SYSTEMS AND METHODS OF OBJECT MEASUREMENT IN AN AUTOMATED DATA READER

• US 20140028837A1
• Filed: 07/23/2013
• Published: 01/30/2014
• Est. Priority Date: 07/24/2012
• Status: Active Grant

• Current Assignee: Datalogic USA, Inc.
• Original Assignee: Datalogic Adc, Inc. (Datalogic S.p.A.)
• Inventors: Gao, WenLiang, Olmstead, Bryan L., Shearin, Alan
• Granted Patent: US 9,651,363 B2
• Time in Patent Office: Days
• US Class Current: 348/136
• CPC Class Codes: G01B 11/04 specially adapted for measuring length or width of objects while moving
• CPC Class Codes: G01B 11/0608 Height gauges
• CPC Class Codes: G06K 7/10792 Special measures in relation to the object to be scanned
• CPC Class Codes: G06Q 20/20 Point-of-sale [POS] network systems
• CPC Class Codes: G07G 1/0063 with means for detecting the geometric dimensions of the article of which the code is read, such as its size or height, for the verification of the registration
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: H04N 7/18 Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast

Abstract

Systems and methods of determining object dimensions of objects passed through a read zone of an automated data reader are disclosed. A system can include a data reader to read an optical code disposed on the objects, a transport mechanism, an object measurement system to measure dimensions of objects that are transported by the transport mechanism, a light plane generator to project a light plane that produces a light stripe on an object, and a camera to capture image data of objects and a light stripe thereon that can be processed to determine a deviation of a light stripe relative to an optical center within the image data. A deviation from the optical center is used to determine one or more dimensions of the object.

Claims

1. An automated data reading system comprising:

a data reader configured to identify objects as they pass through one or more read zones of the data reader;

a transport mechanism to transport the objects placed thereon through one or more read zones of the data reader, the transport mechanism having a top surface on which the objects are placed and transported, the top surface defining a transport plane, wherein the transport mechanism transports the objects in a scanning direction; and

an object measurement system to measure dimensions of objects that are transported by the transport mechanism through the data reader, the object measurement system comprising;

a light plane generator disposed above the transport mechanism and operable to project a light plane vertically downward toward the transport mechanism, the light plane projected perpendicular to the transport plane and to the scanning direction, wherein the light plane produces a light stripe where the light plane strikes an object;

a camera disposed above the transport mechanism and offset from the light plane generator, the camera comprising an imager and a lens and having a field of view (FOV) directed downward toward the transport mechanism and at an angle to the light plane, the camera configured to capture image data of an object as the object passes through the light plane,

wherein a position of the light stripe within the image data is used to calculate a measurement of one or more dimensions of the object.

2. The system of claim 1, wherein the light plane generator is a first light plane generator, wherein the object measurement system further comprises:

a second light plane generator disposed above the transport mechanism and operable to project a second light plane vertically downward toward the transport mechanism, the second light plane oriented perpendicular to the transport plane and to the scanning direction and parallel to the light plane of the first light plane generator, wherein the second light plane produces a second light stripe where the second light plane strikes an object,

wherein the camera is configured to capture image data of an object as the object passes through the second light plane, and wherein a position of the second light stripe within the image data is used to determine a measurement of one or more dimensions of the object.

3. The system of claim 2, wherein a maximum measuring height at the first light plane is higher than a maximum measuring height at the second light plane.

4. The system of claim 2, wherein shorter objects are measured with greater accuracy from image data of the second light stripe than from image data of the first light stripe.

5. The system of claim 2, wherein a height dimension of the object is calculated based on a vertical deviation of the position of one of the first light stripe and the second light stripe from a position of an optical center in the image data.

6. The system of claim 5, wherein the measurement of the height dimension Z of the object is:

7. The system of claim 2, wherein one or more horizontal deviations of the position of one of the light stripe and the second light stripe from the optical center are used to calculate a width dimension of the object.

8. The system of claim 7, wherein calculating the width dimension of the object includes using triangulation based on a determined height dimension of the object.

9. The system of claim 7, wherein the measurement of the width dimension X of the object is calculated by determining a distance between two physical coordinates X_phy, wherein each physical coordinate X_phy is calculated using the equation:

10. The system of claim 2, wherein a time period during which the position of the light stripe is deviated from a base position and a transport rate are used to calculate a length dimension of the object.

11. The system of claim 10, wherein the measurement of the length dimension Y of the object is:

12. The system of claim 2, wherein measurement of one or more dimensions of the object comprises measuring a dimension of the object along a single axis.

13. The system of claim 2, wherein measurement of one or more dimensions of the object comprises measuring two dimensions of the object along two transverse axes.

