Methods, apparatuses and systems for piecewise generation of pixel correction values for image processing

An imaging device comprising:

• a pixel array, the pixel array outputting a plurality of pixel values;
• and
• an image processing unit coupled to the pixel array, the image processing unit being operable to correct a responsiveness of pixels in the array by applying respective positional gain adjustment values to the pixel values,
• wherein a positional gain adjustment value for a particular pixel value is the value of a piecewise-quadratic correction function in a first direction based on respective sets of parameters corresponding to the particular pixel value, wherein the respective sets of parameters defining the piecewise-quadratic correction functions in the first direction are determined using a plurality of piecewise-quadratic correction functions in a second direction.

An imaging device comprising:

• a pixel array, the pixel array outputting a plurality of pixel values;
• a processor coupled to the pixel array for correcting responsiveness of pixels in the array by applying respective pixel correction values to the pixel values, the processor being operable to determine in real time a pixel correction value for a particular pixel value as the value of a piecewise-quadratic correction function in a first direction based on a respective set of parameters corresponding to the row of the particular pixel value, wherein the respective set of parameters for the piecewise-quadratic correction function in the first direction are determined using a plurality of piecewise-quadratic correction functions in a second direction;
• and
• a memory device, wherein sets of parameters defining the plurality of piecewise-quadratic correction functions in the second direction are stored in the memory device.

An imaging device, comprising:

• a pixel array;
• and
• a processor coupled to the pixel array for applying correction factors to pixel values read out from the pixel array, the processor being operable to determine and apply correction factors based on a piecewise-quadratic correction function in a first direction along the pixel array,
• wherein the processor determines a correction factor corresponding to a particular pixel value using a set of parameters to determine the piecewise-quadratic correction function in the first direction, the set of parameters being determined by a plurality of piecewise-quadratic correction functions in a second direction.

An imaging device, comprising:

• a pixel array;
• and
• a processor coupled to the pixel array for applying correction factors to pixel values read out from the pixel array, the processor being operable to determine and apply correction factors, wherein the correction factors are determined in accordance with:
• F(x, y)=Fx(x)+G, wherein F(x, y) is the correction factor, Fx(x) is a piecewise-quadratic correction function in the x-direction, and G is a universal gain value, and
• wherein each Fx(x) is defined in terms multiple Fy(y) functions, wherein Fy(y) is a piecewise-quadratic correction function in the y-direction.

A storage medium comprising:

• a set of instructions stored on the medium and executable on a processor to perform the acts of:
• determining corrected pixel values associated with a first row of pixels using a piecewise-quadratic correction function in a first direction along the array according to a first set of parameters;
• and
• determining corrected pixel values associated with each subsequent row of pixels using the piecewise-quadratic correction function in the first direction according to respective sets of parameters, wherein the respective sets of parameters are determined by a plurality of piecewise-quadratic correction functions in a second direction along the array.

A digital camera comprising:

• a lens;
• a pixel array for capturing an image received through the lens;
• and
• an image processing circuit which is operable to determine a set of pixel correction values for use in correcting pixel values corresponding to pixels of a captured image and to correct the pixel values for a captured image using the determined set of pixel correction values, wherein the pixel correction values are determined based on a piecewise-quadratic correction function in a first direction along the pixel array,
• wherein the image processing circuit determines a pixel correction value corresponding to a particular pixel value using a respective set of parameters to calculate the piecewise-quadratic correction function in the first direction, the respective set of parameters being determined by a plurality of piecewise-quadratic correction functions in a second direction.

An image processing system comprising:

• a processor;
• and
• an imaging system coupled to the processor, the imaging system comprising:
• a pixel array, the pixel array outputting a plurality of pixel values;
• and
• an image processing circuit for processing the plurality of pixel values, the image processing circuit being operable to determine and apply respective pixel correction values to the pixel values,
• wherein a pixel correction value for a particular pixel value is the value of a piecewise-quadratic correction function in a first direction based on a respective set of parameters corresponding to the particular pixel value,
• wherein the pixel value processing circuit further comprises means for determining the respective sets of parameters for the piecewise-quadratic correction function in the first direction using a plurality of piecewise-quadratic correction functions in a second direction.