CS 194-26 Project #3: Fun with Frequencies and Gradients!


The purpose of this project was to explore different approaches to image blending.

Part 1: Frequency Domain

Part 1.1: Warmup

Here is a cat picture I captured on holiday.

original catto (fuzzy)
sharpened catto

Part 1.2: Hybrid Images

original derek (not nutmeg)
original nutmeg (not derek)
a familiar face
a lizard that looks like a bearded dragon

Watch out! You can't blend just any old Derek and Nutmeg!

random derek
random nutmeg
this is less than ideal

The correct Derek and Nutmeg in the frequency domain:

Part 1.3: Gaussian and Laplacian Stacks

Lincoln and Gala, and Mona Lisa decomposed:

Additional examples:

Part 1.4: Multiresolution Blending

In this section, each laplacian layer is blended at a different intensity, with the help of a gaussian masking stack. One failure case is combining faces of different skin tones.

lighter blending
stronger blending
democratic leaders
a happy potato that never asked to become a yam

Part 2: Gradient Domain Fushion

In these examples, the goal is to transplant an object from one background to another. The object is masked by hand, and adjusted such that it blends into the new background. The adjusted object is computed to minimize the difference in gradient from the original object, and to minimize the difference from border pixels. This often results in a shift of hue.

Part 2.1: Toy Problem

original woody
woody reconstructed from gradient

Part 2.2: Poisson Blending

When we try to add parrot friends to the whale shark's house, they appear too dark because the hue of the addition image is shifted to merge the sky and water. The overall effect improves slightly when the sky is made darker, but the blend is not smooth.

bird friends
whale shark and humans
mask to blend
adjusted mask

Here are some images that worked a little bit better:

spooky ghost
spooky ghost in faculty hall
a squirbo in berkeley
now he has way too many students
gorthaur the cruel
a nice day in mordor
nice turtle
hearst pool with different colored water
nice turtle in hearst pool
sample penguin
sample slope
penguin on slope

A comparison of techniques:

original apple
original orange
simple average
hybrid aporange
hybrid oraple
using stacks and a mask
poisson blending mask
poisson blending