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Image to Image Translation with
Conditional Adversarial Networks
Presented by: Shahbaz Ali Khan
Image to Image Translation
? Different representations of scenes
? Example: One concept in English and Urdu
? RGB Edges
? RGB Gray-scale
2
Image to Image Translation
? Primary objective remains the same
¨C Map pixels to pixels
? Why use different approaches?
? Why not a general purpose solution?
? Problem: Hand-crafted loss functions
¨C Telling the network what we want to minimize
3
Discriminative vs. Generative
? Discriminative: identify objects i.e. determine
class scores
? Generative: capture the underlying distribution
and produce samples from that distribution
4
Generative Adversarial Networks
? The solution to this problem is provided by
GANs
? GANs learn a loss function
? Two neural networks (example Art forgery)
¨C Generator (G): synthesizes images
¨C Discriminator (D): identifies fakes
? A zero sum game is played to reach equilibrium
5
GANs vs. Conditional GANs
6
U-Net Architecture
7
U-Net Architecture
? Underlying structure doesn¡¯t change during
translation
? Allow low level info to shuttle across the network
? Motivated by use of L1 loss
8
PatchGAN Discriminator
9
Experiments
Architecture labels Semantic labels to street
to photo scene
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Experiments
Map to aerial photo BW to color
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Experiments
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Experiments
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Experiments: Failure Cases
14
Evaluation of Results
? Amazon Mechanical Turk
¨C Is this image real or fake?
? FCN score
¨C Object recognition by off-the-shelf recognition
systems
15
Evaluation of Results
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Evaluation of Results
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Evaluation of Results
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Evaluation of Results
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Evaluation of Results
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Conclusion
? Investigation of Conditional GANs as a general
purpose solution for image to image translation
tasks.
? Presentation of effective architecture for Generator
and Discriminator.
? Lesser accuracy for tasks like semantic segmentation
? Failure cases: (highly) sparse inputs
21
Thank You!
22

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Editor's Notes

  1. Give example of the L2 loss function here that leads to blurry result from page 2 para 2
  2. No need to specify loss functions See what is zero sum game