Kyle Xu

10/16/2014

Image Blending

•  Simple to Advanced Approaches –  Alpha Blending –  Image Feathering –  Pyramid Blending

•  Applications

•  Envision

Agenda

The simplest solution - Alpha Blending

Ioverlap = α x Ileft + (1 - α) x Iright

α = .2 α = .4 α = .6 α = .8

Center Pixels > Edge Pixels

A

At position A:

Pixel from the left Image - Close to the edge - Less contribution to the perception

Center Pixels > Edge Pixels

A

At position A:

Pixel from the left Image - Close to the edge - Less contribution to the perception

Pixel from the right Image - Far from the edge - More contribution to the perception (Close to the center)

Using local alphas – Feathering

Ioverlap = αlocal x Ileft + (1 - αlocal) x Iright

Distance Transform

DL1 DL2 DL3

DR1 DR1 DR3

DLk αk = ----------------------- DLk + DRk

Different Window – Different Result

+

Window 25 Pixel 50 Pixel 200 Pixel

Smaller Image = Harder to tell differences

2 2 2

Lost details at each step: Laplacian Pyramid

2Σ

Lossless Recovery

2Σ 2Σ

Pyramid Blending – Multi-resolution

Apple Laplacian Pyramid

Orange Laplacian Pyramid

+

+

+

Blend Laplacian Pyramid

+

2

Σ

2

Σ

2

Σ

Pyramid Blending – Better Result

+

Feathering Pyramid

Macro & Micro Panoramic

Panoramic Picture of Mars’ Surface

Conclusion

•  Alpha Blending: Simplest Solution

•  Image Feathering: Good for stitching

•  Pyramid Blending: Good for creating

•  More advanced algorithm: Poisson Blending

Panoramic Picture of Mars’ Surface

FunPlace!

1.  Burt,PeterJ.,andEdwardH.Adelson."TheLaplacianpyramidasacompactimagecode."CommunicaAons,IEEETransacAonson31.4(1983):532-540.

2.  hNp://graphics.cs.cmu.edu/courses/15-463/2005_fall/www/Lectures/Pyramids.pdf

3.  hNp://compvisionlab.wordpress.com/2013/05/13/image-blending-using-pyramid/

4.  hNps://www.youtube.com/watch?v=NiGcuurpV5o&feature=plcp

5.  hNps://www.facebook.com/photo.php?\id=10151443406289338&set=a.10150895951034338.524501.776664337&type=1&theater(PhotoshoppedbyZchBielak)

6.  hNp://cs.brown.edu/courses/cs129/results/proj2/baebi/7.  hNp://cs.brown.edu/courses/cs129/results/proj2/marroz/

8.  AirandSpaceMuseuminWashingtonD.C.

References