Systems and methods for lens shading correction
First Claim
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.
1 Assignment
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Accused Products
Abstract
Systems and methods for correcting intensity drop-offs due to geometric properties of lenses are provided. In one example, a method includes receiving an input pixel of the image data, the image data acquired using an image sensor. A color component of the input pixel is determined. A gain grid is determined by pointing to the gain grid in external memory. Each of the plurality of grid points is associated with a lens shading gain selected based upon the color of the input pixel. A nearest set of grid points that enclose the input pixel is identified. Further, a lens shading gain is determined by interpolating the lens shading gains associated with each of the set of grid points and is applied to the input pixel.
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Citations
11 Claims
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1. An image signal processing circuit comprising:
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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. - View Dependent Claims (2, 3, 4, 5)
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6. An electronic device, comprising:
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an imaging device comprising an image sensor; and image processing circuitry configured to process image data acquired using the image sensor, wherein the image processing circuitry comprises; lens shading correction logic configured to; determine the location of an input pixel of the image data within a lens shading correction region defined within an imaging frame of the image sensor relative to a gain grid stored in external memory and accessed by pointing to an address of the gain grid in external memory, 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; and apply the interpolated lens shading gain and the radial lens shading gain to the input pixel; and lens shading correction statistics logic configured to; 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.- View Dependent Claims (7, 8, 9, 10, 11)
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Specification