14. The system of claim 2, wherein measurement of one or more dimensions of the object comprises measuring three dimensions of the object along three transverse axes.

15. The system of claim 2, wherein a first edge of the FOV of the camera captures an intersection of the light plane and the transport plane and a second edge of the FOV of the camera intersects the light plane at a point above the transport plane and intersects the second light plane at a lower point above the transport plane.

16. The system of claim 2, wherein the first and second light plane generators each comprise an infrared (IR) laser and a diverging lens, the IR laser and lens being configured to generate a fan of vertical rays from the diverging lens to a plurality of points spaced across the transport plane, the rays disposed in a plane orthogonal to the scanning direction.

17. The system of claim 2, wherein the object measurement system further comprises a processor configured to receive image data captured by the imager of the camera of the object measurement system to calculate the measurement of the one or more dimensions of the object.

18. The system of claim 17, wherein the processor is further configured to:

compare the measurement of the one or more dimensions of the object to dimension data corresponding to an object successfully identified by a data reader as the object passed through the one or more read zones of the data reader, wherein the comparison determines whether the object has one or more dimensions that correspond to the dimension data associated with the successfully identified object.

19. A method for measuring object dimensions in an automated data reading system having a transport plane on which objects are moved through the data reading system, the method comprising:

generating a first light plane from a first position above the transport plane of the automated data reading system, the first light plane being generated to project vertically downward toward the transport plane and oriented perpendicular to the transport plane, wherein a first light stripe is produced on an object being moved on the transport plane where the first light plane strikes the object;

capturing first image data of the object as the object passes through the first light plane, wherein the first image data is captured by a camera from a second position above the transport plane and offset from the first position, the camera having a field of view (FOV) directed downward toward the plane and angled toward the first light plane;

processing the first image data captured by the camera to determine a position of the first light stripe within the image data;

determining a deviation of the position of the first light stripe within the first image data; and

calculating one or more dimensions of the object using the deviation.

20. The method of claim 19, wherein capturing the first image data includes:

capturing a first image including image data of the object and image data of the first light stripe on the object;

capturing a second image including image data of the object with the first light plane generator turned off.

21. The method of claim 20, further comprising:

subtracting the second image from the first image to generate a high contrast image including image data of the first light stripe and not including a least a portion of background image data of the first image and the second image.

22. The method of claim 19, further comprising:

generating a second light plane from a third position above the transport plane, wherein the second light plane is generated to project vertically downward toward the transport plane and oriented perpendicular to the transport plane and approximately parallel to the first light plane, wherein a second light stripe is produced on an object being moved on the transport plane where the second light plane strikes the object;

capturing second image data of the object as the object passes through the second light plane, wherein the second image data is captured by the camera from the second position above the transport plane and offset from the third position, the FOV of the camera directed downward toward the transport plane and angled toward the second light plane;

processing the second image data captured by the camera to determine a position of the second light stripe within the image data;

determining a second deviation of the position of the second light stripe within the second image data; and

calculating one or more dimensions of the object using the second deviation.

23. The method of claim 22, further comprising:

subtracting the second image data from the first image data to generate a first high contrast image from the first image data, the first high contrast image including image data of the first light stripe and not including a least a portion of background image data of the first image,

wherein processing the first image data comprises processing the first high contrast image.

24. The method of claim 22, further comprising:

subtracting the first image data from the second image data to generate a second high contrast image from the second image data, the second high contrast image including image data of the second light stripe and not including a least a portion of background image data of the second image,

wherein processing the second image data comprises processing the second high contrast image.

25. A system for measuring object dimensions in an automated optical code reader, the system comprising:

a first laser plane generator operable to project a first laser plane vertically downward toward a transport plane on which objects are moved through the automated optical code reader, the first laser plane oriented perpendicular to the transport plane, wherein the first laser plane produces a first laser stripe where the first laser plane strikes an object;

a second laser plane generator operable to project a second laser plane vertically downward toward the transport plane, the second laser plane oriented perpendicular to the transport plane and parallel to the first laser plane, wherein the second laser plane produces a second laser stripe where the second laser plane strikes an object;

a camera disposed above the transport plane and offset from the first laser plane generator and the second laser plane generator, the camera comprising an imager and a lens and having a field of view (FOV) directed downward toward the transport plane and at an angle to the first laser plane and to the second laser plane, the camera configured to capture first image data of an object as the object passes through the first laser plane and to capture second image data of the object as the object passes through the second laser plane, wherein a position of one of the first laser stripe within the first image data and the second laser strip within the second image data, relative to a position of an optical center within the first image data and the second image data, is used to determine one or more dimensions of the object.