train===========================================")paddle.save(model.state_dict(), './output/best_model.pdparams')paddle.save(optim.state_dict(), './output/best_model.pdopt')m.reset()model.train()

7.尝试对点云进行预测

ckpt_path = 'output/best_model.pdparams'
para_state_dict = paddle.load(ckpt_path)
# 加载网络和参数
model = PointNet()
model.set_state_dict(para_state_dict)
model.eval()
# 加载数据集
point_cloud = point_clouds[0]
show_point_cloud = point_cloud
point_cloud = paddle.to_tensor(np.reshape(point_cloud, (1, 1, 1024, 3)), dtype='float32')
label = point_clouds_labels[0]
# 前向推理
preds = model(point_cloud)
show_pred = paddle.argmax(preds, axis=-1).numpy() + 1visualize_data(show_point_cloud, show_pred[0], 'pred')
visualize_data(show_point_cloud, label, 'label')

全流程代码

import os
import tqdm
import random
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
import  warnings
warnings.filterwarnings("ignore", module="matplotlib")    
from mpl_toolkits.mplot3d import Axes3D# paddle相关库
import paddle
from paddle.io import Dataset
import paddle.nn.functional as F
from paddle.nn import Conv2D, MaxPool2D, Linear, BatchNorm, Dropout, ReLU, Softmax, Sequential# 可视化使用的颜色和对应label的名字def visualize_data(point_cloud, label, title):COLORS = ['b', 'y', 'r', 'g', 'pink']label_map = ['none', 'Support'] df = pd.DataFrame(data={"x": point_cloud[:, 0],"y": point_cloud[:, 1],"z": point_cloud[:, 2],"label": label,})fig = plt.figure(figsize=(15, 10))ax = plt.axes(projection="3d")ax.scatter(df["x"], df["y"], df["z"])for i in range(label.min(), label.max()+1):c_df = df[df['label'] == i]ax.scatter(c_df["x"], c_df["y"], c_df["z"], label=label_map[i], alpha=0.5, c=COLORS[i])ax.legend()plt.title(title)plt.show()input()data_path = 'J:\\output\\Data'
label_path = 'J:\\output\\Label'
# 采样点
NUM_SAMPLE_POINTS = 1024 
# 存储点云与label
point_clouds = []
point_clouds_labels = []file_list = os.listdir(data_path)
for file_name in tqdm.tqdm(file_list):# 获取label和data的地址label_name = file_name.replace('.pts', '.seg')point_cloud_file_path = os.path.join(data_path, file_name)label_file_path = os.path.join(label_path, label_name)# 读取label和datapoint_cloud = np.loadtxt(point_cloud_file_path)label = np.loadtxt(label_file_path).astype('int')# 如果本身的点少于需要采样的点，则直接去除if len(point_cloud) < NUM_SAMPLE_POINTS:continue# 采样num_points = len(point_cloud)# 确定随机采样的indexsampled_indices = random.sample(list(range(num_points)), NUM_SAMPLE_POINTS)# 点云采样sampled_point_cloud = np.array([point_cloud[i] for i in sampled_indices])# label采样sampled_label_cloud = np.array([label[i] for i in sampled_indices])# 正则化norm_point_cloud = sampled_point_cloud - np.mean(sampled_point_cloud, axis=0)norm_point_cloud /= np.max(np.linalg.norm(norm_point_cloud, axis=1))# 存储point_clouds.append(norm_point_cloud)point_clouds_labels.append(sampled_label_cloud)#visualize_data(point_clouds[0], point_clouds_labels[0], 'label')class MyDataset(Dataset):def __init__(self, data, label):super(MyDataset, self).__init__()self.data = dataself.label = labeldef __getitem__(self, index):data = self.data[index]label = self.label[index]data = np.reshape(data, (1, 1024, 3))return data, labeldef __len__(self):return len(self.data)# 数据集划分
VAL_SPLIT = 0.2
split_index = int(len(point_clouds) * (1 - VAL_SPLIT))
