ObjectDetectio-watermarking/tool/training_embedding.py

import torch.nn as nn
import torch
from torch.optim import SGD, Adam
import torch.nn.functional as F


def string2bin(s):
    binary_representation = ''.join(format(ord(x), '08b') for x in s)
    return [int(x) for x in binary_representation]


def bin2string(binary_string):
    return ''.join(chr(int(binary_string[i:i + 8], 2)) for i in range(0, len(binary_string), 8))


class Embedding():
    def __init__(self, model, code, key_path: str = None, l=1, train=True, device='cuda'):
        """
        初始化白盒水印编码器
        :param model: 模型定义
        :param code: 密钥,字符串格式
        :param key_path: 投影矩阵权重文件保存路径
        :param l: 水印编码器loss权重
        :param train: 是否是训练环境，默认为True
        :param device: 运行设备，默认为cuda
        """
        super(Embedding, self).__init__()

        self.p = self.get_parameters(model)

        self.key_path = key_path if key_path is not None else './key.pt'

        self.device = device

        # self.p = parameters

        # self.w = nn.Parameter(w, requires_grad=True)

        # the flatten mean parameters
        # w = torch.mean(self.p, dim=1).reshape(-1)
        w = self.flatten_parameters(self.p)
        self.l = l

        self.w_init = w.clone().detach()

        print('Size of embedding parameters:', w.shape)

        self.opt = Adam(self.p, lr=0.001)
        self.distribution_ignore = ['train_acc']
        self.code = torch.tensor(string2bin(
            code), dtype=torch.float).to(self.device)  # the embedding code
        self.code_len = self.code.shape[0]
        print(f'Code:{self.code} code length:{self.code_len}')

        # 判断是否为训练环境，如果是测试环境，直接加载投影矩阵，训练环境随机生成X矩阵，并保存至key_path中
        if not train:
            self.load_matrix(key_path)
        else:
            self.X_random = torch.randn(
                (self.code_len, self.w_init.shape[0])).to(self.device)
            self.save_matrix()

    def save_matrix(self):
        torch.save(self.X_random, self.key_path)

    def load_matrix(self, path):
        self.X_random = torch.load(path).to(self.device)

    def get_parameters(self, model):
        target = model.get_encode_layers()
        print(f'Embedding target:{target}')
        # parameters = target.weight
        parameters = [x.weight for x in target]
        return parameters

    # add penalty value to loss
    def add_penalty(self, loss):
        # print(f'original loss:{loss} ')
        w = self.flatten_parameters(self.p)
        prob = self.get_prob(self.X_random, w)
        penalty = self.loss_fun(
            prob, self.code)
        loss += self.l * penalty
        # print(f'penalty loss:{loss} ')
        return loss

    def flatten_parameters(self, parameters):
        parameter = torch.cat([torch.mean(x, dim=3).reshape(-1)
                               for x in parameters])
        return parameter

    def loss_fun(self, x, y):
        penalty = F.binary_cross_entropy(x, y)
        return penalty

    def decode(self, X, w):
        prob = self.get_prob(X, w)
        return torch.where(prob > 0.5, 1, 0)

    def get_prob(self, X, w):
        mm = torch.mm(self.X_random, w.reshape((w.shape[0], 1)))
        return F.sigmoid(mm).flatten()

    def test(self):
        w = self.flatten_parameters(self.p)
        decode = self.decode(self.X_random, w)
        print(decode.shape)
        code_string = ''.join([str(x) for x in decode.tolist()])
        code_string = bin2string(code_string)
        print('decoded code:', code_string)
        return code_string