Python/analysis/compression_analysis/psnr.py
Rafael García Cuéllar beafe3656f Re-design psnr.py code and change image names (#592)
* Change some Image File names & re-code the psnr algorithm (conserving both methods). Also Added new example.

* Selected psnr method and reformat some code from arithmetic_analysis
2018-11-05 18:19:08 +01:00

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1.0 KiB
Python

"""
Peak signal-to-noise ratio - PSNR - https://en.wikipedia.org/wiki/Peak_signal-to-noise_ratio
Soruce: https://tutorials.techonical.com/how-to-calculate-psnr-value-of-two-images-using-python/
"""
import math
import cv2
import numpy as np
def psnr(original, contrast):
mse = np.mean((original - contrast) ** 2)
if mse == 0:
return 100
PIXEL_MAX = 255.0
PSNR = 20 * math.log10(PIXEL_MAX / math.sqrt(mse))
return PSNR
def main():
# Loading images (original image and compressed image)
original = cv2.imread('original_image.png')
contrast = cv2.imread('compressed_image.png', 1)
original2 = cv2.imread('PSNR-example-base.png')
contrast2 = cv2.imread('PSNR-example-comp-10.jpg', 1)
# Value expected: 29.73dB
print("-- First Test --")
print(f"PSNR value is {psnr(original, contrast)} dB")
# # Value expected: 31.53dB (Wikipedia Example)
print("\n-- Second Test --")
print(f"PSNR value is {psnr(original2, contrast2)} dB")
if __name__ == '__main__':
main()