Camera and method for detecting objects moved through a detection zone

Patent metadata

Field	Value
Publication number	US-11743602-B2
Application number	US-202217833281-A
Country	US
Kind code	B2
Filing date	Jun 6, 2022
Priority date	Jun 7, 2021
Publication date	Aug 29, 2023
Grant date	Aug 29, 2023

Abstract

A camera ( 10 ) is provided for the detection of objects ( 48 ) moved through a detection zone that has an image sensor ( 18 ) for recording image data, a reception optics ( 16 ) having an adjustable diaphragm ( 17 ), and a control and evaluation unit ( 38 ) to read the image data and to set the diaphragm ( 17 ), In this respect, the control and evaluation unit ( 38 ) is furthermore configured to set the diaphragm ( 17 ) per object ( 48 ) such that the object ( 48 ) is recorded in a depth of field range.

First claim

The invention claimed is:

1. A camera for the detection of objects moved through a detection zone, the camera comprising:
an image sensor for recording image data;
reception optics having an adjustable diaphragm, the reception optics having a fixed focal position;
a distance sensor for measuring a distance value from an object; and
a control and evaluation unit to read the image data and to set the diaphragm,
wherein the control and evaluation unit is configured to set the diaphragm per object dependent on the distance value measured from the object such that the object is recorded in a required depth of field range.

2. The camera in accordance with claim 1 ,
wherein the depth of field range is determined from application-specific demands.

3. The camera in accordance with claim 1 ,
wherein the control and evaluation unit is configured to read a code content of a code on the object using the image data.

4. The camera in accordance with claim 3 ,
wherein the object is recorded in the depth of field range when a code can be read from the recorded image data.

5. The camera in accordance with claim 3 ,
wherein the required depth of field range depends on a code type, on a module size, on an exposure, and/or on a decoding process.

6. The camera in accordance with claim 1 ,
wherein the distance sensor is integrated in the camera and/or is configured as an optoelectronic distance sensor in accordance with the principle of the time of flight process.

7. The camera in accordance with claim 1 ,
wherein the control and evaluation unit is further configured to set the diaphragm for the object using a function of the required diaphragm in dependence on the distance of an object.

8. The camera in accordance with claim 1 ,
wherein the control and evaluation unit is further configured for a teaching process in which an object is arranged at a distance, image data are recorded, an image distinction is checked, and the diaphragm is adjusted until a suitable diaphragm setting for this distance has been found.

9. The camera in accordance with claim 1 ,
wherein the fixed focal position is fixed for a maximum object distance.

10. The camera in accordance with claim 1 ,
wherein the control and evaluation unit is further configured to set the diaphragm to a maximum diaphragm aperture for an object at a distance corresponding to the focal position and to increasingly close the diaphragm for different distances.

11. The camera in accordance with claim 10 ,
wherein the different distances are smaller distances.

12. The camera in accordance with claim 1 ,
wherein the control and evaluation unit is configured to set the diaphragm in dependence on a brightness.

13. The camera in accordance with claim 12 ,
wherein the diaphragm is set in dependence on a brightness of the image data.

14. The camera in accordance with claim 1 ,
wherein the diaphragm is installed in the reception optics or is placed onto the reception optics.

15. The camera in accordance with claim 1 ,
that is installed in a stationary manner at a conveying device that guides objects to be detected in a direction of conveying through the detection zone.

16. A method of detecting objects moved through a detection zone comprising:
recording image data with an image sensor through reception optics having an adjustable diaphragm, wherein the reception optics have a fixed focal position;
reading the image data;
measuring a distance value from an object; and
setting the diaphragm per object dependent on the distance value measured from the object such that the object is recorded in a required depth of field range.

17. A camera for the detection of objects moved through a detection zone, the camera comprising:
an image sensor for recording image data;
reception optics having an adjustable diaphragm;
a distance sensor measuring a distance value from an object; and
a control and evaluation unit to read the image data and to set the diaphragm,
wherein the control and evaluation unit is configured to set the diaphragm per object such that the object is recorded in a depth of field range, and
wherein the control and evaluation unit is further configured for a teaching process in which an object is arranged at a distance, image data are recorded, an image distinction is checked, and the diaphragm is adjusted until a suitable diaphragm setting for this distance has been found.

Assignees

• Sick Ag

Inventors

• Müller Romain
• Strohmeier Dirk

Classifications

• H04N23/959 Primary

  by adjusting depth of field during image capture, e.g. maximising or setting range based on scene characteristics · CPC title

• H04N23/671

  in combination with active ranging signals, e.g. using light or sound signals emitted toward objects · CPC title

• G01S17/08 Primary

  for measuring distance only (indirect measurement G01S17/46; active triangulation systems G01S17/48) · CPC title

• G03B7/006 Primary

  setting of both diaphragm and distance (G03B7/02 - G03B7/22 take precedence) · CPC title

• G01S17/894

  Three-dimensional [3D] imaging with simultaneous measurement of time-of-flight at a two-dimensional [2D] array of receiver pixels, e.g. time-of-flight cameras or flash lidar · CPC title