train_point_clouds = point_clouds[:split_index]
train_label_cloud = point_clouds_labels[:split_index]
print(train_label_cloud)
total_training_examples = len(train_point_clouds)
val_point_clouds = point_clouds[split_index:]
val_label_cloud = point_clouds_labels[split_index:]
print("Num train point clouds:", len(train_point_clouds))
print("Num train point cloud labels:", len(train_label_cloud))
print("Num val point clouds:", len(val_point_clouds))
print("Num val point cloud labels:", len(val_label_cloud))# 测试定义的数据集
train_dataset = MyDataset(train_point_clouds, train_label_cloud)
val_dataset = MyDataset(val_point_clouds, val_label_cloud)print('=============custom dataset test=============')
for data, label in train_dataset:print('data shape:{} \nlabel shape:{}'.format(data.shape, label.shape))break# Batch_size 大小
BATCH_SIZE = 64
# # 数据加载
train_loader = paddle.io.DataLoader(train_dataset, batch_size=BATCH_SIZE, shuffle=True)
val_loader = paddle.io.DataLoader(val_dataset, batch_size=BATCH_SIZE, shuffle=False)class PointNet(paddle.nn.Layer):def __init__(self, name_scope='PointNet_', num_classes=4, num_point=1024):super(PointNet, self).__init__()self.num_point = num_pointself.input_transform_net = Sequential(Conv2D(1, 64, (1, 3)),BatchNorm(64),ReLU(),Conv2D(64, 128, (1, 1)),BatchNorm(128),ReLU(),Conv2D(128, 1024, (1, 1)),BatchNorm(1024),ReLU(),MaxPool2D((num_point, 1)))self.input_fc = Sequential(Linear(1024, 512),ReLU(),Linear(512, 256),ReLU(),Linear(256, 9, weight_attr=paddle.framework.ParamAttr(initializer=paddle.nn.initializer.Assign(paddle.zeros((256, 9)))),bias_attr=paddle.framework.ParamAttr(initializer=paddle.nn.initializer.Assign(paddle.reshape(paddle.eye(3), [-1])))))self.mlp_1 = Sequential(Conv2D(1, 64, (1, 3)),BatchNorm(64),ReLU(),Conv2D(64, 64,(1, 1)),BatchNorm(64),ReLU(),)self.feature_transform_net = Sequential(Conv2D(64, 64, (1, 1)),BatchNorm(64),ReLU(),Conv2D(64, 128, (1, 1)),BatchNorm(128),ReLU(),Conv2D(128, 1024, (1, 1)),BatchNorm(1024),ReLU(),MaxPool2D((num_point, 1)))self.feature_fc = Sequential(Linear(1024, 512),ReLU(),Linear(512, 256),ReLU(),Linear(256, 64*64))self.mlp_2 = Sequential(Conv2D(64, 64, (1, 1)),BatchNorm(64),ReLU(),Conv2D(64, 128,(1, 1)),BatchNorm(128),ReLU(),Conv2D(128, 1024,(1, 1)),BatchNorm(1024),ReLU(),)self.seg_net = Sequential(Conv2D(1088, 512, (1, 1)),BatchNorm(512),ReLU(),Conv2D(512, 256, (1, 1)),BatchNorm(256),ReLU(),Conv2D(256, 128, (1, 1)),BatchNorm(128),ReLU(),Conv2D(128, 128, (1, 1)),BatchNorm(128),ReLU(),Conv2D(128, num_classes, (1, 1)),Softmax(axis=1))def forward(self, inputs):batchsize = inputs.shape[0]t_net = self.input_transform_net(inputs)t_net = paddle.squeeze(t_net)t_net = self.input_fc(t_net)t_net = paddle.reshape(t_net, [batchsize, 3, 3])x = paddle.reshape(inputs, shape=(batchsize, 1024, 3))x = paddle.matmul(x, t_net)x = paddle.unsqueeze(x, axis=1)x = self.mlp_1(x)t_net = self.feature_transform_net(x)t_net = paddle.squeeze(t_net)t_net = self.feature_fc(t_net)t_net = paddle.reshape(t_net, [batchsize, 64, 64])x = paddle.reshape(x, shape=(batchsize, 64, 1024))x = paddle.transpose(x, (0, 2, 1))x = paddle.matmul(x, t_net)x = paddle.transpose(x, (0, 2, 1))x = paddle.unsqueeze(x, axis=-1)point_feat = xx = self.mlp_2(x)x = paddle.max(x, axis=2)global_feat_expand = paddle.tile(paddle.unsqueeze(x, axis=1), [1, self.num_point, 1, 1])        x = paddle.concat([point_feat, global_feat_expand], axis=1)x = self.seg_net(x)x = paddle.squeeze(x, axis=-1)x = paddle.transpose(x, (0, 2, 1))return x# 创建模型
