Method for correcting images obtained by an array of photosensitive points

摘要

A method for correcting an image obtained by a matrix of photosensitive points finds particular utility when the matrix is subjected to an electromagnetic disturbance. The method of correction comprises a first step of row-by-row reading of the matrix. The signals read during a first reading of each row represent the charges accumulated subsequent to exposure of the matrix to luminous radiation and make it possible to form, for each column of the matrix, a discrete signal. The signals read during a second reading represent the charges accumulated in the absence of exposure and form, for each column of the matrix, a discrete signal. In a second step of the method, a signal corresponding substantially to the signal which would have been formed at the time of the first reading in the absence of exposure is determined. In a third step, the signal is subtracted column by column from the signal.

主权项

1. A method for correcting an image obtained by a photosensitive device comprising photosensitive points organized as a matrix of Nl rows by Nc columns, each photosensitive point configured to accumulate charges during exposure to luminous radiation, the method comprising:
reading, row-by-row, at instants t=2n and t=2n+1 of signals representative of the charges accumulated at each n photosensitive point, where n being an integer lying between 0 and N−1, where N is an integer lying between 2 and the number Nl of rows of the matrix, the signals of one and the same row being read simultaneously, a determined duration Tsampling separating two successive reading instants, the signals read at the instants t=2n being called useful signals representing the charges accumulated at the various photosensitive points subsequent to exposure of these points to useful luminous radiation, the signals that are read at the instants t=2n+1 being called offset signals representing the charges accumulated at the various photosensitive points in the absence of exposure to radiation, the useful signals forming discrete signal Xreal(n) for each column of the matrix and the offset signals forming discrete signal OF(n) for each column of the matrix; determining, for each discrete signal OF(n) corresponding to a column of the matrix, a signal OFX(n) representing the charges accumulated at the photosensitive points readable at the instants t=2n in the absence of exposure to radiation, the signals OFX(n) being determined by correcting the discrete signals OF(n); and subtracting, for each column of the matrix, the signal OFX(n) from the corresponding signal Xreal(n).