Method and apparatus for inspection of a subject article
A sensing apparatus including a plurality of sensing units having an energy source for transmitting a beam of electromagnetic radiation through a subject article and a detector for receiving the beam emerging from the subject article, and a controller, in which the detectors are arranged in a dispersed configuration, in which the sensing units include multiple groups. The controller sends a first activation signal to an individual group and a second activation signal to the next group at separate times and subsequent signals to further groups. In the dispersed configuration each detector of each group is spaced from each other detector of each other group a greater distance than it is spaced from the nearest detector of the next sequential group.
1. A method for inspection of a subject article, comprising the steps of:
providing a plurality of beam trajectories for beams of electromagnetic radiation, said plurality of beam trajectories being arranged in a dispersed configuration that is decomposable into a partition of groups of beam trajectories, each of said groups including at least one beam trajectory, distances between said beam trajectories in groups including more than one beam trajectory being not less than a predetermined value which is greater than at least one of the distances between said beam trajectories in said plurality of beam trajectories; and
successively activating each of said groups so as to cause said beams of electromagnetic radiation to be transmitted along said beam trajectories of said group while positioning said subject article in said plurality of beam trajectories, and sensing the electromagnetic radiation from each of said beams that have been transmitted through or reflected from said subject article.
2. The method according to claim 1 , wherein the positioning includes moving the subject article across said plurality of beam trajectories.
3. The method according to claim 1 , further including establishing a correspondence between each of said sensed electromagnetic radiation from each of said beams that have been transmitted through or reflected from said subject article and a corresponding location of said subject article where said electromagnetic radiation has been reflected from or transmitted through.
4. The method according to claim 3 , including converting said correspondence between said locations and said electromagnetic radiation which has been transmitted through or reflected from said subject article into a representation by pixels on a screen.
5. The method according to claim 1 , wherein all of the groups have a same number of beam trajectories.
6. The method according to claim 1 , including creating at least one of said groups of beam trajectories by a translational shift of another one of said groups.
7. The method according to claim 1 , including selecting said predetermined value so as to avoid interference between said beams on said beam trajectories.
8. An apparatus for inspection of a subject article, comprising:
means for transmitting a plurality of beams of electromagnetic radiation along a plurality of beam trajectories, said beam trajectories being arranged in a dispersed configuration that is decomposable into a partition of groups of beam trajectories, each of said groups including at least one beam trajectory, distances between said beam trajectories in groups including more than one beam trajectory being not less than a predetermined value which is greater than at least one of the distances between said beam trajectories in said plurality of beam trajectories;
means for positioning said subject article in said plurality of beam trajectories; and
means for sensing the electromagnetic radiation of each of said beams that has been transmitted through or reflected from said subject article.
9. The apparatus according to claim 8 , wherein said positioning means includes means for moving said subject article across said plurality of beam trajectories.
10. The apparatus according to claim 8 , wherein said beam trajectories are parallel to one another in a spatial region that is provided for positioning said subject article in said plurality of beam trajectories.
11. The apparatus according to claim 10 , wherein said beam trajectories, in said region where the beam trajectories are parallel to one another, are arranged in an array of parallel rows and columns, said rows extending transverse to a direction of motion of said subject article and being equally spaced along said direction of motion, said beam trajectories being equally spaced in said rows.
12. The apparatus according to claim 11 , wherein said beam trajectories in each of said rows are laterally offset from the beam trajectories in a neighboring row by a distance equal to a distance between the beam trajectories in each row divided by a number of rows.
13. The apparatus according to claim 11 , wherein in each of said groups a distance between the beam trajectories in a direction of the rows is equal to or greater than twice the spacing between the beam trajectories in each row and a distance in an orthogonal direction is equal to or greater than twice the spacing between the rows.
14. The apparatus according to claim 8 , wherein said transmitting means includes a plurality of energy sources each adapted to supply a beam of electromagnetic radiation to one of said beam trajectories, and a plurality of sensors, each adapted to detect the electromagnetic radiation from one of said beams transmitted through or reflected from said subject article.
15. The apparatus according to claim 14 , wherein the energy sources are near infrared lasers.
16. The apparatus according to claim 8 , further comprising:
means for successively activating each of said groups so as to cause said beams of electromagnetic radiation to be transmitted along said beam trajectories in each of said groups, with said subject article in position across said plurality of beam trajectories.
17. The method according to claim 8 , wherein said predetermined value is such so as to avoid interference between said beams on said beam trajectories.