Chair of
Multimedia Communications and Signal Processing
Prof. Dr.-Ing. André Kaup

Histogram-Based Correction of Chrominance Sub-Sampling Artifacts for Screen Content Coding Applications

Supervisor:M.Sc. Andreas Heindel (Room 01.178)
Faculty:Prof. Dr.-Ing. André Kaup
Student:Neumüller, Clemens

Web conferencing and remote desktop applications require the desktop of one computer to be encoded and transmitted over a network, often the internet, to be displayed on a remote screen. Video compression techniques have to be used to achieve the low data rate needed for real time transmission. However, common video codecs like the well-known H.264/AVC and also the latest standards H.265/HEVC and VP9 are primarily optimized for natural video sequences. To this end, they work using the YCbCr color space involving 4:2:0 chrominance sub-sampling. However, this may lead to annoying artifacts with screen content, e.g. at sharp edges or text.

An efficient approach to correct these artifacts is given by using information extracted from the histogram. Histogram models can be employed to reconstruct the original chrominance values. However, the number and distribution of colors in the histogram is crucially influencing the reconstruction capabilities.

The task in this project is the refinement of existing and the design of new histogram models to accomplish the color reconstruction. Moreover, strategies to avoid the incorrect application of the models leading to a corruption of the improved output should be investigated.

TypeResearch Internship