Temporal anti-aliasing (TAA) is a
spatial anti-aliasing
In digital signal processing, spatial anti-aliasing is a technique for minimizing the distortion artifacts (aliasing) when representing a high-resolution image at a lower resolution. Anti-aliasing is used in digital photography, computer graphics ...
technique for computer-generated video that combines information from past frames and the current frame to remove
jaggies
"Jaggies" is the informal name for artifacts in raster images, most frequently from aliasing, which in turn is often caused by non-linear mixing effects producing high-frequency components, or missing or poor anti-aliasing filtering prior to samp ...
in the current frame. In TAA, each pixel is sampled once per frame but in each frame the sample is at a different location within the pixel. Pixels sampled in past frames are blended with pixels sampled in the current frame to produce an anti-aliased image.
[Brian Kari, Epic Game]
"High Quality Temporal Supersampling"
TAA compared to MSAA
Prior to the development of TAA,
MSAA was the dominant anti-aliasing technique. MSAA samples (renders) each pixel multiple times at different locations within the frame and averages the samples to produce the final pixel value. In contrast, TAA samples each pixel only once per frame, but it samples the pixels at a different locations in different frames. This makes TAA faster than MSAA. In parts of the picture without motion, TAA effectively computes MSAA over multiple frames and achieves the same quality as MSAA with lower computational cost.
TAA compared to FXAA
TAA and FXAA both sample each pixel only once per frame, but FXAA does not take into account pixels sampled in past frames, so FXAA is simpler and faster but can not achieve the same image quality as TAA or MSAA.
Implementation
Sampling the pixels at a different position in each frame can be achieved by adding a per-frame "jitter" when rendering the frames. The "jitter" is a 2D offset that shifts the pixel grid, and its X and Y magnitude are between 0 and 1.
[Ziyad Baraka]
"Temporal Anti Aliasing – Step by Step"
When combining pixels sampled in past frames with pixels sampled in the current frame, care needs to be taken to avoid blending pixels that contain different objects, which would produce
ghosting or motion-blurring artifacts. Different implementation of TAA have different ways of achieving this. Possible methods include:
* Using motion vectors from the game engine to perform
motion compensation
Motion compensation in computing, is an algorithmic technique used to predict a frame in a video, given the previous and/or future frames by accounting for motion of the camera and/or objects in the video. It is employed in the encoding of video d ...
before blending.
* Limiting (clamping) the final value of a pixel by the values of pixels surrounding it.
TAA compared to DLSS
Nvidia
Nvidia CorporationOfficially written as NVIDIA and stylized in its logo as VIDIA with the lowercase "n" the same height as the uppercase "VIDIA"; formerly stylized as VIDIA with a large italicized lowercase "n" on products from the mid 1990s to ...
's
DLSS operates on similar principles to TAA. Like TAA, it uses information from past frames to produce the current frame. Unlike TAA, DLSS does not sample every pixel in every frame. Instead, it samples different pixels in different frames and uses pixels sampled in past frames to fill in the unsampled pixels in the current frame. DLSS uses machine learning to combine samples in the current frame and past frames, and it can be thought of as an advanced TAA implementation.
[Edward Liu, NVIDI]
"DLSS 2.0 - Image Reconstruction for Real-time Rendering with Deep Learning"
/ref>[yellowstone]
"How DLSS 2.0 works (for gamers)"
See also
* Multisample anti-aliasing
Multisample anti-aliasing (MSAA) is a type of spatial anti-aliasing, a technique used in computer graphics to remove jaggies.
Definition
The term generally refers to a special case of supersampling. Initial implementations of full-scene anti-al ...
* Fast approximate anti-aliasing
Fast approximate anti-aliasing (FXAA) is a screen-space anti-aliasing algorithm created by Timothy Lottes at Nvidia.
FXAA 3 is released under a public domain license. A later version, FXAA 3.11, is released under a 3-clause BSD license.
Algor ...
* Deep learning super sampling
Deep learning super sampling (DLSS) is a family of real-time deep learning image enhancement and upscaling technologies developed by Nvidia that are exclusive to its RTX line of graphics cards, and available in a number of video games. The goal o ...
* Deep learning anti-aliasing
Deep learning anti-aliasing (DLAA) is a form of spatial anti-aliasing created by Nvidia. DLAA depends on and requires Tensor Cores available in Nvidia RTX cards.
DLAA is similar to deep learning super sampling (DLSS) in its anti-aliasing method, ...
* Supersampling
Supersampling or supersampling anti-aliasing (SSAA) is a spatial anti-aliasing method, i.e. a method used to remove aliasing (jagged and pixelated edges, colloquially known as "jaggies") from images rendered in computer games or other computer p ...
* Deinterlacing
Deinterlacing is the process of converting interlaced video into a non-interlaced or Progressive scan, progressive form. Interlaced video signals are commonly found in analog television, digital television (HDTV) when in the 1080i format, some D ...
References
{{DEFAULTSORT:Temporal Anti-Aliasing
Anti-aliasing algorithms