Offset compensation

An image processing method comprising:

• receiving a plurality of image frames from a detector array, wherein each image frame includes a measurement array of pixel values, the plurality of image frames corresponding to a plurality of measurement arrays;
• computing a difference array from each measurement array of said plurality of measurement arrays, to provide a plurality of difference arrays, a different difference array corresponding to each individual measurement array of said plurality of measurement arrays, wherein the elements of each said difference array comprise:
• a selected element which is set to zero;
• elements which are computed as a difference between:
• a corresponding measurement array element;
• and
• another element of the measurement array;
• or
• a linear combination of other elements of the measurement array;
• averaging said plurality of difference arrays to provide an average difference array;
• and
• determining an offset array using said average difference array.

An image processing method comprising:

• receiving an image frame from a detector array, which image frame including a measurement array of pixel values;
• computing a difference array where a selected element of said difference array is set to zero, and where each element of said difference array except for said selected element is computed as a difference between:
• a corresponding measurement array element;
• and
• another element of the measurement array;
• or
• a linear combination of other elements of the measurement array;
• receiving previous difference data comprising one or more previously computed difference arrays associated with one or more previously received measurement arrays;
• determining an average difference array using said difference array and said one or more previously computed difference arrays;
• and
• determining an offset array using said average difference array.

A detector system comprising:

• a detector array comprising a plurality of detectors, which detector array configured to provide image frames each image frame including a measurement array of pixel values, each pixel value provided by a detector of said plurality of detectors;
• a processor configured to:
• receive measurement arrays from said detector array;
• compute, for each measurement array, a difference array, to provide a plurality of difference arrays, where a selected element of each said difference array is set to zero, and where each element of said difference array except for said selected element is computed as a difference between:
• a corresponding measurement array element;
• and
• another element of the measurement array;
• or
• a linear combination of other elements of the measurement array;
• determine an average difference array from said plurality of difference arrays;
• and
• determine an offset array using said average difference array;
• correct a received image frame, using said offset array to provide a corrected measurement array.