From 9b6a9bd9333b8bce3d0498fd92162c5db21d691b Mon Sep 17 00:00:00 2001 From: TimothyLottes Date: Wed, 9 Nov 2016 08:33:46 -0500 Subject: [PATCH] Add files via upload --- 20160127.html | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ index.html | 1 + 2 files changed, 49 insertions(+) create mode 100644 20160127.html diff --git a/20160127.html b/20160127.html new file mode 100644 index 0000000..2ff380a --- /dev/null +++ b/20160127.html @@ -0,0 +1,48 @@ +
+

20160127 - Temporal AA Neighborhood Clamp

+
+Thoughts too long for the twitter thread on this, +back from my memory of working on this problem... +
+
+In TAA the purpose of the neighborhood clamp is to remove ghosting. +Using the surrounding local neighborhood of the current frame +to bound the color of the reprojection of the prior frame. +Many techniques have been tried here, +including using the min and max of the neighborhood as an AABB to clip to. +Clipping to two AABBs one in RGB and the other in YCoCg, for a tigher bound. +Etc. +It is possible to continue down this path adding more complex and tigher bounds shapes, +and doing better clipping for when colors are out of bounds. +But ultimately it seemed like this exploration had passed the optimum !/$ point, +and settled on the following low-tech solution for the fast path, +
+ +
+Why? +
+Lets reduce the problem to strictly monochrome. +The complex 3D bound shape is now reduced to a 1D segment +defined by the min and max of the neighborhood. +When the neighborhood is high frequency and high contrast, +which is common say with a field of grass, +the min can be a shadow tone, and the max can be a bright highlight. +Then just about any reprojection passes the neighborhood clamp without adjustment, +and ghosting results. +Or even if the reprojection gets clampped, it will be at the extreme ends of the large segment, +resulting in distortion to the image. +
+
+Ultimately this kind of approach cannot solve the problem at hand, +so I stopped searching in this specific solution space... + + + +
+ + + diff --git a/index.html b/index.html index a60de36..b25ccb3 100644 --- a/index.html +++ b/index.html @@ -45,6 +45,7 @@ Below this is active random migration (456 prior posts still to filter through) 2016
20161018 - Fixed Point Rounding
20160715 - LED Displays
+20160127 - Temporal AA Neighborhood Clamp

2015
20151222 - Random Holiday 2015