Abstract: Apparatus for processing digitized images, the apparatus being of the type comprising a matrix memory (104) of pixels (106) organized as N lines (108) by P columns (110), together with processing means (130) for determining which pixels (106) are in the excited state by reading the memory (104). The processing means (130) operate by determining and storing the address of an excited pixel (106) that occupies an extreme position in a line or a column position, by switching said pixel (106) to a non-excited state, and by reiterating these operations until none of the pixels (106) is excited.

Abstract: The occurrence and frequency of a periodic component embedded in a composite waveform including noise is detected by real time calculating the autocorrelation function of the waveform and deducing the frequency of the periodic component from the value of the autocorrelation function coefficients. An analog-to-digital converter periodically transforms the waveform into samples having q bits. The samples are delayed by a predetermined time interval .DELTA.t and multiples thereof, to derive 2n delayed samples, x.sub.i, x.sub.i-1 . . . x.sub.i-2n. The delayed samples are multipled to derive 2n products, such that the first n products are represented by x.sub.1 .multidot.x.sub.i-k and the second n products are represented by x.sub.1-n .multidot.x.sub.i-(n+k), where k is selectively 1 . . . n. Difference between the first and second products are obtained as (P.sub.1 -P.sub.n+1) . . . (P.sub.n-1 -P.sub.2n), where P.sub.1 =x.sub.i .multidot.x.sub.i-1, P.sub.n-1 =x.sub.i .multidot.x.sub.i-n, P.sub.+1 =x.sub.i-n .

Abstract: The installation comprises a certain number of measuring stations, represed here as three in number referenced respectively 1, 2 and 3, equipped respectively with antennae I.sub.1, I.sub.2, I.sub.3, which are connected by transmission lines L.sub.1, L.sub.2 and L.sub.3 to a central data acquisition unit 4, itself connected to a real time data processing unit 5. The central unit 4 comprises receiving means, means for sorting and associating the data and means for momentary storage of the sorted and associated data.