人脸识别系统：基于MindSpore的ResNet模型实时识别

本项目使用MindSpore框架构建了一个人脸识别系统，利用ResNet模型进行实时人脸识别。系统包含模型训练和识别两部分，支持加载预训练模型并识别摄像头画面中的人脸，并显示识别结果。

一、模型训练

import numpy as np
import mindspore.dataset as ds
import os
import cv2
import mindspore
import mindspore.nn as nn
from mindspore import Tensor
from mindspore.common.initializer import Normal
from mindspore import context
from mindspore.train.callback import ModelCheckpoint, CheckpointConfig, LossMonitor, TimeMonitor
from mindspore.train import Model
from mindspore.nn.metrics import Accuracy
from mindspore.ops.operations import TensorAdd
from scipy.integrate._ivp.radau import P
from mindspore import Model # 承载网络结构
from mindspore.nn.metrics import Accuracy # 测试模型用

np.random.seed(58)


class BasicBlock(nn.Cell):
    def __init__(self, in_channels, out_channels, stride=1, downsample=None):
        super(BasicBlock, self).__init__()
        self.conv1 = nn.Conv2d(in_channels, out_channels, kernel_size=3, stride=stride, padding=1, pad_mode='pad',has_bias=False)
        self.bn1 = nn.BatchNorm2d(out_channels)
        self.relu = nn.ReLU()
        self.conv2 = nn.Conv2d(out_channels, out_channels, kernel_size=3, stride=1, padding=1, pad_mode='pad', has_bias=False)
        self.bn2 = nn.BatchNorm2d(out_channels)
        self.downsample = downsample
        self.add = TensorAdd()

    def construct(self, x):
        identity = x

        out = self.conv1(x)
        out = self.bn1(out)
        out = self.relu(out)

        out = self.conv2(out)
        out = self.bn2(out)

        if self.downsample is not None:
            identity = self.downsample(x)

        out = self.add(out, identity)
        out = self.relu(out)

        return out

class ResNet(nn.Cell):
    def __init__(self, block, layers, num_classes=10):
        super(ResNet, self).__init__()
        self.in_channels = 64

        self.conv1 = nn.Conv2d(3, 64, kernel_size=7, stride=2, padding=3, pad_mode='pad', has_bias=False)
        self.bn1 = nn.BatchNorm2d(64)
        self.relu = nn.ReLU()
        self.maxpool = nn.MaxPool2d(kernel_size=3, stride=2, pad_mode='same')
        self.layer1 = self.make_layer(block, 64, layers[0])
        self.layer2 = self.make_layer(block, 128, layers[1], stride=2)
        self.layer3 = self.make_layer(block, 256, layers[2], stride=2)
        self.layer4 = self.make_layer(block, 512, layers[3], stride=2)
        self.avgpool = nn.AvgPool2d(kernel_size=7, stride=1)
        self.flatten = nn.Flatten()
        self.fc = nn.Dense(512, num_classes)

    def make_layer(self, block, out_channels, blocks, stride=1):
        downsample = None
        if stride != 1 or self.in_channels != out_channels:
            downsample = nn.SequentialCell([
                nn.Conv2d(self.in_channels, out_channels, kernel_size=1, stride=stride, has_bias=False),
                nn.BatchNorm2d(out_channels)
            ])

        layers = []
        layers.append(block(self.in_channels, out_channels, stride, downsample))
        self.in_channels = out_channels
        for _ in range(1, blocks):
            layers.append(block(out_channels, out_channels))

        return nn.SequentialCell(layers)

    def construct(self, x):
        x = self.conv1(x)
        x = self.bn1(x)
        x = self.relu(x)
        x = self.maxpool(x)

        x = self.layer1(x)
        x = self.layer2(x)
        x = self.layer3(x)
        x = self.layer4(x)

        x = self.avgpool(x)
        x = self.flatten(x)
        x = self.fc(x)

        return x


class TrainDatasetGenerator:
    def __init__(self, file_path):
        self.file_path = file_path
        self.img_names = os.listdir(file_path)

    def __getitem__(self, index):
        data = cv2.imread(os.path.join(self.file_path, self.img_names[index]))
        label = self.img_names[index].split('_')[0]
        label = int(label)
        data = cv2.cvtColor(data, cv2.COLOR_BGR2RGB)
        data = cv2.resize(data, (224, 224))
        data = data.transpose().astype(np.float32) / 255.
        return data, label

    def __len__(self):
        return len(self.img_names)


def train_resnet():
    context.set_context(mode=context.GRAPH_MODE, device_target='CPU')
    train_dataset_generator = TrainDatasetGenerator('D:/pythonProject7/train1')
    ds_train = ds.GeneratorDataset(train_dataset_generator, ['data', 'label'], shuffle=True)
    ds_train = ds_train.shuffle(buffer_size=10)
    ds_train = ds_train.batch(batch_size=4, drop_remainder=True)
    valid_dataset_generator = TrainDatasetGenerator('D:/pythonProject7/test1')
    ds_valid = ds.GeneratorDataset(valid_dataset_generator, ['data', 'label'], shuffle=True)
    ds_valid = ds_valid.batch(batch_size=4, drop_remainder=True)
    network = ResNet(BasicBlock, [2, 2, 2, 2], num_classes=100)
    net_loss = nn.SoftmaxCrossEntropyWithLogits(sparse=True, reduction='mean')
    net_opt = nn.Momentum(network.trainable_params(), learning_rate=0.01, momentum=0.9)
    time_cb = TimeMonitor(data_size=ds_train.get_dataset_size())
    config_ck = CheckpointConfig(save_checkpoint_steps=10, keep_checkpoint_max=10)
    config_ckpt_path = 'D:/pythonProject7/ckpt/'
    ckpoint_cb = ModelCheckpoint(prefix='checkpoint_resnet', directory=config_ckpt_path, config=config_ck)

