초록 ▼

A method of estimation of the direction of the line of sight comprising forming at least two images representing one and the same portion of the scene (P) at two successive instants using an instrument mounted on a moving carrier, and the determination of the change of orientation of the line of sig

A method of estimation of the direction of the line of sight comprising forming at least two images representing one and the same portion of the scene (P) at two successive instants using an instrument mounted on a moving carrier, and the determination of the change of orientation of the line of sight by matching homologous points (A1, A2) in the two images of the same portion of scene by calculating the angular variations in attitude between the two instants at which the two successive images are obtained and by correcting on the basis of the deviation, between the estimate of the point (A2) homologous in the image provided by a model, and the actual position of the homologous point, and integrating and time filtering pertaining to a sequence of several successive determinations of attitude variations, leading to an estimate of the direction of the line of sight.

대표청구항 ▼

The invention claimed is: 1. Method of restoring the movements of a line of sight (V) in terms of roll, pitch and yaw of an observation instrument during an image sequence, according to which, at least a first and a second image containing one and the same portion of a scene being formed, the first

The invention claimed is: 1. Method of restoring the movements of a line of sight (V) in terms of roll, pitch and yaw of an observation instrument during an image sequence, according to which, at least a first and a second image containing one and the same portion of a scene being formed, the first and the second images being formed over the picture-taking duration [Ti, Tf] on the basis of the observation instrument mounted on a moving carrier, the takes of the first and the second images being offset in time by a substantially constant known value T; Tn being the average instant of acquisition of a chosen image n, n being the indice of an image, n going from i to f, i being the indice of the first image, f being the indice of the last image, T being the temporal deviation between the acquisition of two images; said movements of the line of sight (V) of the observation instrument in the course of the image sequence being determined by at least the following steps:a) a step of selecting several characteristic zones in a first image and matching these zones with homologous zones in the second image, by textural or radiometric analysis, these homologous zones being taken in the vicinity of instants respectively Tn and Tn+T distributed between Ti and Tf in the said images of the same portion of the scene so as to obtain a measurement of the position at the instants respectively Tn and Tn+T of the said homologous zones, or of at least a particular point of these zones, in each of the two images of the said portion,b) a step of determining an image matching model by a geometric modeling of with an optical system; said image matching model giving for any point of a first image shot at the instant Tn, an estimate of the position of its homologous point in a second image shot at the instant Tn+T ; said image matching model being a function of, in particular, the orientation of the line of sight (V) of the instrument at the instant Tn and angular variations of this line of sight (V) between Tn and Tn +T;wherein the first and the second images have been acquired in push-broom mode and wherein the method further comprises the following steps:c) a step of calculating the angular variations of the line of sight (V) of the observation instrument between the instants Tn and Tn+T by adjusting said image matching model, the adjustment of said image matching model consisting in calculating the values of the angular variations which minimize a function of the deviations between the position of the homologous zones of the second image that are predicted by the image matching model, and the position of the homologous zones of the second image as it is matched in step (a), andd) a step of reconstructing the movements of the line of sight (V) over the time horizon [Ti, Tf] by integrating and filtering the angular variations calculated in step (c).