Patent ID: 6563100
Filing Date: 2003-05-13
Classification: H04N

Abstract:
A method of processing measurement data having errors due to unpredictable non-uniformity in illumination of a detector from a scene viewed by an array of detectors in a sensor, said method providing an accurate estimate of radiance at a geometric point in the instantaneous field of view (IFOV) of said detectors, comprising:a. selecting a first one of said detectors across whose IFOV an accurate estimate of actual illumination is desired; b. selecting a group of said detectors surrounding said first one of said detectors, said group designated as a largest sub-array representing a largest data window of detectors, said group established about said first one of said detectors as the center of said group; c. constructing a nested set representing a unique group of sub-arrays of said detectors, each said sub-array designated as a unique data window, in said nested set, wherein each said sub-array fits within said largest sub-array, said sub-arrays decreasing in size such that each smaller said sub-array fits within an immediately preceding said sub-array and encompasses an immediately succeeding said sub-array until said first selected detector is the last said sub-array in said nested set;d. summing the irradiances, E, measured for each said data window to yield a value of E for each said data window; e. summing said IFOV for each said detector in each said data window to yield associated values of IFOV for each said data window; f. calculating associated preliminary estimates of radiance, L, from the relationship, L=E/associated IFOV; g. establishing a relationship between said radiance values, L, versus corresponding said associated IFOV values in a FOV domain, wherein said FOV domain is defined as a two-dimensional graph of IFOV versus L on which a smooth continuous curve may be fit to points plotted to represent said relationship;h. extrapolating to obtain a value for radiance, L, at a zero-width IFOV, wherein said extrapolating yields said accurate estimate for radiance at said zero-width IFOV located at a geometric point within said WFOV of said first selected detector; andi. repeating steps a-h for all said detectors of interest in said array, wherein completion of steps a-i yields a set of numerical values for derived radiance from each said detector of interest in said array, and wherein said derived radiance values enable formation of an image with greater accuracy in said radiance values, increased contrast, some spatial de-blurring, and better resolution as compared to processing images without following said steps a-i.