    model = Model(network, net_loss, net_opt, metrics={'Accuracy': Accuracy()})
    epoch_size = 10
    print('============== Starting Training =============')
    model.train(epoch_size, ds_train, callbacks=[time_cb, ckpoint_cb, LossMonitor()])

    acc = model.eval(ds_valid)
    print('============== {} ============='.format(acc))
    epoch_size = 10
    print('============== Starting Training =============')
    model.train(epoch_size, ds_train, callbacks=[time_cb, ckpoint_cb, LossMonitor()])

    acc = model.eval(ds_valid)
    print('============== {} ============='.format(acc))
    epoch_size = 10
    print('============== Starting Training =============')
    model.train(epoch_size, ds_train, callbacks=[time_cb, ckpoint_cb, LossMonitor()])

    acc = model.eval(ds_valid)
    print('============== {} ============='.format(acc))

if __name__ == '__main__':
    train_resnet()

二、识别

import os
import cv2
import numpy as np
import mindspore
from mindspore import Tensor, load_checkpoint, load_param_into_net
from mindspore.dataset.vision import py_transforms
from mindspore.dataset.transforms.py_transforms import Compose
from PIL import Image
from main import ResNet, BasicBlock

# 加载标签
with open('label.txt') as f:
    labels = f.readlines()
labels = [l.strip() for l in labels]

# 加载人脸检测器
face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')

# 打开摄像头
cap = cv2.VideoCapture(0)


# 遍历ckpt文件夹中的所有ckpt文件
ckpt_dir = 'D:/pythonProject7/ckpt/'
ckpt_files = os.listdir(ckpt_dir)
ckpt_files = [f for f in ckpt_files if f.endswith('.ckpt')]
ckpt_files.sort(key=lambda x: os.path.getmtime(os.path.join(ckpt_dir, x)))

for ckpt_file in ckpt_files:
    # 加载模型的函数
    def load_model():
        network = ResNet(BasicBlock, [2, 2, 2, 2], num_classes=100)
        params = load_checkpoint(os.path.join(ckpt_dir, ckpt_file))
        load_param_into_net(network, params)
        return network

    # 加载模型
    network = load_model()

    while True:
        # 读取视频帧
        ret, frame = cap.read()

        # 转换为灰度图像
        gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

        # 检测人脸
        faces = face_cascade.detectMultiScale(gray, 1.3, 5)

        for (x, y, w, h) in faces:
            # 提取人脸图像
            face = gray[y:y + h, x:x + w]
            face = cv2.resize(face, (224, 224)).astype(np.float32)
            face = cv2.cvtColor(face, cv2.COLOR_GRAY2RGB)

            # 转换为Tensor类型，并进行归一化
            transform = Compose([
                py_transforms.ToTensor(),
                py_transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225])
            ])
            face = transform(face)

            # 转换为Tensor类型，并增加一个维度
            face = Tensor(face)
            #face = mindspore.ops.ExpandDims()(face, 0)

            # 预测人脸所属的类别
            output = network(face)
            prediction = np.argmax(output.asnumpy())

            # 在图像上标注人脸和类别
            cv2.rectangle(frame, (x, y), (x + w, y + h), (0, 255, 0), 2)
            cv2.putText(frame, labels[prediction], (x, y - 10), cv2.FONT_HERSHEY_SIMPLEX, 0.9, (0, 0, 255), 2)

        # 显示图像
        cv2.imshow('frame', frame)
        if cv2.waitKey(1) & 0xFF == ord('q'):
            break

    # 释放摄像头并关闭窗口
    cap.release()
    cv2.destroyAllWindows()

三、使用说明

准备训练数据集：将训练数据放置于D:/pythonProject7/train1文件夹中，每个文件夹代表一个类别，文件夹名称为该类别的标签，例如：0、1、2等。每个文件夹下存放对应类别的图片。
准备测试数据集：将测试数据放置于D:/pythonProject7/test1文件夹中，结构与训练数据集相同。
准备标签文件：创建一个名为label.txt的文件，将所有类别的标签名写入该文件，每行一个标签名，例如：

0
1
2
...

运行训练脚本：执行train_resnet()函数，训练模型并保存模型参数至D:/pythonProject7/ckpt文件夹中。
运行识别脚本：执行识别脚本，加载模型参数，识别摄像头画面中的人脸，并显示识别结果。

四、注意

训练数据集和测试数据集的图片应为224x224像素大小，并进行归一化处理。
模型训练和识别使用的环境需要安装MindSpore框架，以及相关依赖库。
文件路径应根据实际情况进行修改。
识别结果可能受多种因素影响，例如摄像头质量、光线条件、人脸姿态等。

五、进一步优化

可以尝试使用更多数据进行模型训练，以提高识别准确率。
可以尝试使用更复杂的模型结构，例如MobileNet、VGG等。
可以使用更先进的人脸检测算法，例如MTCNN。
可以将模型部署到其他平台，例如Android、iOS等。

本项目只是一个简单的入门教程，希望能够帮助您了解如何使用MindSpore框架构建人脸识别系统。如果您有任何问题，请随时提出。