Directional bilateral filtering of raw image data
AssigneeApple Inc.
InventorsSheng Lin, David R. Pope
Life of this patent
Estimating the term…
Abstract
Embodiments relate to directional bilateral filtering of a raw image. For each pixel in the image, a block of pixels surrounding that pixel is used for filtering. When the block of pixels in a Bayer pattern have directionality, directional filter coefficients are used instead of default filter coefficients. To obtain a directional tap, a directional filter coefficient is attenuated by an attenuation factor that differs based at least on the location of the pixels in the pixel block. The directional taps are blended with non-directional taps derived from the default filter coefficients using a weight representing confidence on the directionality. The filtered pixel values are then obtained by multiplying pixel values with corresponding taps.
Claims20
An apparatus for processing an image, comprising:
- a bilateral filter circuit configured to:
- determine whether a block of pixels in a raw image has directionality, the block of pixels including pixels of multiple colors;
- determine, responsive to determining that the block of pixels has the directionality, taps for pixels of a same color in the block by processing directional filter coefficients corresponding to the directionality and a location of each pixel within the block;
- and
- obtain each of pixel values of a filtered raw image by multiplying the taps to corresponding pixel values in the pixels of the same color and adding the multiplied values;
- and
- a demosaicing circuit configured to perform demosaicing on a version of the filtered raw image.
A method for processing an image, comprising:
- determining whether a block of pixels in a raw image has directionality, the block of pixels including pixels of multiple colors;
- determining, responsive to determining that the block of pixels has the directionality, taps for pixels of a same color in the block by processing directional filter coefficients corresponding to the directionality and a location of each pixel within the block;
- obtaining each of pixel values of a filtered raw image by multiplying the taps to corresponding pixel values in the pixels of the same color and adding the multiplied values;
- and
- demosaicing of a version of the filtered raw image.
An imaging system, comprising:
- an image capturing device configured to capture a raw image;
- a bilateral filter circuit configured to:
- determine whether a block of pixels in the raw image has directionality, the block of pixels including pixels of multiple colors;
- determine, responsive to determining that the block of pixels has the directionality, taps for pixels of a same color in the block by processing directional filter coefficients corresponding to the directionality and a location of each pixel within the block;
- and
- obtain each of pixel values of a filtered raw image by multiplying the taps to corresponding pixel values in the pixels of the same color and adding the multiplied values;
- and
- a demosaicing circuit configured to perform demosaicing on a version of the filtered raw image.
Dependencies are inferred from the claim text.