Method for correcting images output by a detector without temperature regulation and detector implementing such a method

摘要

Image correction methods and systems are disclosed that correct raw values, including, subsequent to closing the shutter, acquiring a current raw value table, determining an offset correction table for the current temperature of the detector as a function of the current table and a set of stored raw value tables, and correcting the stream of raw values using the offset correction table. A maintenance process includes testing a condition for replacing a table of the current set with the current table, and if the condition is met, replacing the table of the current set with the current table. This test includes determining whether there is a new set of tables obtained by replacing a table from the current set with the current table that is more relevant than the current set with regard to subsequently determining an offset table.

主权项

1. A method for correcting images produced by an array of bolometers of a detector without temperature regulation, said array including a retina of bolometric membranes arranged in the focal plane of optics and suspended above a substrate in which there is formed a readout circuit that outputs a stream of raw signal values that correspond to each bolometer in the array in relation to an observed scene, with the detector also including a shutter arranged between the optics and the retina, the method comprising, in an operating mode in which the ambient temperature conditions of the detector are free to change:
a first step of closing the shutter and acquiring and storing in a memory of the detector:
a current table of raw values corresponding to an image of the shutter by the array of bolometers; anda temperature of the detector during acquisition of said current raw value table, a second step of determining and storing, in the memory of the detector, an offset correction table for the current temperature of the detector as a function of:
the current raw value table and the temperature associated thereof; anda current set of raw value tables corresponding to images of the shutter by the array of bolometers previously stored in the detector's memory and temperatures of the detector associated respectively with each of these tables at the time they were acquired, said temperatures being stored in the detector's memory; and a third step of correcting the stream of raw values using the offset correction table, wherein the method further comprises, subsequent to the acquisition of a current raw value table, a maintenance process for maintaining of the current set of raw value tables, including: testing a condition for replacing a table of said current set with the current raw value table; and if said condition is met, replacing the table of said current set of tables with the current raw value table and replacing the acquisition temperature of the replaced table with the acquisition temperature of the current raw value table, said test including the determination, on the basis of at least one predetermined criterion, of whether there is a new set of tables obtained by replacing a table from the current set with the current table that is more relevant than the current set to subsequent determination of the offset table.