Device and method for safeguarding an automatically operating machine

Patent metadata

Field	Value
Publication number	US-9864913-B2
Application number	US-201514974428-A
Country	US
Kind code	B2
Filing date	Dec 18, 2015
Priority date	Jun 21, 2013
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

A device for safeguarding a monitoring area in which an automatically operating machine is arranged, having a camera system for monitoring the monitoring area, a configuration unit for defining at least one protection area within the monitoring area, and an analysis unit for triggering a safety-related function. The camera system supplies camera images of the protection area and the analysis unit analyzes whether a foreign object is present in the protection area or penetrates into the protection area. The analysis unit is configured to classify a foreign object, which is present in the protection area or penetrates into the protection area, by analysis of the camera images, to determine on the basis of one or more features characteristic of welding sparks whether the foreign object is a welding spark. The analysis unit triggers the safety-related function if the foreign object has not been recognized as a welding spark.

First claim

What is claimed is:

1. A device for safeguarding a monitoring area in which an automatically operating machine is arranged, the device comprising:
a camera system for monitoring the monitoring area;
a configuration unit for defining at least one protection area within the monitoring area; and
an analysis unit for triggering a safety-related function;
wherein the camera system is configured to generate camera images of the protection area,
wherein the analysis unit is configured to analyze the generated camera images to determine whether a foreign object is present in the protection area or about to penetrate into the protection area, wherein, if such a foreign object is determined to be present in the protection area or about to penetrate into the protection area, the analysis unit classifies said foreign object based on the generated camera
images, so as to determine on the basis of one or more features characteristic of welding sparks whether the foreign object is a welding spark, and
wherein the analysis unit is configured to trigger the safety-related function if the foreign object has not been recognized as a welding spark.

2. The device as claimed in claim 1 , further comprising an image correction unit which is configured to replace one or more image regions in the generated camera images if the foreign object is recognized as a welding spark.

3. The device as claimed in claim 2 , wherein the image correction unit is configured to replace said one or more image regions in the generated camera images with corresponding image data of temporally preceding camera images.

4. The device as claimed in claim 1 , wherein the analysis unit is configured to determine grayscale values of a plurality of pixels of the generated camera images, wherein the analysis unit is furthermore configured to compare said grayscale values to a grayscale threshold value, and wherein the analysis unit is configured to determine based on said comparison whether the foreign object is a welding spark.

5. The device as claimed in claim 1 , wherein the analysis unit is configured to determine based the generated camera images a speed of the foreign object, wherein the analysis unit is furthermore configured to compare the speed of the foreign object to a speed threshold value, and wherein the analysis unit is configured to determine based on said comparison whether the foreign object is a welding spark.

6. The device as claimed in claim 5 , wherein the analysis unit is configured to detect based on the generated camera images a distance of the foreign object to the camera system, and wherein the analysis unit is configured to determine the speed of the foreign object based on an illumination time of the camera system, the detected distance of the foreign object to the camera system, and a quantity of pixels that are occupied by the foreign object within the generated camera images.

7. The device as claimed in claim 1 , wherein the analysis unit is configured to determine a spatial distribution of grayscale values in an image region of at least one of the generated camera images if a foreign object is determined to be in said image region, and wherein the analysis unit is configured to determine based on the spatial distribution of grayscale values whether the foreign object is a welding spark.

8. The device as claimed in claim 7 , wherein the analysis unit is configured to determine based on the spatial distribution of grayscale values a gradient of the grayscale values in said image region in order to determine whether the foreign object is a welding spark.

9. The device as claimed in claim 8 , wherein the analysis unit is configured to identify the foreign object as a welding spark if the gradient of the grayscale values in said image region includes an exponential or nearly exponential decay of the grayscale values.

10. The device as claimed in claim 8 , wherein the analysis unit is furthermore configured to estimate a size of the foreign object based on the spatial distribution of grayscale values, and wherein the analysis unit is configured to determine based on the gradient of the grayscale values in said image region and based on the estimated size whether the foreign object is a welding spark.

11. The device as claimed in claim 8 , wherein the analysis unit is furthermore configured to estimate a shape of the foreign object based on the spatial distribution of grayscale values, and wherein the analysis unit is configured to determine based on the gradient of the grayscale values in said image region and based on the estimated shape whether the foreign object is a welding spark.

12. The device as claimed in claim 8 , wherein the analysis unit is furthermore configured to estimate a movement direction of the foreign object based on the spatial distribution of the grayscale values, and wherein the analysis unit is configured to determine based on the gradient of the grayscale values in said image region and based on the estimated movement direction whether the foreign object is a welding spark.

13. The device as claimed in claim 8 , wherein the analysis unit is furthermore configured to estimate a location of origin of the foreign object based on the spatial distribution of the grayscale values, and wherein the analysis unit is configured to determine based on the gradient of the grayscale values in said image region and based on the estimated location of origin whether the foreign object is a welding spark.

14. The device as claimed in claim 8 , wherein the analysis unit is furthermore configured to estimate at least two of a size, a shape, a movement direction, and a location of origin of the foreign object based on the spatial distribution of grayscale values, and wherein the analysis unit is configured to determine based on the gradient of the grayscale values in said image region and based on the at least two of the size, the shape, the movement direction, and the location of origin of the foreign object whether the foreign object is a welding spark.

15. The device as claimed in claim 7 , wherein the analysis unit is configured to generate a skeleton based on the spatial distribution of grayscale values and by means of a skeletonizing technique, wherein for generating said skeleton a chain of adjacent pixels having grayscale values greater than a grayscale threshold value is determined in at least one of the generated camera images, wherein the analysis unit is furthermore configured to determine a contour of the foreign object based on the skeleton, and wherein the analysis unit is configured to determine based on the determined contour whether the foreign object is a welding spark.

16. The device as claimed in claim 15 , wherein the analysis unit is configured to combine the grayscale values of adjacent pixels into groups for generating said skeleton.

17. The device as claimed in claim 1 , wherein the analysis unit is configured to compare temporally successive camera images to one another.

18. The device as claimed in claim 1 , wherein the camera system is a multichannel-redundant, multi-ocular camera system, which is configured to determine a distance value that is representative of a spatial location of the foreign object, wherein the distance value is determined by a runtime measurement method and/or by a stereoscopic comparison of two simultaneous camera images.

19. A method for safeguarding a monitoring area in which an automatically operating machine is arranged, having the following steps:
monitoring the monitoring area using a camera system,
defining at

Assignees

• Pilz Gmbh & Co Kg

Inventors

• Doettling Dietmar
• Hader Soeren

Classifications

• F16M11/105 Primary

  the horizontal axis being the roll axis, e.g. for creating a landscape-portrait rotation · CPC title

• G06V20/52

  Surveillance or monitoring of activities, e.g. for recognising suspicious objects (recognising microscopic objects G06V20/69) · CPC title

• H04N23/50

  Constructional details · CPC title

• G06T2207/30232

  Surveillance · CPC title

• G06T7/0008

  checking presence/absence · CPC title