METHOD OF IMAGING AN OBJECT FOR TRACKING AND DOCUMENTATION IN TRANSPORTATION AND STORAGE

Abstract

In a method of operating a dimensioning system with a plurality of laser scanners, a processor controls the operations of the scanners and processes the scanner signals, and further with memory for storing data delivered by the processor, the data acquired by the dimensioning system in its regular mode of operation are used to construct a three-dimensional model of surface points of the object including spatial coordinates and image intensity for each surface point. The three-dimensional model is stored in the memory. Based on the three-dimensional model, two-dimensional images from any desired viewing angle that was exposed to the scanner rays can be produced on demand to document the appearance of the object at the time the scan was taken.

Claims

1. A system for dimensioning an object, comprising a plurality of laser scanners, each of which comprises: an emitter of a collimated beam of modulated laser radiation; a dynamic beam deflector to move the collimated beam in a sweeping motion over the object; and a radiation sensor, for receiving the radiation reflected from the object and translating the reflected radiation into an electrical signal, a processor, adapted with software instructions to control the operation of each of the laser scanners, to receive and process the electrical signals produced by the radiation sensors, and to perform the following functions: at discrete points in time, calculates a distance value based on the time delay or phase shift value between emitted and received radiation, based on the spatial direction of the beam, the distance value, and the intensity at each individual point in time, assembles a three-dimensional model of surface points of the object including the intensity value associated with each surface point, and storage means, in communication with the processor, to receive and store the three-dimensional model, such that, on demand, the three-dimensional model is used to produce two-dimensional images from any desired viewing angle that was exposed to the scanner rays to document the appearance of the object at the time the scan was taken.

2. A method of producing an image of an object based on data acquired by a dimensioning system which, in a regular mode of operation, generates a dimensional weight for the object, the dimensioning system comprising a plurality of laser scanners, each of which contains an emitter of a collimated beam of modulated laser radiation, a dynamic beam deflector to move the collimated beam in a sweeping motion over the object, and a radiation sensor arranged to receive the radiation reflected from the object and convert the radiation into an electrical signal, a processor adapted to control the operation of the scanners, to receive and process the electrical signals produced by the radiation sensors, and to execute software instructions configured on the processor to calculate distance values, at discrete points in time, based on the time delay or phase shift value between emitted and received radiation and based on the spatial direction of the beam, the distance value, and the intensity at each individual point in time, calculate a dimensional weight as the product of a length, a height, a width and a predetermined density factor, wherein the method comprises the steps of: assembling a three-dimensional model of surface points of the object including the intensity value associated with each surface point, and storing the three-dimensional model in a memory means, wherein the three-dimensional model is available to produce, on demand, two-dimensional images from any desired viewing angle that was exposed to the scanner rays to document the appearance of the object at the time the scan was taken.

3. The method of claim 2, comprising the further step of: removing from the three-dimensional model any surface point data that are not part of the object of interest.

4. The method of claim 2, wherein the recording of the three-dimensional model takes place every time the object is subjected to a dimensioning process.

5. The method of claim 3, wherein a time stamp is added to each recording to allow the object and its condition to be tracked over time.

6. The method of claim 5, wherein time-stamped two-dimensional images of the object from a desired viewing angle that was exposed to the scanner rays are used to document damage suffered by the object in transportation or storage and determine a time interval when the damage occurred.

7. The method of claim 5, wherein the time-stamped two-dimensional images of the object from a desired viewing angle that was exposed to the scanner rays are used to document the presence of the object at different stages of its transportation or storage and determine a point after which a loss of the object occurred.

8. The method of claim 2, wherein the laser scanners are arranged in fixed positions and the object is at rest during the scan.

9. The method of claim 2, wherein the laser scanners are arranged in fixed positions and the object is in motion during the scan.

10. The method of claim 9, wherein the object is moving on a conveyor belt during the scan.

11. The method of claim 9, wherein the object is being moved by a forklift during the scan.

12. The method of claim 2, wherein the object is at rest during the scan and the laser scanners are moved over the object in a controlled manner.

