OpenCV Python Image Blending with Pyramids Tutorial: Seamless Image Fusion Guide

OpenCV Python – Image Blending with Pyramids

Image blending with pyramids is an advanced image processing technique used to combine two images smoothly without visible seams. Unlike simple blending, pyramid blending preserves details and creates natural transitions.

In OpenCV Python, this method uses Gaussian and Laplacian pyramids for high-quality image fusion.

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1. What is Pyramid Blending?

Pyramid blending is a technique that:

• Combines images at multiple resolutions
• Smoothly merges edges and textures
• Removes sharp boundaries between images

It is widely used in professional image editing.

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2. Import OpenCV and NumPy

import cv2
import numpy as np

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3. Read Images

img1 = cv2.imread("image1.jpg")
img2 = cv2.imread("image2.jpg")

img2 = cv2.resize(img2, (img1.shape[1], img1.shape[0]))

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4. Generate Gaussian Pyramids

G1 = img1.copy()
G2 = img2.copy()

gp1 = [G1]
gp2 = [G2]

for i in range(6):
    G1 = cv2.pyrDown(G1)
    G2 = cv2.pyrDown(G2)
    gp1.append(G1)
    gp2.append(G2)

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5. Generate Laplacian Pyramids

lp1 = [gp1[-1]]
lp2 = [gp2[-1]]

for i in range(5, 0, -1):
    GE1 = cv2.pyrUp(gp1[i])
    GE2 = cv2.pyrUp(gp2[i])

    L1 = cv2.subtract(gp1[i-1], GE1)
    L2 = cv2.subtract(gp2[i-1], GE2)

    lp1.append(L1)
    lp2.append(L2)

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6. Blend Pyramids

LS = []

for l1, l2 in zip(lp1, lp2):
    rows, cols, dpt = l1.shape
    ls = np.hstack((l1[:, 0:cols//2], l2[:, cols//2:]))
    LS.append(ls)

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7. Reconstruct Blended Image

ls_ = LS[0]

for i in range(1, 6):
    ls_ = cv2.pyrUp(ls_)
    ls_ = cv2.add(ls_, LS[i])

cv2.imshow("Pyramid Blending", ls_)
cv2.waitKey(0)
cv2.destroyAllWindows()

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8. Why Pyramid Blending is Important

Pyramid blending is used in:

• Panorama stitching
• Seamless image editing
• Face morphing
• AR/VR applications
• Professional photo editing

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9. Advantages of Pyramid Blending

• Smooth transitions between images
• No visible seams
• High-quality results
• Multi-scale image fusion

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10. Common Mistakes

❌ Images not same size

✔ Solution:

• Always resize images before blending

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❌ Too few pyramid levels

✔ Solution:

• Use 4–6 levels for best quality

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11. Conclusion

Image blending with pyramids in OpenCV Python is a powerful technique for creating seamless image fusion. It is widely used in professional image editing and computer vision applications.

Once you master this, you can move to advanced topics like image stitching and panorama creation.