niqe的python代码

以下是使用Python实现NIQE的代码：

import numpy as np
import cv2
import torch
from torch.autograd import Variable
from scipy import signal

def niqe(img):
    # 读取图像并转换为灰度图像
    img = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
    img = np.float32(img) / 255.0

    # 计算局部方差
    mu = signal.convolve2d(img, np.ones((8, 8)), mode='same', boundary='symm') / 64.0
    mu_sq = mu * mu
    sigma = np.sqrt(abs(signal.convolve2d(img * img, np.ones((8, 8)), mode='same', boundary='symm') / 64.0 - mu_sq))

    # 计算局部对比度
    structdis = cv2.getStructuringElement(cv2.MORPH_ELLIPSE, (7, 7))
    mu = cv2.morphologyEx(mu, cv2.MORPH_OPEN, structdis)
    sigma = cv2.morphologyEx(sigma, cv2.MORPH_OPEN, structdis)
    lpc = sigma / mu

    # 计算NIQE
    niqe_features = []
    niqe_features.append(np.mean(lpc))
    niqe_features.append(np.std(lpc))
    niqe_features.append(np.mean(sigma))
    niqe_features.append(np.std(sigma))

    niqe_features = np.array(niqe_features)
    niqe_features = np.reshape(niqe_features, (1, niqe_features.shape[0]))

    # 加载NIQE模型并计算NIQE分数
    model = torch.load('niqe/niqe_model.pth')
    niqe_features = Variable(torch.FloatTensor(niqe_features))
    niqe_score = model(niqe_features)

    return niqe_score.item()