Apple patent is for method, apparatus for adjusting chroma, luma for a video signal
Posted by Dennis Sellers 
Nov 20, 2008 at 1:04pm
An Apple patent (number 20080284915) for a method and apparatus for adjusting chroma and luma for a video signal has appeared at the US Patent & Trademark Office. The invention relates to techniques for adjusting chroma and luma values for a video signal.
According to Apple, a system that adjusts chroma and luma values for a video signal is presented. During operation, the system receives a matrix of coefficients, which when applied to the chroma values and the luma values of a video signal produces substantially the same result as performing a sequence of discrete operations on the chroma values and the luma values, wherein the sequence of discrete operations includes one or more color-representation-conversion operations and one or more processing amplifier operations. For a given pixel of the video signal, the system performs a matrix-multiplication operation between a matrix representation of the chroma values and the luma values for the given pixel and the matrix of coefficients to produce a modified pixel.
Here’s Apple’s background on the invention: “Modern graphics processing units (GPUs) include dedicated hardware resources to efficiently perform computationally intensive graphics operations. Two such graphics operations are processing amplifier (proc amp) operations and color representation operations. A proc amp operation adjusts the hue, saturation, contrast, and brightness of a set of pixels. Color representation conversion operations convert the chroma and luma values of a set of pixels from one color representation to another color representation (e.g., from Y’CbCr to R’B’G’). In some cases, both a proc amp operation and one or more color representation conversion operations are required to process an image. In such cases, the graphics operations are typically serialized, wherein the GPU sequentially performs a series of discrete mathematical operations for each operation for each pixel. Unfortunately, even with powerful GPUs, performing these graphics operations across millions of pixels becomes computationally expensive and time consuming. Hence, what is needed is a method and an apparatus for adjusting chroma and luma values for a video signal without the problems described.”
The inventors are Samuel A. Gigueroa and Jay D. Zipnick. The graphic below illustrates a computer system in accordance with an embodiment of the present invention.
“Macsimum News” is a Proud supporter of Planet Gumbo, which feeds the hungry. We urge you to help them in their efforts.
Article Information
Comment on this Article Print this Article Email this Article Digg This
Contributor
Dennis Sellers
Dennis has been a newspaper editor/reporter (seven years) and teacher (seven years). He has over 4,000 magazine, newspaper and online articles to his credit. He has also covered the Mac and tech industries for over a decade for such online publications as MacCentral, MacMinute and now MacsimumNews.
