Method and device to enhance image quality in digital video processing systems using dithering
AssigneeBarco N.V.
InventorRonny Van Belle
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Abstract
A processing chain for a digital image signal applies a dither pattern, having a first spectrum, to the image signal at a point in the processing chain. A further noise pattern is applied to the image signal during the processing chain. The noise pattern has a second spectrum which is configured such that the combination of the first spectrum and second spectrum results in a more continuous spectrum. Another aspect describes a noise pattern which can be used as an offset dither pattern for digital images, especially before color bit depth reduction. The noise pattern has an array of values which are linearly distributed across a range, with each value in the range occurring an equal number of times.
Claims28
A method of processing a digital image signal in a processing chain between an image generator and an image display, the digital image signal being a video signal, wherein a dither pattern is applied to the image signal at a point in the processing chain, the dither pattern has a first energy spectrum, the method comprising the steps:
- applying a noise pattern to the image signal in the processing chain,
- the noise pattern having a second energy spectrum, which is configured such that the combination of the first energy spectrum of the dither pattern and the second energy spectrum of the noise pattern results in a more continuous energy spectrum,
- wherein the first energy spectrum of the dither pattern has a set of peaks and the second energy spectrum of the noise pattern has minima at positions corresponding to at least some of the peaks in the first energy spectrum, and
- wherein the first and second energy spectrums are energy spectrums that are functions of frequency.
A method of generating a noise pattern for use in a digital image processing chain between an image generator and an image display, where a dither pattern is applied to the image signal at a point in the processing chain, the image signal being a video signal, the dithering signal having a first energy spectrum, the method comprising the steps:
- generating via a processor, the noise pattern with a second energy spectrum, which is configured such that the combination of the first energy spectrum and second energy spectrum results in a more continuous energy spectrum, wherein the first energy spectrum has a set of peaks and the second energy spectrum has minima at positions corresponding to at least some of the peaks in the first energy spectrum, and wherein the first and second energy spectrums are energy spectrums that are functions of frequency.
A digital image processing device comprising:
- a processing block for applying a noise pattern to a digital video signal, wherein a dither pattern is applied to the video signal at a point in the processing chain, the dither pattern having a first energy spectrum, wherein the processing block is configured to apply a noise pattern to the video signal in the processing chain, the noise pattern having a second energy spectrum which is configured such that the combination of the first energy spectrum and second energy spectrum results in a more continuous energy spectrum,
- wherein the first energy spectrum of the dither pattern has a set of peaks and the second energy spectrum of the noise pattern has minima at positions corresponding to at least some of the peaks in the first energy spectrum, and
- wherein the first and second energy spectrums are energy spectrums that are functions of frequency.
Dependencies are inferred from the claim text.