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US 8,576,313 B2Granted
Color filters and demosaicing techniques for digital imaging
AssigneeThe Invention Science Fund I, LLC
InventorNathan P. Myhrvold
Life of this patent
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Abstract
Color filter arrays or mosaics are provided for imaging a scene with diffraction limited optics. A distribution of color types in a color filter array is biased toward smaller wavelengths to avoid or reduce loss of spatial resolution information at higher wavelengths due to a larger extent of diffraction at the higher wavelengths. Demosaicing methods for reconstructing a partial or full color image from raw image data involve applying correction factors to account for diffraction. The correction factors are based on pixel size and/or a measure of the extent of diffraction (e.g., an Airy disk diameter) for each wavelength in the color filter array.
Claims27
A color imaging device, comprising:
- an array of color responsive elements,
- wherein the array of color responsive elements includes a number (NB) of a first type of color responsive elements sensitive to a blue (B) spectral region, a number (NG) of a second type of color responsive elements sensitive to a green (G) spectral region, and a number (NR) of a third type of color responsive elements sensitive to a red (R) spectral region,
- wherein NB is at least three,
- wherein the numbers of the first, second and third types of color responsive elements are ordered as NB>NG and NB>NR;
- and
- wherein the array of color responsive elements includes a two dimensional array of transmissive blue (B), green (G), red (R) and white (W) color filter pixels.
3 more elements
An imaging device, comprising:
- a focusing element having a focal length (F);
- an aperture coupled to the focusing element, the aperture having an effective diameter (D);
- and
- an array of color responsive elements disposed at or about the focal length,
- wherein the color sensitive elements correspond to a set of separate color channels (i), where i=1, 2, . . . n,
- wherein each color channel i is associated with a respective color wavelength λi,
- wherein a number (N1) of color responsive elements corresponding to the color channel having a lowest wavelength λ1 in the array is at least three and is greater than a number (N2) of color responsive elements corresponding to the color channel having a higher wavelength λ2 in the array, and
- wherein the numbers Ni of color responsive elements corresponding to color channels i are ordered so that N1>N2≧ . . . ≧Nn.
5 more elements
A method, comprising:
- providing an array of color responsive elements;
- and directing light from a scene on to the array color responsive elements,
- wherein the array of color responsive elements includes a number (NB) of a first type of color responsive elements sensitive to a blue (B) spectral region, a number (NG) of a second type of color responsive elements sensitive to a green (G) spectral region, and a number (NR) of a third type of color responsive elements sensitive to a red (R) spectral region,
- wherein NB is at least three,
- wherein the numbers of the first, second and third types of color responsive elements are ordered as NB>NG≧NR, and
- wherein the array of color responsive elements includes a two dimensional array of transmissive blue (B), green (G), red (R) and white (W) color filter pixels.
3 more elements
A method for imaging a scene, comprising:
- providing a focusing element having a focal length (F);
- providing an aperture coupled to the focusing element, the aperture having an effective diameter (D);
- and
- providing an array of color responsive elements disposed in an image plane at or about the focal length,
- wherein the color responsive elements correspond to a set of separate color channels (i), where i=1, 2 . . . n,
- wherein each color channel i is associated with a respective color wavelength λi,
- wherein a number (N1) of color responsive elements corresponding to the color channel having a lowest wavelength λ1 in the array is at least three and greater than a number (N2) of color responsive elements corresponding to the color channel having a higher wavelength λ2 in the array,
- wherein the focusing element is configured to direct light from the scene on the array of color responsive elements through the aperture, and
- wherein the numbers Ni of color responsive elements corresponding to color channels i are ordered so that N1>N2≧ . . . ≧Nn.
6 more elements
An imaging device, comprising:
- a focusing element having a focal length (F);
- an aperture coupled to the focusing element, the aperture having an effective diameter (D);
- and
- an array of color responsive elements disposed at or about the focal length,
- wherein the color sensitive elements correspond to a set of separate color channels (i), where i=1, 2, . . . n,
- wherein each color channel i is associated with a respective color wavelength λi,
- wherein a number (N1) of color responsive elements corresponding to the color channel having a lowest wavelength λ1 in the array is at least three and is greater than a number (N2) of color responsive elements corresponding to the color channel having a higher wavelength λ2 in the array, and
- wherein the array of color responsive elements includes a two dimensional array of transmissive blue (B), green (G), red (R) and white (W) color filter pixels.
5 more elements
A method for imaging a scene, comprising:
- providing a focusing element having a focal length (F);
- providing an aperture coupled to the focusing element, the aperture having an effective diameter (D);
- and
- providing an array of color responsive elements disposed in an image plane at or about the focal length, wherein the color responsive elements correspond to a set of separate color channels (i), where i=1, 2 . . . n, wherein each color channel i is associated with a respective color wavelength λi, wherein a number (N1) of color responsive elements corresponding to the color channel having a lowest wavelength λ1 in the array is at least three and greater than a number (N2) of color responsive elements corresponding to the color channel having a higher wavelength λ2 in the array,
- wherein the focusing element is configured to direct light from the scene on the array of color responsive elements through the aperture, and
- wherein the array of color responsive elements includes a two dimensional array of transmissive blue (B), green (G), red (R) and white (W) color filter pixels.
3 more elements
Dependencies are inferred from the claim text.