Thales

Alain Simon

Etienne Payot

Paul Thibout

Jerome Fournier

Frédéric Le Gusquet

Gilles Henaff

Jérôme Fournier

A method for estimating the bearing of an optronic system in a geographical reference frame, the optronic system being situated at a first position and denoted first optronic system is provided. It comprises the following steps: defining a collaborative configuration, by way of the first optronic system and of at least one other optronic system, the optronic systems being respectively situated at separate positions and equipped with means for communication with one another, and with acquisition devices, acquiring, in a scene, one or more objects common to the optronic systems, the direction of orientation between each optronic system and each object being unknown, determining two positions from among those of the optronic systems, for at least one common object: measuring the relative angle by way of a relative angle measurement device fitted to the first optronic system, measuring the elevation of the object by way of an elevation measurement device fitted to the first optronic system, performing additional measurements by way of each other optronic system, with the two positions and the measurements constituting observations, communication, by the other optronic system(s) to the first optronic system, of the observations that it does not have, on the basis of the observations, estimation, by the first optronic system, of the bearing of the first optronic system.

Method of estimating a direction of absolute orientation of an optronic system

The invention relates to a method of determining the absolute direction of an object of a scene (), with a predetermined desired performance. It comprises a learning phase and an online operation phase, the learning phase comprising the following steps: acquisition by circular scanning by means of a first optronic imaging device of determined fixed position, of a series of partially overlapping optronic images (), including an image or several images of the scene (step A), automatic extraction from the images, of descriptors defined by their image coordinates and their radiometric characteristics, with at least one descriptor of unknown direction in each overlap () of images (step B), from the descriptors extracted from the overlaps between images, automatic estimation of the mutual relative rotation of the images and mapping of the descriptors extracted from the overlaps (step C), identification in the images, of at least one known reference geographic direction () of precision compatible with the desired performance, and determination of the image coordinates of each reference (step D), from the descriptors extracted from the overlaps and mapped, the direction and the image coordinates of each reference, automatic estimation of the attitude of each image, called fine registration step (step E), from the attitude of each image, the position and internal parameters of the first imaging device, and the image coordinates of each descriptor, computation of the absolute directions of the descriptors according to a predetermined model of image capture of the imaging device (step F), the online operation phase comprising the following steps: acquisition of at least one image of the object called current image (), from a second imaging device of determined fixed position (step A), extraction of descriptors from each current image (step B), mapping of the descriptors of each current image with the descriptors whose absolute direction was calculated in the learning phase, to determine the absolute direction of the descriptors of each current image (step C), from the absolute directions of the descriptors of each current image, estimation of the attitude of each current image (step D), from the image coordinates of the object in each current image, the attitude of each current image, the position and predetermined internal parameters of the second imaging device, computation of the absolute direction of the object according to a predetermined model of image capture of each current image (step E).

Method of determining a direction of an object on the basis of an image of the object

A method for formulating a knowledge database of object images acquired by an imaging device furnished with a sensor, including defining N classes each including a set of objects represented by a label and a set of characteristics, learning decision rules associated with these classes, definition of K contextual information cues regarding image background f, with k varying from 1 to K and K&#x3e;1, association of one of these information cues regarding image background fwith each object, allotting of the objects into M new classes, with N&#x3c;M&#x2266;K&#xd7;N, each including a set of objects represented by a new label including an old label and one of said information cues regarding image background fand the set of characteristics of these objects, definition for each background fof a subset Qof these M classes associated with this image background, learning of decision rules for each of these subsets Q.

Method for classifying objects in an imaging surveillance system

A method for geo-referencing an area by an imaging optronics system which comprises acquiring M successive images by a detector, the imaged area being distributed between these M images, with M&#x2267;1. It comprises: measuring P distances d, d, . . . , dbetween the system and P points of the area, called range-found points, with P&#x2267;3, distributed in K of said images with 1&#x2266;K&#x2266;M; acquiring the positioning x, y, zof the detector at acquisition of the M images; measuring the attitude &#x3c6;, &#x3b8;, &#x3c8;of the detector at acquisition of the M images; acquiring the coordinates in these K images of image points (p, q), (p, q), . . . , (p, q) corresponding to the P range-found points; and estimating the parameters of exposure conditions x, y, z, &#x3c8;, &#x3b8;, &#x3c6;corresponding to the M images as a function of positionings, of attitudes, distances and coordinates of the image points, to correct errors on the parameters x, y, z, &#x3c8;, &#x3b8;, &#x3c6;of each of the M images.

Method for geo-referencing an imaged area

A method for calibrating measurement instruments of an optronic system in motion, with positions P, P, . . . , P, . . . , comprises: a device for acquiring images of a scene comprising a fixed object G; and means for tracking the fixed object Gduring the acquisition of these images; means for obtaining the positions P, P, . . . ; at least one instrument for measuring the distance and/or an instrument for measuring angles of orientation and/or of attitude between this measurement instrument and the fixed object G, according to a line of sight LoS. It comprises the following steps: acquisition at instants t, t, . . . of at least two images, each image being acquired on the basis of different positions P, P, . . . of the system, the fixed object Gbeing sighted in each image, but its position being unknown; acquisition at the instants t', t&#x2032;, . . . of measurements of distance and/or of angle; synchronization of the measurements of distance and/or of angle with the positions P, P, . . . established at instants t, t, . . . ; estimation of the measurement defects which minimize the dispersion of at least two points of intersection Gbetween the LoS at the position Pand the LoS at the position P, as a function of said measurements and of the known positions P, Pof the system.

Method for calibrating a measurement instrument of an optronic system

A method for geolocating a fixed non-cooperating object by means of an embedded system onboard a mobile platform, equipped with distance acquisition means for acquiring the distance between the object and the system, and position acquisition means for acquiring the position of the system, includes acquiring two distance measurements of the object relative to two distinct positions of the system, thus defining two object position-distance pairs, the positions being those of the system and being obtained by the position acquisition means, and the distances being obtained by the distance acquisition means. The method also includes acquiring at least one other object position-distance pair, and calculating the geolocation of the object from these object position-distance pairs.

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Les Mesnuls, France

Alain Simon