Noise filter for Bayer pattern image data
First Claim
Patent Images
1. An image filter for filtering a Bayer pattern, comprising:
- an interpolation algorithm that joins together the digital information provided by differently colored adjacent pixels in a plurality of color channel Bayer patterns; and
the filter being adaptive and operable directly on the Bayer patterns for each color channel to remove noise while simultaneously preserving picture detail; and
wherein at least two filter masks are used, one for a green channel and the other for a red and blue channels, and wherein the filter masks for the red and blue channels have an identical pattern comprising neighboring pixels arranged in a square pattern surrounding a center red/blue target pixel while the filter mask for the green channel has a pattern comprising eight neighboring pixels arranged in a diamond pattern surrounding a center green target pixel.
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Abstract
A method of filtering an image filter is disclosed. The filter is provided for a digital camera including image sensors sensitive to light, a color filter placed over sensitive elements of the sensors and patterned according to a Bayer mosaic pattern layout and an interpolation algorithm joining together the digital information provided by differently colored adjacent pixels in said Bayer pattern. The filter is adaptive and includes a noise level computation block for operating directly on a said Bayer pattern data set of for each color channel thus removing noise while simultaneously preserving picture detail.
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Citations
17 Claims
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1. An image filter for filtering a Bayer pattern, comprising:
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an interpolation algorithm that joins together the digital information provided by differently colored adjacent pixels in a plurality of color channel Bayer patterns; and the filter being adaptive and operable directly on the Bayer patterns for each color channel to remove noise while simultaneously preserving picture detail; and wherein at least two filter masks are used, one for a green channel and the other for a red and blue channels, and wherein the filter masks for the red and blue channels have an identical pattern comprising neighboring pixels arranged in a square pattern surrounding a center red/blue target pixel while the filter mask for the green channel has a pattern comprising eight neighboring pixels arranged in a diamond pattern surrounding a center green target pixel.
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2. An image filter for filtering a Bayer pattern, comprising:
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an interpolation algorithm that joins together the digital information provided by differently colored adjacent pixels in a plurality of color channel Bayer patterns; the filter being adaptive and operable directly on the Bayer patterns for each color channel to remove noise while simultaneously preserving picture detail; a determination function that examines a current pixel in a processing window, determines its color, and selects an appropriate filtering mask for that color; a difference calculator that determines an absolute value difference between said current pixel and the values of a plurality of its neighboring similarly colored pixels in said processing window; a maximum and minimum determination function that computes a maximum and minimum one of the determined distance values; and a noise level computation function that estimates a noise level associated with said processing window. - View Dependent Claims (3, 4)
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5. A method for filtering noise in a digital image, comprising the steps of:
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interpolating the digital image to join together digital information provided by differently colored adjacent pixels and produce a plurality of color channel Bayer patterns; scanning sequentially row by row through a selected Bayer pattern; providing a processing window for each color channel of said Bayer pattern data set, the processing windows for the red and blue channels being identical, while the processing window for the green channel being different, and each processing window having a target pixel and a plurality of neighboring pixels; selecting a filtering mask and a corresponding processing window in dependence on color of a current target pixel; and filtering the target pixel by computing a noise level of the color channel and providing a filtered pattern format depending on said noise level. - View Dependent Claims (6)
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7. An image filter for processing a color channel of Bayer pattern data, comprising:
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a working window function that identifies a target pixel in the Bayer pattern data along with a plurality of neighboring pixels to the target pixel having a common color; a comparator function that compares the common color target and neighboring pixels; and a filtering function that determines a filtered value for the target pixel based on the common color target and neighboring pixels comparison by; resisting change in the target pixel value when the comparison indicates dramatic difference between the target and neighboring pixels; and encouraging change in the target pixel value when the comparison indicates minimal difference between the target and neighboring pixels. - View Dependent Claims (8, 9, 10, 11)
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12. An image filter for processing a color channel of Bayer pattern data, comprising:
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a working window function that identifies a target pixel in the Bayer pattern data along with a plurality of neighboring pixels to the target pixel having a common color; a comparator function that compares the common color target and neighboring pixels; and a filtering function that determines a filtered value for the target pixel based on the common color target and neighboring pixels comparison that; preserves image detail where the comparison indicates dramatic difference between the target and neighboring pixels; and corrects noisy pixels where the comparison indicates minimal difference between the target and neighboring pixels. - View Dependent Claims (13, 14, 15, 16)
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17. An image filter for filtering a Bayer pattern, comprising:
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an interpolation algorithm that joins together the digital information provided by differently colored adjacent pixels in a plurality of color channel Bayer patterns; and the filter being adaptive and operable directly on the Bayer patterns for each color channel to remove noise while simultaneously preserving picture detail; and wherein at least two filter masks are used, one for a green channel and the other for a red and blue channels, and wherein the filter masks for the red and blue channels have an identical pattern consisting only of plural neighboring pixels arranged in a square pattern surrounding a center red/blue target pixel while the filter mask for the green channel has a pattern consisting only of plural neighboring pixels arranged in a diamond pattern surrounding a center green target pixel.
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Specification