model = PointNet()
model.train()
# 优化器定义
optim = paddle.optimizer.Adam(parameters=model.parameters(), weight_decay=0.001)
# 损失函数定义
loss_fn = paddle.nn.CrossEntropyLoss()
# 评价指标定义
m = paddle.metric.Accuracy()
# 训练轮数
epoch_num = 50
# 每多少个epoch保存
save_interval = 2
# 每多少个epoch验证
val_interval = 2
best_acc = 0
# 模型保存地址
output_dir = './output'
if not os.path.exists(output_dir):os.makedirs(output_dir)
# 训练过程
plot_acc = []
plot_loss = []
for epoch in range(epoch_num):total_loss = 0for batch_id, data in enumerate(train_loader()):inputs = paddle.to_tensor(data[0], dtype='float32')labels = paddle.to_tensor(data[1], dtype='int64')print(data[1])print(labels)predicts = model(inputs)# 计算损失和反向传播loss = loss_fn(predicts, labels)if loss.ndim == 0:total_loss += loss.numpy()  # 零维数组，直接取值else:total_loss += loss.numpy()[0]  # 非零维数组，取第一个元素loss.backward()# 计算accpredicts = paddle.reshape(predicts, (predicts.shape[0]*predicts.shape[1], -1))labels = paddle.reshape(labels, (labels.shape[0]*labels.shape[1], 1))correct = m.compute(predicts, labels)m.update(correct)# 优化器更新optim.step()optim.clear_grad()avg_loss = total_loss/batch_idplot_loss.append(avg_loss)print("epoch: {}/{}, loss is: {}, acc is:{}".format(epoch, epoch_num, avg_loss, m.accumulate()))m.reset()# 保存if epoch % save_interval == 0:model_name = str(epoch)paddle.save(model.state_dict(), './output/PointNet_{}.pdparams'.format(model_name))paddle.save(optim.state_dict(), './output/PointNet_{}.pdopt'.format(model_name))# 训练中途验证if epoch % val_interval == 0:model.eval()for batch_id, data in enumerate(val_loader()): inputs = paddle.to_tensor(data[0], dtype='float32')labels = paddle.to_tensor(data[1], dtype='int64')predicts = model(inputs)predicts = paddle.reshape(predicts, (predicts.shape[0]*predicts.shape[1], -1))labels = paddle.reshape(labels, (labels.shape[0]*labels.shape[1], 1))correct = m.compute(predicts, labels)m.update(correct)val_acc = m.accumulate()plot_acc.append(val_acc)if val_acc > best_acc:best_acc = val_accprint("===================================val===========================================")print('val best epoch in:{}, best acc:{}'.format(epoch, best_acc))print("===================================train===========================================")paddle.save(model.state_dict(), './output/best_model.pdparams')paddle.save(optim.state_dict(), './output/best_model.pdopt')m.reset()model.train()ckpt_path = 'output/best_model.pdparams'
para_state_dict = paddle.load(ckpt_path)
# 加载网络和参数
model = PointNet()
model.set_state_dict(para_state_dict)
model.eval()
# 加载数据集
point_cloud = point_clouds[0]
show_point_cloud = point_cloud
point_cloud = paddle.to_tensor(np.reshape(point_cloud, (1, 1, 1024, 3)), dtype='float32')
label = point_clouds_labels[0]
# 前向推理
preds = model(point_cloud)
show_pred = paddle.argmax(preds, axis=-1).numpy() + 1visualize_data(show_point_cloud, show_pred[0], 'pred')
visualize_data(show_point_cloud, label, 'label')