Patent ID: 8098383

Claim:
A method for the optical detection of the position and orientation of an object by means of an optical device comprising at least one first parallelogram (A′B′C′D′) fastened to the object, whose characteristics are known, and having optical means and electronic analysis means to determine the coordinates of the four vertices of the first parallelogram (A′B′C′D′), in an orthonormal frame (R 0 (O, {right arrow over (i)}, {right arrow over (j)},{right arrow over (k)})), having a center (O), said frame comprising a plane (O, {right arrow over (j)},{right arrow over (k)}) parallel to an image plane (Pi), said method comprising: a first step of defining a second reference parallelogram (A 0 B 0 C 0 D 0 ) whose center (O) is the center of the frame (R 0 (O, {right arrow over (i)}, {right arrow over (j)},{right arrow over (k)})), possessing the same characteristics as the first parallelogram (A′B′C′D′), situated in the plane (O, {right arrow over (j)},{right arrow over (k)}) parallel to the image plane (Pi); a second step of defining a transformation under which the first parallelogram (A′B′C′D′) is the image of the second parallelogram (A 0 B 0 C 0 D 0 ), said transformation decomposing into a translation {right arrow over (u)} and a vector rotation r. a third step of determining, through the optical means, a quadrilateral (ABCD), obtained by projecting the first parallelogram (A′B′C′D′) into the image plane (Pi), with nonzero abscissa Xi, in the frame (R 0 ) with center O, along a direction ({right arrow over (i)}) perpendicular to the image plane (Pi), a fourth step of determining: a first point (E) belonging to the image plane (Pi), when it exists, such that the first point (E) is the intersection of the straight lines formed by two opposite sides of the quadrilateral (AB, CD); a second point (F) belonging to the image plane (Pi), when it exists, such that the second point (F) is the intersection of the straight lines formed by the other two sides of the quadrilateral (AC,BD), a first vector ({right arrow over (OE)}), connecting the center of the frame (O) and the first point (E); a second vector ({right arrow over (OF)}), connecting the center of the frame (O) and the second point (F); a fifth step of determining the respective images of the unit vectors ({right arrow over (i)}, {right arrow over (j)},{right arrow over (k)}), defining the frame (R 0 ), by a rotation (r) of the transformation, as a function of the first and second vectors ({right arrow over (OE)}, {right arrow over (OF)}) and of the known characteristics of the second parallelogram (A 0 B 0 C 0 D 0 ); a sixth step of determining a translation ({right arrow over (u)}) of the transformation as a function of the first and second vectors ({right arrow over (OE)}, {right arrow over (OF)}), of the vector connecting the center of the frame (O) to a vertex of the quadrilateral (ABCD) and of the known characteristics of the second parallelogram (A 0 B 0 C 0 D 0 ).