Methods and apparatuses that reduce noise in image signals
First Claim
Patent Images
1. A method of adjusting a color imaging pixel signal of an imaging pixel from a pixel array, the method comprising:
- determining a first demosaiced value of the imaging pixel signal using a first demosaicing method;
determining a second demosaiced value of the imaging pixel signal using a second demosaicing method employing noise reduction;
determining an edge value; and
determining a noise reduced value of the imaging pixel signal as a function of the first demosaiced value, the second demosaiced value, and the edge value.
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Abstract
Methods and apparatuses for noise reduction of imager pixels signals. A weighted combination based on the presence of edges of two calculated demosaiced signals is used to produce a noise reduced signal. The noise reduced signal may be sharpened based on a calculated luminance of the two demosaiced signals.
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Citations
35 Claims
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1. A method of adjusting a color imaging pixel signal of an imaging pixel from a pixel array, the method comprising:
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determining a first demosaiced value of the imaging pixel signal using a first demosaicing method; determining a second demosaiced value of the imaging pixel signal using a second demosaicing method employing noise reduction; determining an edge value; and determining a noise reduced value of the imaging pixel signal as a function of the first demosaiced value, the second demosaiced value, and the edge value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of adjusting a color imaging pixel signal of an imaging pixel from a pixel array, the method comprising:
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determining a first demosaiced value of the imaging pixel signal using a first demosaicing method; determining a second demosaiced value of the imaging pixel signal using a second demosaicing method employing noise reduction and using pixel signal averaging; determining an edge value by detecting the presence of an edge in at least a portion of the array at an area containing an imaging pixel associated with the signal being adjusted; determining a weight as a function of the edge value, a luminance of the second demosaiced value, and at least a constant; determining a noise reduced value of the imaging pixel signal as a weighted combination of the first demosaiced value and the second demosaiced value, wherein the weight determines the amount of pixel averaging by weighting the demosaiced values; determining a minimum luminance value necessary to produce a sharpening effect on the noise reduced value as a function of the luminance of the first demosaiced value; determining a high-frequency sharpening signal value as a function of the luminance of the first demosaiced value, the second demosaiced value, and the minimum luminance value; and determining a sharpened value as a function of the noise reduced value and the sharpening signal value.
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15. An imaging device comprising:
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an imaging sensor comprising an array of imaging pixels; a signal processing circuit for adjusting signals from the array, the signal processing circuit comprising; a first demosaicing module configured to determine a first demosaiced value of an imaging pixel signal using a first demosaicing method; a second demosaicing module configured to determine a second demosaiced value of the imaging pixel signal using a second demosaicing method employing noise reduction; an edge detection module configured to determine an edge value by detecting the presence of an edge in at least a portion of the array at an area containing an imaging pixel associated with the signal being adjusted; and a noise reduction module configured to determine a noise reduced value of the imaging pixel signal as a function of the first demosaiced value, the second demosaiced value, and the edge value. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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22. A method of demosaicing a color image signal of an imaging pixel, the method comprising:
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selecting a kernel having a kernel size and a center pixel location for each viable color pattern for a kernel of the kernel size such that each selected kernel has a unique color pattern; determining the color pixel configurations of the selected kernels for each color; selecting a subset of pixels from the color pixel configurations for each selected kernel for each color; and assigning a pixel weight to each pixel within the subsets, the pixel weight being derived as a function of at least one of;
the color the pixels, an edge crossing the kernels, a shape of the subset of pixels, a location of the pixel within the kernel, a zipper effect, and pixel noise. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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Specification