Dimensioning Apparatus and Method

• US 20170150129A1
• Filed: 10/24/2016
• Published: 05/25/2017
• Est. Priority Date: 11/23/2015
• Status: Abandoned Application

• Current Assignee: Chicago Measurement LLC
• Original Assignee: Chicago Measurement LLC
• Inventors: PANGRAZIO, JOHN GREGORY
• Application Number:
  US15/332,128
• Publication Number:
  US 20170150129A1
• Time in Patent Office: Days
• CPC Class Codes: G06T 2207/10028 Range image; Depth image; 3D point clouds
• CPC Class Codes: G06T 2207/30164 Workpiece; Machine component
• CPC Class Codes: G06T 7/32 using correlation-based methods
• CPC Class Codes: G06T 7/593 from stereo images
• CPC Class Codes: H04N 13/156 Mixing image signals
• CPC Class Codes: H04N 13/239 using two 2D image sensors having a relative position equal to or related to the interocular distance H04N13/243 takes precedence
• CPC Class Codes: H04N 13/243 using three or more 2D image sensors
• CPC Class Codes: H04N 13/246 Calibration of cameras
• CPC Class Codes: H04N 13/282 for generating image signals corresponding to three or more geometrical viewpoints, e.g. multi-view systems
• CPC Class Codes: H04N 13/296 Synchronisation thereof; Control thereof
• CPC Class Codes: H04N 23/90 Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums

Abstract

An apparatus and method enable a workpiece carried on a transportation device to be dimensioned. The apparatus includes a plurality of camera pairs that are situated about a detection zone, and each of the camera pairs simultaneously capture an image of the workpiece. For each camera pair, the images are subjected to a reconciliation operation to obtain a point cloud that includes a plurality of points in three dimensional space from the perspective of that camera pair. The points represent points on the surface of the workpiece or the transportation device or another surface. The point clouds are transformed into transformed points in three dimensional space from the perspective of a pre-established origin of the dimensioning apparatus. The transformed points are combined together to obtain a combined point cloud that is used to generate a characterization of the workpiece from which the dimensions of the workpiece can be obtained.

Claims

1. A method of employing a dimensioning apparatus to generate a characterization of a workpiece that is carried on a transportation device and that is situated in a detection zone of the dimensioning apparatus, the dimensioning apparatus comprising a plurality of detection devices, the method comprising:

substantially simultaneously capturing a representation of the workpiece with each of the plurality of detection devices;

for each detection device, employing the representation therefrom to obtain a point cloud that comprises a plurality of points in three-dimensional space from the perspective of the detection device;

transforming the point cloud of at least one detection device into a transformed point cloud that comprises a plurality of transformed points in three-dimensional space from the perspective of a pre-established origin of the dimensioning apparatus that is different from the perspective of the at least one detection device;

combining together the transformed point cloud and another point cloud from another detection device that comprises another plurality of points in three-dimensional space from the perspective of the pre-established origin to obtain a combined point cloud, the at least one detection device being different from the another detection device; and

employing the combined point cloud to generate the characterization.

2. The method of claim 1 wherein the combining comprises moving one of the transformed point cloud and the another point cloud with respect to the other until a predetermined level of correspondence is achieved between the transformed point cloud and the another point cloud.

3. The method of claim 1 wherein at least some of the detection devices of the plurality of detection devices each comprise a pair of sensing elements that each have an operational direction, the operational directions of the pair of sensing elements being oriented generally parallel with one another and toward the detection zone, wherein the capturing comprises capturing substantially simultaneously with each pair of sensing elements a pair of representations of the workpiece, and further comprising subjecting each pair of representations to a reconciliation operation to obtain as the point cloud a point cloud that comprises a plurality of points in three-dimensional space from the perspective of the pair of sensing elements.

4. The method of claim 3, further comprising:

prior to the capturing, subjecting the pair of sensing elements to a calibration operation to generate a number of reconciliation values; and

employing at least some of the reconciliation values of the number of reconciliation values in the subjecting of each pair of representations to the reconciliation operation.

5. The method of claim 4 wherein at least one pair of sensing elements is a pair of cameras each having a sensor, wherein the pair of representations from the at least one pair of sensing elements is a pair of images each comprising a plurality of pixels each having a brightness value, and wherein the subjecting of the pair of representations to the reconciliation operation comprises identifying in a first image of the pair of images a first pair of adjacent pixels having a first difference in brightness values that exceeds a predetermined value.

6. The method of claim 5, further comprising:

identifying in a second image of the pair of images a second pair of adjacent pixels having a second difference in brightness values that is within a predetermined threshold of the first difference;

based at least in part upon the identifying, determining that a pixel of the first pair of pixels and another pixel of the second pair of pixels represent the same location on a surface of the workpiece; and

assigning to one of the pixel and the another pixel a set of coordinates in three dimensional space having three values, two of the three values being based upon a location of the one of the pixel and the another pixel on a sensor of the camera of the pair of cameras that captured it.

