Deep Learning

Object Detection with Deep Learning

One of the most interesting topics in the Coursera Deep Learning specialization is the “YOLO” algorithm for object detection. I often find it helpful to describe algorithms in my own words to solidify my understanding, and that is precisely what I will do here. Readers likely will prefer the original paper and its sequel.

Thoughts on the Coursera Deep Learning Specialization

I recently completed the Deep Learning specialization on Coursera from deeplearning.ai. Over five courses, they go over generic neural networks, regularization, convolutional neural nets, and recurrent neural nets. Having completed it, I would say the specialization is a great overview, and a jumping off point for learning more about particular techniques. I wouldn’t say I have an in-depth understanding of all the material, but I do feel like I could go off and read papers and understand them, which is maybe all I could expect.

Distribution of Local Minima in Deep Neural Networks

The “unreasonable effectiveness of deep learning” has been much discussed. Namely, as the cost function is non-convex, any optimization procedure will in general find a local, non-global, minimum. Actually, algorithms like gradient descent will terminate (perhaps because of early stopping) before even reaching a local minimum. For many experts in optimization, this seems like a bad thing. Concretely, it seems like the performance of networks trained in this way would be much worse than other optimization-based systems where we are in fact able to find the global minimum, such as logistic regression.

Computer Vision Cheat Sheet

I am currently working through Convolutional Neural Networks, the fourth course in the Coursera specialization on Deep Learning. The first week of that course contains some hard-to-remember equations about filter sizes and padding and striding and I thought it would be helpful for me to write it out for future reference.

Deep Learning Checklist

Recently I started the Deep Learning Specialization on Coursera. While I studied neural networks in my masters program (from Andrew Ng himself!), that was a long time ago and the field has changed considerably since then. I am supplementing the course by reading Deep Learning by Ian Goodfellow, Yoshua Bengio, and Aaron Courville, which I will refer to as GBC16.