histogram_quantization.py

import cv2
import matplotlib.pyplot as plt

# Read grayscale image
img = cv2.imread('image.jpg', cv2.IMREAD_GRAYSCALE)

if img is None:
    print("Error: image.jpg not found!")
    exit()

# Histogram Equalization
equalized_img = cv2.equalizeHist(img)

# Calculate histograms
hist_original = cv2.calcHist([img], [0], None, [256], [0, 256])
hist_equalized = cv2.calcHist([equalized_img], [0], None, [256], [0, 256])

# Plot results
plt.figure(figsize=(14, 8))

# Original image
plt.subplot(2, 2, 1)
plt.imshow(img, cmap='gray')
plt.title("Original Image")
plt.axis('off')

# Equalized image
plt.subplot(2, 2, 2)
plt.imshow(equalized_img, cmap='gray')
plt.title("Equalized Image")
plt.axis('off')

# Original histogram
plt.subplot(2, 2, 3)
plt.plot(hist_original)
plt.title("Original Histogram")

# Equalized histogram
plt.subplot(2, 2, 4)
plt.plot(hist_equalized)
plt.title("Equalized Histogram")

plt.tight_layout()
plt.show()