Thoughts on data science, statistics and machine learning.
Weighted Loss Functions for Instance Segmentation
This post is a follow up to my talk, Practical Image Classification & Object Detection at PyData Delhi 2018. You can watch the talk here:
and see the slides here.
I spoke at length about the different kinds of problems in computer vision and how they are interpreted in deep learning architectures. I spent a fair bit of time on instance and semantic segmentation (for an introduction to these problems, watch Justin Johnson’s lecture from the Stanford CS231 course here). In short, semantic segmentation deals with designating each pixel of an image as belonging to a class, and instance segmentation deals with identifying which instance of a class each pixel belongs to. The following images show an example of semantic versus instance segmentation.
Book Review: In Dubious Battle - John Steinbeck
I have a pretty good Steinbeck collection, but this wasn’t a book I was going to read anytime soon. But I recently came across the movie adaptation and decided that other Steinbeck titles could wait. James Franco and John Steinbeck is a very attractive combination.
First of all, this book is not about communism. The eponymous battle is not a battle of the classes. It’s more of a battle men fight with themselves. The Communist Party is just a minor device in the plot. A much bigger and apparent device is collectivism. After all, in East of Eden, Steinbeck has defended passionately the creative spirit of the individual mind, so a collectivist is perhaps the last thing he’d be.
How Not to Ask Questions After a Talk
Dedicated to the memory of Mrutyunjay Mishra (M2). He was a torrent of ideas. He encouraged me to write this post because as much as he talked endlessly without pausing to breathe, he hated wasteful discourse.
New Delhi, January 2024
PyCon India 2017 ended last weekend in Delhi. The conference escaped the infamous winter smog-storm by a whisker. In the last few years, PyCon India has grown to become the largest PyCon outside of North America, with over a thousand participants attending from all over the country. The conference itself was driven by a team of about 50 volunteers.
Book Review: The View from the Cheap Seats - Neil Gaiman
I can’t think of a single fantasy character that would be Neil Gaiman. I’m tempted to think that he’s like Santa Claus, but he’s not the sort who’d care if someone was being naughty. He’s not Dumbledore or Gandalf either - he’d rather be your friend than your mentor. He’s not even the Dream of the Endless, since he’s not aware of how powerful he is.
Reading Gaiman’s nonfiction is like meditation that clears and even expands your mind. It’s like a cool refreshing drink after a long day of rigour (I read The View From the Cheap Seats after the underwheling chore of reading Joseph Conrad’s Heart of Darkness). This book is satisfying and disquieting at the same time. You will discover a lot more to read, and at the same time, reading Gaiman has a normalizing effect on whatever you have read. I think Gaiman has unwittingly achieved a standardization of literature that ought to be widely adopted. The book is scattered with dreamy encounters with giants like Stephen King and Terry Pratchett (among many more), punctuated with brutal shocks that he felt about the Syrain refugee crisis or Charlie Hedbo, grounded by his account of the bauble of the Oscars. What he doesn’t deal in is mediocrity and trivia.