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Systems and methods for lens shading correction

  • US 9,743,057 B2
  • Filed: 05/31/2012
  • Issued: 08/22/2017
  • Est. Priority Date: 05/31/2012
  • Status: Active Grant
First Claim
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1. An image signal processing circuit comprising:

  • an interface configured to receive image data from an image sensor of an imaging device; and

    pipe processing logic configured to perform a set of processing operations on the image data, wherein one of the set of processing operations is a lens shading correction operation, and wherein the pipe processing logic comprises lens shading correction logic configured to;

    receive an input pixel of the image data;

    access a gain grid by pointing to the gain grid in external memory;

    determine the location of the input pixel within a lens shading correction region defined within an imaging frame of the image sensor relative to the gain grid having a plurality of grid points distributed horizontally and vertically, wherein each of the plurality of grid points is associated with a lens shading gain;

    determine an interpolated lens shading gain for the input pixel using bi-linear interpolation of the lens shading gains associated with a nearest set of grid points enclosing the input pixel;

    determine a radial lens shading gain as a function of a global gain parameter associated with the color of the input pixel and a radial distance between the center of the lens shading correction region and the location of the input pixel;

    apply the interpolated lens shading gain and the radial lens shading gain to the input pixel; and

    collect and store information related to;

    one or more pixel values inputted to the lens shading correction logic, one or more pixel values outputted from the lens shading correction logic, or both.

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