z = np.maximum(z, 0.)
时间: 2023-02-05 10:38:02 浏览: 50
z = np.maximum(z, 0.) 这行代码中的 np.maximum 函数会对 z 中的每一个元素取其与 0 之间的最大值。例如,如果 z 中有一个元素是 -1,那么 np.maximum(z, 0.) 将会将这个元素变为 0。
这个操作常常被称为 “ReLU 激活”,因为它是一种常用的深度学习激活函数,名为 Rectified Linear Unit (ReLU)。ReLU 将所有小于等于 0 的元素转换为 0,而其它元素保持不变。
简而言之,这行代码的作用是将 z 中的所有小于等于 0 的元素变为 0。
相关问题
z = np.maximum(x, y)
z = np.maximum(x, y) 表示将数组 x 和 y 中对应位置的元素作比较,取出较大的元素放到新数组 z 中,即:
如果 x[i] > y[i],则 z[i] = x[i]
如果 x[i] ≤ y[i],则 z[i] = y[i]
例如:
x = [1, 2, 3]
y = [4, 5, 6]
z = np.maximum(x, y)
则 z 的值为 [4, 5, 6]。
from bm3d import bm3d_rgb from experiment_funcs1 import get_experiment_noise, get_psnr, get_cropped_psnr from PIL import Image import argparse import os import torch import numpy as np from torchvision.utils import save_image def main(): imagename = './test_image1/(1271).jpg' save_dir = 'test_result' save_path = 'noise' y = np.array(Image.open(imagename)) / 255 noise_type = 'g3' noise_var = 0.02 seed = 0 noise, psd, kernel = get_experiment_noise(noise_type, noise_var, seed, y.shape) z = np.atleast_3d(y) + np.atleast_3d(noise) y_est = bm3d_rgb(z, psd) psnr = get_psnr(y, y_est) print("PSNR:", psnr) y_est = np.minimum(np.maximum(y_est, 0), 1) z_rang = np.minimum(np.maximum(z, 0), 1) z_rang = torch.from_numpy(np.transpose(z_rang, (2, 0, 1))).float() y_est = torch.from_numpy(np.transpose(y_est, (2, 0, 1))).float() denoise_img_path = os.path.join(save_dir, 'denoised.jpg') save_image(y_est, denoise_img_path) noise_img_path = os.path.join(save_path, 'noise.jpg') save_image(z_rang, noise_img_path) if __name__ == '__main__': main()改为对灰度图处理
可以将代码中的`bm3d_rgb`函数改为`bm3d`函数,同时将读入图像的方式改为读入灰度图像即可。具体代码如下:
```
from bm3d import bm3d
from experiment_funcs1 import get_experiment_noise, get_psnr, get_cropped_psnr
from PIL import Image
import argparse
import os
import torch
import numpy as np
from torchvision.utils import save_image
def main():
imagename = './test_image1/(1271).jpg'
save_dir = 'test_result'
save_path = 'noise'
y = np.array(Image.open(imagename).convert('L')) / 255
noise_type = 'g3'
noise_var = 0.02
seed = 0
noise, psd, kernel = get_experiment_noise(noise_type, noise_var, seed, y.shape)
z = y + noise
y_est = bm3d(z, psd)
psnr = get_psnr(y, y_est)
print("PSNR:", psnr)
y_est = np.minimum(np.maximum(y_est, 0), 1)
z_rang = np.minimum(np.maximum(z, 0), 1)
z_rang = torch.from_numpy(z_rang).unsqueeze(0).float()
y_est = torch.from_numpy(y_est).unsqueeze(0).float()
denoise_img_path = os.path.join(save_dir, 'denoised.jpg')
save_image(y_est, denoise_img_path)
noise_img_path = os.path.join(save_path, 'noise.jpg')
save_image(z_rang, noise_img_path)
if __name__ == '__main__':
main()
```