| 摘要 |
1. A system for digitally producing moving pictures of identical targets which are to be inserted into a landscape picture, comprising among others an insertion device (I), a landscape picture generator (GI), a digital/analog signal converter (CDA), a visualisation device (V), memory means (MS), computation means (EC) and memorisation means (EM1 to EMn), characterised in that a set of n digital model pictures are arranged in the memory means in the form of m groups of first digital data, each model picture corresponding to a particular attitude of the model and being assimilated to a set of light elements disposed according to a first square pattern (1) limited by a model picture contour which is rectangular and circumscribes the contour of the considered target, each set of first digital data comprising the number of lines (N), the number of elements per line (M), the luminance values of the elements of the first square pattern ; the target being supposed to be situated for each picture at a reference distance away from the observer and seen by him through an adjusted telescope having a reference magnifying power ; that the computation means define the predetermined itineries of the targets which are respectively constituted by broken lines made up of joined segments, the attitude of the target remaining constant over the length of each segment and a model picture corresponding to each of them that the computation means produce, during n successive periods (Tc) included in the picture scanning period (Tv) of the visualisation device, n sets of second digital data representing n target pictures, then, at the end of period (Tv), transfer the second digital data to n memorisation means, the target pictures being assimilated to se s of light elements disposed according to a second square pattern (fig. 3) identical to the first one but limited by a contour which is homothetic to the contour of the model picture according to a first homothetic ratio equal to 1/k, the value k depending on the one hand on the ratio between the real distance of the simulated target and the reference distance, and on the other hand on the ratio between the real magnifying power of the telescope and the reference magnifying power ; the determination of each second digital data, representing the brightness of a target picture element, consisting in superposing to the first square pattern, belonging to the model picture associated to the considered target picture, a third square pattern (3) which is homothetic to the second square pattern according to a second homothetic ratio equal to k and limited by a contour which is identical to the contour of the model picture, and in rendering the brightness of each element of the second square pattern equal to the sum of the brightness, divided by k**2 , of the elements and fractions of elements of the first square pattern which are delimited by the particular element of the third square pattern, homologeous to the considered second square pattern according to a second homothetic ratio, and that the n memorisation means (EM1 to EMn) receive at each picture scanning period (Tv) from the computation means and after the computation of the n target pictures n sets of second digital data and furnish to the digital/analog converter, at the scan rhythm of the visualisation device and during the insertion time intervals corresponding to the determined places in the landscape picture for the target pictures, n other sets of second digital data which had been received during the preceding picture scanning period, the resulting analog signal being transmitted to the insertion device (I). |
