# Two Shots of Green Screen Please!

## Метаданные

- **Канал:** Two Minute Papers
- **YouTube:** https://www.youtube.com/watch?v=sTe_-YOccdM
- **Дата:** 16.05.2020
- **Длительность:** 4:32
- **Просмотры:** 156,143
- **Источник:** https://ekstraktznaniy.ru/video/14130

## Описание

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Their instrumentation for this paper is available here:
https://app.wandb.ai/stacey/greenscreen/reports/Two-Shots-to-Green-Screen%3A-Collage-with-Deep-Learning--VmlldzoxMDc4MjY

📝 The paper "Background Matting: The World is Your Green Screen" is available here:
https://grail.cs.washington.edu/projects/background-matting/

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## Транскрипт

### Introduction []

dear fellow scholars this is two minute papers with dr. Carew's on a fajita when shooting feature-length movies or just trying to hold meetings from home through zoom or Skype we can make our appearance a little more professional by hiding the maps we have in the background by changing it to something

### Hiding Maps [0:17]

more pleasing of course this can only happen if we have an algorithm at hand that can detect what the foreground and the background is which typically is easiest when we have a green screen behind us that is easy to filter for even the simpler algorithms out there however of course not everyone has a green screen at home and even for people who do may need to hold meetings out there in the wilderness unfortunately this would mean that the problem statement is the exact opposite of what we've said or in other words the background is almost anything else but a green screen so is it possible to apply some of these newer neural network based learning algorithms to tackle this problem well this technique promises to make this problem much easier to solve

### Solution [1:06]

all we need to do is take two photographs one with and one without the test subject and it will automatically predict an L format that isolates the test subject from the background if you have a closer look you'll see the first part of why this problem is difficult this mat is not binary so the final compositing process is given not is only foreground or only background for every pixel in the image but there are parts typically around the silhouettes and hair that need to be blended together this blending information is contained in the gray parts of the image and are especially difficult to predict let's

### Results [1:46]

have a look at some results you see the captured background here and the input video below and you see that it is truly a sight to behold it seems that this person is really just casually hanging out in front of a place that is definitely not a whiteboard even works in cases where the background or the camera itself is slightly in motion very cool it really is much better

### Flickering [2:15]

than these previous techniques where you see the temporal coherence is typically a problem this is the flickering that you see here which arises from the vastly different predictions for the Alpha mat between neighboring frames in the video opposed to previous methods this new technique shows very little of that excellent

### Outputs [2:37]

now we noted that a little movement in the background is permissible but it really means just a little if things get too crazy back there the outputs are also going to break down this wizardry all works through a generative adversarial network in which one neural network generates the output results this by itself

### Detector Network [2:57]

didn't work all that well because the images used to train this neural network can differ greatly from the backgrounds that we record out there in the world in this work the authors bridge the gap by introducing a detector network that tries to find faults in the output and tell the generator if it has failed to fool it as the two neural networks Duke it out they work and improve together yielding these incredible results note that there are plenty of more contributions in the paper so please make sure to have a look for more details what a time to be alive what you

### Outro [3:34]

see here is an instrumentation of this exact paper we have talked about which was made by weights and biases I think organizing these experiments really showcases the usability of their system weights and biases provides tools to track your experiments in your deep learning projects their system is designed to save you a ton of time and money and it is actively used in projects at prestigious labs such as open AI Toyota research github and more and the best part is that if you are an academic or have an open-source project you can use their tools for free it really is as good as it gets make sure to visit them through wnb comm slash papers or just click the link in the video description and you can get a free demo today our thanks to weights and biases for their long-standing support and for helping us make better videos for you thanks for watching and for your generous support and I'll see you next time