Thomson Trt Defense

Xavier Noreve

Michel Terre

Luc Fety

The analysis of an image of the field of observation from a heat camera by bands of n lines prompts the appearance of streaks or 'striping' in certain zones of the image, all these zones constituting a 'striping space'. The device for the implementation of the method includes means to determine a base of orthonormal functions H and V, generating a vector space of functions for which the values taken, at each point of the image, represent the luminance values of all the types of striping, means to modelize the striping exhibited by the image in determining the coefficients of distribution of this striping on the basic functions, means to synthesize the striping, in determining the luminance values of the striping from the coefficients of correlation and from the values of he basic functions, and, finally, means to substract the luminance values of the synthesized striping from the luminance values of the initial image.

Device for the correction of images from a sensor causing a periodic

According to the method, after a step for the digital processing of the video signal of the image analyzed by rows, there is determined, for each row, on the basis of the distribution of the mean light energy values below and above each position of the row, a step modelling function, the jump position of which gives the position of the horizon in this row. The device used to implement this method includes a sampler of the video signal coupled with a flip flop memory through an accumulator which adds up the luminance values row by row, and a processor which, on the basis of the distribution of the mean light energy levels, computes the signal to be subtracted from the digital video signal by means of a subtractor. The disclosed method and device can be applied to the detection of the horizon from an image analyzed by columns or by lines.

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Paris, France

Xavier Noreve