psnr python代码
时间: 2023-11-08 18:01:16 浏览: 49
psnr python代码如下所示:
```python
import numpy as np
import math
def psnr(target, ref, scale):
# target: 目标图像
# ref: 参考图像
# scale: 尺寸大小
# 假设目标图像是RGB图像
target_data = np.array(target)
target_data = target_data[scale:-scale,scale:-scale]
ref_data = np.array(ref)
ref_data = ref_data[scale:-scale,scale:-scale]
diff = ref_data - target_data
diff = diff.flatten('C')
rmse = math.sqrt(np.mean(diff ** 2.))
return 20 * math.log10(1.0 / rmse)
```
相关问题
PSNR python代码
PSNR(Peak Signal-to-Noise Ratio)是一种用于衡量图像或视频质量的指标,可以通过计算原始图像与压缩/恢复后的图像之间的峰值信噪比来评估图像的失真程度。下面是一个简单的Python代码示例,用于计算两个图像之间的PSNR值:
```python
import cv2
import numpy as np
def calculate_psnr(original_image, compressed_image):
# 读取原始图像和压缩/恢复后的图像
img1 = cv2.imread(original_image)
img2 = cv2.imread(compressed_image)
# 将图像转换为灰度图像
gray_img1 = cv2.cvtColor(img1, cv2.COLOR_BGR2GRAY)
gray_img2 = cv2.cvtColor(img2, cv2.COLOR_BGR2GRAY)
# 计算MSE(均方误差)
mse = np.mean((gray_img1 - gray_img2) **2)
# 计算PSNR值
if mse == 0:
psnr = float('inf')
else:
max_pixel_value = 255.0
psnr = 20 * np.log10(max_pixel_value / np.sqrt(mse))
return psnr
# 示例用法
original_image_path = 'original_image.jpg'
compressed_image_path = 'compressed_image.jpg'
psnr_value = calculate_psnr(original_image_path, compressed_image_path)
print("PSNR value:", psnr_value)
```
请注意,上述代码使用了OpenCV库来读取和处理图像。在运行代码之前,请确保已经安装了OpenCV库。另外,需要将`original_image.jpg`和`compressed_image.jpg`替换为实际的图像文件路径。
psnr代码 python ycbcr
以下是一个计算图像 PSNR(峰值信噪比)的 Python 代码示例,使用 YCbCr 颜色空间:
```python
import cv2
import numpy as np
def calculate_psnr(img1, img2):
# Convert images to YCbCr color space
img1_yuv = cv2.cvtColor(img1, cv2.COLOR_BGR2YCR_CB)
img2_yuv = cv2.cvtColor(img2, cv2.COLOR_BGR2YCR_CB)
# Calculate MSE (Mean Squared Error)
mse = np.mean((img1_yuv - img2_yuv) ** 2)
# Calculate maximum pixel value
max_pixel = np.max(img1_yuv)
# Calculate PSNR
psnr = 20 * np.log10(max_pixel / np.sqrt(mse))
return psnr
# 读取两个图像
img1 = cv2.imread('image1.jpg')
img2 = cv2.imread('image2.jpg')
# 调用函数计算 PSNR
psnr_value = calculate_psnr(img1, img2)
print("PSNR:", psnr_value)
```
请确保图像文件 `image1.jpg` 和 `image2.jpg` 存在,或者根据你的需求修改文件名。这段代码使用 OpenCV 库进行图像处理和颜色转换,计算得到的 PSNR 值将被打印出来。