Looking at a Black Hole with Python

A brief note on how deep learning and specially GAN's can be used to reconstruct the VLBI Images efficiently. And how Python can help in that!

View talk here: https://cloudproject.hosted.panopto.com/Panopto/Pages/Viewer.aspx?id=8b73aab5-428e-49ac-bff8-aa9b015eafea

Lightning talk delivered at Python in Astronomy 2019 @ Space Telescope Science Institute, Baltimore, United States of America

Transcript

1. Looking at a Black Hole with Python Shreyas Bapat (@astroshreyas) PyAstro 2019 @ STScI Baltimore (USA), 31 July 2019
2. The BIG Problem Data! 1. (2nd Doesn’t exist)
3. http://vlbiimaging.csail.mit.edu/
4. The incomplete fourier space!
5. Inverse Modeling ▪ Put 0’s in every other place ▪ Take a simple Inverse Fourier Transform. ▪ Tada! Perform some extra steps to make the image less blurry!. 5
6. Regularized Maximum Likelihood ▪ Predicting what values would come at the empty places. ▪ Basically one of the technique used GMMs! ▪ Inverse fourier transform. ▪ Tada! No need to perform any more steps!. 6
8. Don’t bash me xD! But why not try with Deep Neural Networks! 8
9. CNN’s Convolutional Neural Networks have outperformed almost every other technique in image-based problems! 9
10. One night in 2014, Ian Goodfellow went drinking to celebrate with a fellow doctoral student who had just graduated. He had an idea: What if you pitted two neural networks against each other? Generative Adversarial Networks (GAN) were born! 10
11. MR Imaging Very similar to VLBI. More number of points in Fourier Space, more the time taken for one image. My experience Results Using Residual Learning, Got really sharp images from undersampled fourier space. 11
12. My process is easy Fill the remaining places with 0’s Manipulate the 0’s to some other value Take the Fourier Transform 12
14. ~93% Reconstruction Accuracy! 14
15. What if we use GANs? 15
16. GAN : A minimax game between two neural networks Generator tries to generate the image! Discriminator tries to judge if the image is good to go! 16
20. Stay in touch! GitHub : @shreyasbapat Twitter : @astroshreyas Email : hello@shreyasb.com 20