7. The method of claim 6 wherein the cameras of the pair of the cameras are horizontally spaced apart, wherein the pixel is situated at a first horizontal distance from a first origin on the sensor of the camera of the pair of cameras that captured it, and wherein the another pixel is situated at a second horizontal distance from a second origin on the sensor of the camera of the pair of cameras that captured it, and further comprising assigning the third of the three values based at least in part upon a difference between the first horizontal distance and the second horizontal distance.

8. A dimensioning apparatus having a detection zone and being structured to generate a characterization of a workpiece that is carried on a transportation device within the detection zone, the dimensioning apparatus comprising:

a plurality of detection devices each having an operational direction that is oriented generally toward the detection zone;

a computer system comprising a processor and a storage, the computer system further comprising a number of routines that are stored in the storage and that are executable on the processor to cause the dimensioning apparatus to perform operations comprising;

substantially simultaneously capturing a representation of the workpiece with each of the plurality of detection devices;

for each detection device, employing the representation therefrom to obtain a point cloud that comprises a plurality of points in three-dimensional space from the perspective of the detection device;

transforming the point cloud of at least one detection device into a transformed point cloud that comprises a plurality of transformed points in three-dimensional space from the perspective of a pre-established origin of the dimensioning apparatus that is different from the perspective of the at least one detection device;

combining together the transformed point cloud and another point cloud from another detection device that comprises another plurality of points in three-dimensional space from the perspective of the pre-established origin to obtain a combined point cloud, the at least one detection device being different from the another detection device; and

employing the combined point cloud to generate the characterization.

9. The dimensioning apparatus of claim 8 wherein the combining comprises moving one of the transformed point cloud and the another point cloud with respect to the other until a predetermined level of correspondence is achieved between the transformed point cloud and the another point cloud.

10. The dimensioning apparatus of claim 8 wherein at least some of the detection devices of the plurality of detection devices each comprise a pair of sensing elements that each have an operational direction, the operational directions of the pair of sensing elements being oriented generally parallel with one another and toward the detection zone, wherein the capturing comprises capturing substantially simultaneously with each pair of sensing elements a pair of representations of the workpiece, and wherein the operations further comprise subjecting each pair of representations to a reconciliation operation to obtain as the point cloud a point cloud that comprises a plurality of points in three-dimensional space from the perspective of the pair of sensing elements.

11. The dimensioning apparatus of claim 10 wherein the operations further comprise:

prior to the capturing, subjecting the pair of sensing elements to a calibration operation to generate a number of reconciliation values; and

employing at least some of the reconciliation values of the number of reconciliation values in the subjecting of each pair of representations to the reconciliation operation.

12. The dimensioning apparatus of claim 11 wherein at least one pair of sensing elements is a pair of cameras each having a sensor, wherein the pair of representations from the at least one pair of sensing elements is a pair of images each comprising a plurality of pixels each having a brightness value, and wherein the subjecting of the pair of representations to the reconciliation operation comprises identifying in a first image of the pair of images a first pair of adjacent pixels having a first difference in brightness values that exceeds a predetermined value.

13. The dimensioning apparatus of claim 12 wherein the operations further comprise:

identifying in a second image of the pair of images a second pair of adjacent pixels having a second difference in brightness values that is within a predetermined threshold of the first difference;

based at least in part upon the identifying, determining that a pixel of the first pair of pixels and another pixel of the second pair of pixels represent the same location on a surface of the workpiece; and

assigning to one of the pixel and the another pixel a set of coordinates in three dimensional space having three values, two of the three values being based upon a location of the one of the pixel and the another pixel on a sensor of the camera of the pair of cameras that captured it.

14. The dimensioning apparatus of claim 13 wherein the cameras of the pair of the cameras are horizontally spaced apart, wherein the pixel is situated at a first horizontal distance from a first origin on the sensor of the camera of the pair of cameras that captured it, and wherein the another pixel is situated at a second horizontal distance from a second origin on the sensor of the camera of the pair of cameras that captured it, and wherein the operations further comprise assigning the third of the three values based at least in part upon a difference between the first horizontal distance and the second horizontal distance.

15. The dimensioning apparatus of claim 10 wherein a first detection device of the plurality of detection devices is oriented such that the operational directions of its pair of sensing elements are situated in a first direction generally toward the detection zone, and wherein a second detection device of the plurality of detection devices is oriented such that the operational directions of its pair of sensing elements are situated in a second direction generally toward the detection zone, the first and second directions being different from one another.