![https://s3-us-west-2.amazonaws.com/secure.notion-static.com/635b9851-f634-4501-ad00-3a0b5e131939/Untitled.png](https://s3-us-west-2.amazonaws.com/secure.notion-static.com/635b9851-f634-4501-ad00-3a0b5e131939/Untitled.png)
![https://s3-us-west-2.amazonaws.com/secure.notion-static.com/62f27622-b9bc-429f-a682-a96d19369bd8/Untitled.png](https://s3-us-west-2.amazonaws.com/secure.notion-static.com/62f27622-b9bc-429f-a682-a96d19369bd8/Untitled.png)
滤波核可以设置阈值,砍掉边缘的贡献
周围像素 $j$ 包括了自己,some_of_weights
在这里不会是零,因为有包括了自己。
颜色是三通道的
Problem of Gaussian filtering:
- Also blurs the boundary
- The boundary is the high frequency that we want to keep
![https://s3-us-west-2.amazonaws.com/secure.notion-static.com/1cda4cbe-231c-4587-ad0a-bac5c5756e1a/Untitled.png](https://s3-us-west-2.amazonaws.com/secure.notion-static.com/1cda4cbe-231c-4587-ad0a-bac5c5756e1a/Untitled.png)
Bilateral Filtering 双边滤波
- Observation
- The boundary → drastically changing colors
- Idea
- How to keep the boundary?
- Let pixel $j$ contribute less if its color is too different to $i$
- Simply add more control to the kernel
![https://s3-us-west-2.amazonaws.com/secure.notion-static.com/07d9ec2a-a671-4021-a80d-bbfa06a171a3/Untitled.png](https://s3-us-west-2.amazonaws.com/secure.notion-static.com/07d9ec2a-a671-4021-a80d-bbfa06a171a3/Untitled.png)
问题:会不会把与噪声的差异也算进去了?
Joint Bilateral Filtering / Cross Bilateral Filtering(意思一样)
- Observation
- Gasussian filtering: 1 metric (distance)
- Bilateral filtering: 2 metrics (position distance and color distance)
- Especially good at denoising path traced rendering results!
- Use G-buffers
- G-buffers are noise-free as they are not generated by multi-bounces
![https://s3-us-west-2.amazonaws.com/secure.notion-static.com/3e03de68-bff0-4e92-a5bd-af4407bea4d0/Untitled.png](https://s3-us-west-2.amazonaws.com/secure.notion-static.com/3e03de68-bff0-4e92-a5bd-af4407bea4d0/Untitled.png)