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

A method of correcting responsiveness of pixels of an imager device, the method comprising the acts of:

• inputting a plurality of pixel values from the pixels, the plurality of pixel values forming an input image;
• determining a positional gain adjustment value for each pixel value;
• and
• applying the respective positional gain adjustment values to the pixel values to form an output image,
• wherein determining the positional gain adjustment values comprises:
• determining positional gain adjustment values of a first row of pixel values using a first generic piecewise-quadratic correction function as defined by a first set of stored parameters;
• and
• determining positional gain adjustment values of each subsequent row of pixel values using, the first generic piecewise-quadratic correction function as defined for each subsequent row by respective sets of stored parameters,
• wherein the sets of calculated parameters defining the first generic function for each subsequent row are determined in real time and the values may differ between rows, and
• wherein the sets of calculated parameters defining the first generic function for each subsequent row are determined by a second generic piecewise-quadratic function as defined, for each calculated parameter defining the first piecewise-quadratic function, by a respective one of a plurality of second sets of stored parameters.

A method of determining corrected pixel values for a plurality of pixel values associated with a pixel array, the method comprising the acts of:

• determining corrected pixel values for pixel values in accordance with:
• P(x,y)=PIN(x,y)*F(x,y),
• wherein P(x, y) is the corrected pixel value, PIN(x, y) is the pixel value associated with the pixel array and F(x, y) is a correction function,
• wherein F(x, y) is determined in accordance with F(x, y)=Fx(x)+G, wherein Fx(x) is a piecewise-quadratic correction function in the x-direction and G is a global offset value,
• wherein each Fx(x) is defined by a set of parameters and wherein the set of parameters is determined separately for each row,
• 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, and
• wherein each Fy(y) function is defined by a set of stored parameters.

An imaging device, comprising:

• a pixel array;
• and
• a programmable image processing unit coupled to the pixel array for applying pixel correction values to pixel values read out from the pixel array, the programmable image processing unit being operable to determine and apply pixel correction values based on a first generic piecewise-quadratic correction function as defined by a plurality of first sets of calculated parameters, the values of which vary by row, and
• wherein the values of the plurality of first sets of parameters are calculated using a second generic piecewise-quadratic correction function as defined, for each calculated parameter defining the first generic piecewise-quadratic function, by a respective one of a plurality of second sets of stored parameters.