US 8,477,149 B2 · Real-time chromakey matting using image statistics

Abstract

A method, system and computer readable media for real-time chromakey matting using image statistics. To identify the chroma key spectrum, the system/method executes in three stages. In an off-line training stage, the system performs semi-automatic calibration of the chroma key parameterization. In the real-time classification stage, the system estimates the alpha matte on a GPU. Finally, an optional error minimization stage improves the estimated matte, accounting for misclassifications and signal noise. Given the resulting matte, standard alpha blending composites the virtual scene with the video feed to create the illusion that both worlds coexist.

Claims20

Dependent claims

A method for generating an alpha matte based on chromakey information in real-time, comprising:

(a) off-line training comprising calibration of chroma key parameterization by sampling chroma color and statistically analyzing invariant properties of chroma key pixels using principal component analysis (PCA) to transform the chroma color into a transformed color space;
(b) real-time classification via a processor comprising estimating an alpha matte using a classifier to classify pixels, p, in a video frame using geometric objects whose boundaries define opacity used for alpha matting;
(c) outputting a resulting alpha matte to allow for alpha blending to composite a virtual scene with a video feed.

A system for generating an alpha matte based on chroma key information in real-time, said system comprising:

a display device;
a memory;
and a processor with hardware and software components for:
(a) off-line training comprising calibration of chroma key parameterization by sampling chroma color and statistically analyzing invariant properties of chroma key pixels using principal component analysis (PCA) to transform the chroma color into a transformed color space;
(b) real-time classification via a processor comprising estimating an alpha matte using a classifier to classify pixels, p, in a video frame using geometric objects whose boundaries define opacity used for alpha matting;
(c) outputting a resulting alpha matte to allow for alpha blending to composite a virtual scene with a video feed.

3 more elements

An article of manufacture comprising:

a computer usable medium having computer readable code means embodied therein for:
(a) off-line training comprising calibration of chroma key parameterization by sampling chroma color and statistically analyzing invariant properties of chroma key pixels using principal component analysis (PCA) to transform the chroma color into a transformed color space;
(b) real-time classification via a processor comprising estimating an alpha matte using a classifier to classify pixels, p, in a video frame using geometric objects whose boundaries define opacity used for alpha matting;
(c) outputting a resulting alpha matte to allow for alpha blending to composite a virtual scene with a video feed.

1 more element

Dependencies are inferred from the claim text.

Facts

Application

12/752,238Filed 1 Apr 2010 · us provisional application

Priority

1 Apr 2009

Published

US 2010/0277471 A14 Nov 2010

Granted

2 Jul 2013

Term ends

Not estimatedThe source records don’t support an estimate.

Classification7 codes

G06V 10/56
Extraction of image or video features: relating to colour
G06F 18/2135
Feature extraction, e.g. by transforming the feature space; Summarisation; Mappings, e.g. subspace methods: based on approximation criteria, e.g.…
G06V 10/7715
Processing image or video features in feature spaces; using data integration or data reduction, e.g. principal component analysis [PCA] or…:…
H04N 9/75
For obtaining special effects: chroma key

Real-time chromakey matting using image statistics

Life of this patent

Real-time chromakey matting using image statistics

Life of this patent

Abstract

Claims20