13. The method of claim 2, wherein the dimensioning system comprises a reader device to register an identification code carried by the object and assign said identification code to the three-dimensional model and to two-dimensional images that are made on the basis of the three-dimensional model.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In the following, the invention will be explained in more detail through examples and references to the attached drawings, wherein

[0040] FIG. 1 illustrates an example for the sweep action of one of the laser scanners used to carry out the method;

[0041] FIG. 2 illustrates a scanner arrangement of a dimensioning system used to scan an object that is at rest during the time period when the scanning takes place;

[0042] FIG. 3 illustrates a scanner arrangement of a dimensioning system used to scan objects travelling on a conveyor belt;

[0043] FIG. 4 illustrates a scanner arrangement of a dimensioning system used to scan objects on a forklift truck in motion; and

[0044] FIG. 5 represents a flowchart of the method according to the invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

[0045] FIG. 1 schematically illustrates a laser scanner 1 of a type that can be used to carry out the method of the present invention. Its principal components are an emitter 2 of a collimated beam 3 of modulated laser radiation, a dynamic beam deflector 4, 5 to move the collimated beam 3 in fan-shaped sweeps 6 over the object 7 (wherein the latter can be at rest or in motion), and a radiation sensor 8 (arranged here in a combined emitter/receiver unit 2, 8) to receive the radiation reflected from the object 7 and convert it into an electrical signal.

[0046] After leaving the emitter 2, the laser beam 3 meets the hexagonal mirror prism 4 which in the arrangement of FIG. 1 rotates about a vertical axis 9 and causes the laser beam 3 to perform continuous fan-like sweeps in a horizontal plane. A second deflector 5, here in the form of a planar mirror 5 swiveling about a horizontal axis 10 deflects the sweeping laser beam 3 into the area of the object 7. As a result of the swivel movement of mirror 5, the reflected sweep 11 of the laser beam 3 likewise swivels back and forth, so that a surface of an object 7 that is exposed to the combined sweep and swivel movement of the laser beam 3 can be captured by the scan. However, it should be noted that the deflector arrangement 4, 5 as well the combined sweep/swivel motion described and illustrated here are intended only as a practical example of a scanner arrangement and are not to be interpreted as limitations of the invention.

[0047] FIG. 2 schematically shows a dimensioning system 20 with four scanners 21 of the type illustrated in FIG. 1. The scanners 21 can be mounted for example on the ceiling, aiming at an area where loaded pallets 22 or other cargo objects are temporarily set down for scanning and dimensioning. The overlapping scan data collected by the four scanners 21 are processed by a computer and assembled into a three-dimensional virtual model of the cargo object.

[0048] FIG. 3 illustrates a dimensioning system 30 for packages or other objects moving on a conveyor belt 33. Two scanners 31 are mounted on a yoke-shaped frame 34 in a so-called dual-head arrangement. As the conveyor belt 33 moves substantially transverse to the fan-like sweeps of the scanners 31, it is possible to perform the dimensioning by using scanners of a type without the swiveling second deflector 5 (see FIG. 1). The successive planar sweeps of the laser beams intercept the moving object surface along a series of parallel scan lines, so that for dimensioning purposes, the entire object can be covered without superimposing a swivel movement to the fan-like sweep of the scanner beam.

[0049] FIG. 4 shows a dimensioning system 40 arranged in a warehouse along a path 45 passed by a forklift truck 44. Four scanners 41a, 41b, 41c, 41d are mounted in different positions along the path 45 of the forklift truck. The scanners 41b and 41d are arranged on opposite sides of the path 45, for example suspended from the warehouse ceiling, and are forming a dual-head arrangement analogous to the two scanners 31 in the dimensioning system 30 of FIG. 3. The scanner 41c in cooperation with the scanner 41b serves to measure the speed and direction of the forklift truck 44. The scanner 41a is mounted on one side of the path 45 close to the warehouse floor and serves to measure the height of the pallet and cargo carried by the forklift truck 44. The scan information, including the intensity values, collected by the dimensioning system 40 serves to establish the three-dimensional model data for the truck and cargo. Using state-of-the-art image-processing techniques, the forklift truck as well as any of the warehouse surroundings recorded by the scanners can be removed from the three-dimensional model at any stage before a two-dimensional image is issued.

[0050] Finally, FIG. 5 delineates the method of the invention in the form of a flowchart, recapitulating the essential steps which have been covered in the description as well as in the claims.

[0051] Although the invention has been described by presenting several examples demonstrating the practice of the method in a transportation and logistics environment, it is considered evident that numerous further variants could be created based on the teachings of the present invention, for example by adding one or more scanners to any one of the illustrated dimensioning systems 20, 30, 40 shown in FIGS. 2 to 4 in order to better capture the surfaces of more complicated objects, or by combining features of the individual embodiments with each other and/or by interchanging individual functional units between the embodiments.