Method for correcting the space noise of an image sensor by luminescence limitation
AssigneeCommissariat a l'Energie Atomique
InventorGilles Chammings
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Abstract
The invention relates to matrix image sensors, and it relates more particularly to a method for correcting the fixed spatial noise of the matrix. The signal (Sij,n) obtained from each pixel (Pij) during a large number of successive images is collected; for each pixel, an approximate value (Mij) of an average of the signal obtained from the pixel during this large number of images is determined; the signal obtained from each pixel is corrected by adding to it the difference between a reference average value (M0) and the approximate average value. The approximate average is obtained by determining high and low limit values taken by the signal obtained from the pixel during the large number of images, and by calculating a median between these high and low limit values.
Claims10
A method of processing signals obtained from the pixels of a matrix image sensor, this method comprising the follow steps:
- a. a signal obtained from each pixel during a large number of successive images is collected;
- b. for each pixel, an approximate value of an average of the signal obtained from the pixel during this large number of images is determined;
- c. the signal obtained from each pixel is instantaneously corrected according to the determined approximate average value and a reference average value common to all the pixels;
- and
- d. a corrected signal is transmitted from a circuit associated with the pixel, wherein the approximate average value is obtained by determining a high and a low limit value taken by the signal obtained from the pixel during the large number of images, and by calculating a central value between these high and low limit values.
A matrix image sensor comprising, for each pixel, an individual digital circuit associated with the pixel, this individual circuit comprising:
- a. means for calculating an approximate average value of the signal obtained from the pixel during a large number of preceding images, the approximate average value being obtained by determining high low limit values taken by the signal obtained from the pixel during the large number of images and by calculating a central value between these high and low limit values;
- and
- b. means for correcting the signal obtained from the pixel according to the determined approximate average value and according to a reference average value common to all the pixels;
- and
- c. means for transmitting a corrected signal from a circuit associated with the pixel.
Dependencies are inferred from the claim text.