Aloha guys!
I'm verty excited to announce that I have joined Facebook Reality Labs (FRL) as a Research Scientist! Before that, I interned twice at Facebook AI Research, and now I will work in the FRL division, which focuses on virtual and augmented reality. Moving from academy to industry, I hope that I will still have enough freedom in choosing research directions 😉.

Here's a very recent article from Googe Brain that uses diffusion models for super-resolution.

The results are shocking! Their model beats the GAN-based SOTA method. The video shows an example of how a 64x64 picture is upscaled to 1024x1024. But no source code yet.

🌀 Project page
📝 Paper

I also wrote about OpenAI paper on diffusion models earlier.

OpenAI disbands its robotics research team. This is exactly the same team that, for example, taught a robotic arm to solve a Rubik's cube using Reinforcement Learning. This decision was made because the company considers more promising research in areas where physical equipment is not required (except for servers, of course), and there is already a lot of data available. And also for economic reasons, since Software as a Services is a business with a much higher margin. Yes, the joke is that the non-profit organization OpenAI is considered more and more about profit. This is understandable because it takes a lot of money to create general artificial intelligence (AGI) that can learn all the tasks that a person can do and even more.

It's no secret that research in the field of robotics is also a very costly activity that requires a lot of investment. Therefore, there are not so many companies involved in this. Among the large and successful, only Boston Dynamics comes to mind, which has already changed several owners. Did you know that in 2013 Google acquired Boston Dynamics, then Google also scaled down its robotics research program, and in 2017 sold Boston Dynamic to the Japanese firm SoftBank. The adventures of Boston Dynamics did not end there, and in December 2020 SoftBank resold 80% of the shares (a controlling stake) to the automaker Hyundai. This looks somehow fishy as if every company understands after a few years that it is still difficult to make a profit from Boston Dynamics and sells it to another patsy.

In any case, it is very interesting to observe which focus areas are chosen by the titans of AI research. But I'm a bit sad that robots are still lagging behind.

German startup aims to become "Europe's OpenAI"

The German startup Aleph Alpha, which is based in Heidelberg, Germany (the city where I did my PhD), recently raised $ 27M in a Series A round. The task, they set themselves ambitious (even too much) - they want to create another breakthrough in AI, something similar to OpenAI GPT-3.

The company was founded in 2019, and, strangely, I discovered it only today. I looked at their ML team. And I have not found a single person with any major scientific achievements (say on the level of Professor). I got disappointed. Their ML team includes 3 recent PhD students and Connor Leahy, who is known for co-founding EleutherAI. EleutherAI is a non-profit organization that was created to reproduce and open-source GPT-3 model. Perhaps they bet on Connor, but, frankly speaking, Connor is not a researcher, he has no scientific publications, and EleutherAI is simply reproducing results of OpenAI. When OpenAI was founded, it was immediately clear that they got a stellar team, which would certainly produce something cool.

My impressions are controversial. Aleph Alpha has partnerships with German government agencies. They promote themselves in the style of "we are Europe's last chance claim a place in the field of AI", "we will be based purely in Europe and will be pushing European values and ethical standards." They also promise to be more open than OpenAI (lol) and commit to open-source. Although, perhaps, they will just create some kind of large platform with AI solutions and sit on the government funding. It will be a kind of AI consulting, they even have a job posted on their website for this purpose - AI Delivery & Consulting. The whole affair smacks of a government cover-up like in the case of Palantir (at least partially).

I'm not a startup expert, but it seems like Europe is very hungry for innovation. They want to keep up with the United States and China. Therefore, they give out the bucks at the first opportunity, especially if the company promises to work closely with the government. What do you think about this, gentlemen?

Paint Transformer: Feed Forward Neural Painting with Stroke Prediction

Earlier I wrote about a style transfer that, instead of optimizing pixels, optimizes directly parameterized brush strokes. A new work has been released, it uses Transformer architecture to predict stroke parameters using one (well, almost one) forward-pass of the network. In fact, their transformer is made in the spirit of a recurrent network.

Four forward passes of the original image in different resolutions are made through the network, starting from downsapled 16 times to the original one. At each next forward puss, a rendered canvas with strokes predicted in the previous passes is also added to the input as well as the original image in a higher resolution. Thus, the network gradually adds new strokes to the canvas, starting with larger ones (they are painted on a low resolution canvas), and ending with smaller ones (on a high resolution canvas). The network is trained on synthetic data generated online.

📝 Paper
🛠 Code

One more example of a synthesised image by the paper mentioned above.

Rethinking Style Transfer: From Pixels to Parameterized Brushstrokes

[Another recent "style transfer with brushstrokes" paper from my colleagues in Heidelberg University ]

In this paper, images are stylized by optimizing parameterized brush strokes instead of pixels as well. In order to backpropagate teh error through the rendered brushstrokes, the authors came up with a simple differentiable rendering of strokes, each of which is parameterized with a Bezier curve.

The results are excellent. You can also add constraints to the shape of your brush strokes by drawing a couple of lines over the photo. The only drawback is that it works for a rather long time (10-20 minutes per 1MP picture), since this is an iterative optimization, and at each iteration a forward-pass through VGG-16 newtwork is required.

🌀 Project website
🛠 Source code

Here's another example of how the algorithm mentioned above works. The horse is stylized in Kirchner's style.

The differences with the classic pixel-by-pixel method by Gatys et al. are very explicit. The new method, of course, significantly perturbs the content in contrast to Gatys, but the style really looks more similar to the German expressionist Kirchner and we see prominent brush strokes.

🔥StyleGAN3 by NVIDIA!

Do you remember the awesome smooth results by Alias-Free GAN I wrote about earlier? The authors have finally posted the code and now you can build your amazing projects on it.

I don't know about you, but my hands are already itching to try it out.

🛠 Source code
🌀 Project page
⚙️ Colab

​​On Neural Rendering

What is Neural Rendering? In a nutshell, neural rendering is when we take classic algorithms for image rendering from computer graphics and replace a part of the pipeline with neural networks (stupid, but effective). Neural rendering learns to render and represent a scene from one or more input photos by simulating the physical process of a camera that captures the scene. A key property of 3D neural rendering is the disentanglement of the camera capturing process (i.e., the projection and image formation) and the representation of a 3D scene during training. That is, we learn an explicit (voxels, point clouds, parametric surfaces) or an implicit (signed distance function) representation of a 3D scene. For training, we use observations of the scene from several camera viewpoints. The network is trained on these observations by rendering the estimated 3D scene from the training viewpoints, and minimizing the difference between the rendered and observed images. This learned scene representation can be rendered from any virtual camera in order to synthesize novel views. It is important for learning that the entire rendering pipeline is differentiable.

You may have noticed, that the topic of neural rendering, including all sorts of nerfs-schmerfs, is now a big hype in computer vision. You might say that neural rendering is very slow, and you'd be right. A typical training session on a small scene with ~ 50 input photos takes about 5.5 hours for the fastest method on a single GPU, but neural rendering methods have made significant progress in the last year improving both fidelity and efficiency. To catch up on all the recent developments in this direction, I highly recommend reading this SOTA report "Advances in Neural Rendering".

The gif is from Volume Rendering of Neural Implicit Surfaces paper.

I'm back people! After some pause I decided to continue posting in this channel. I promise to select the most interesting papers and write at least 1-2 posts per week.

Cheers,
Artsiom