3D SENSOR

• US 20110001799A1
• Filed: 07/01/2010
• Published: 01/06/2011
• Est. Priority Date: 07/06/2009
• Status: Abandoned Application

• Current Assignee: Sick AG (Sick)
• Original Assignee: Sick AG (Sick)
• Inventors: ROTHENBERGER, Bernd, BRAUNE, Ingolf, MACNAMARA, Shane
• Application Number:
  US12/829,058
• Publication Number:
  US 20110001799A1
• Time in Patent Office: Days
• US Class Current: 348/47
• CPC Class Codes: G06T 2207/10012 Stereo images
• CPC Class Codes: G06T 7/187 involving region growing; involving region merging; involving connected component labelling
• CPC Class Codes: G06T 7/50 Depth or shape recovery
• CPC Class Codes: G06V 20/52 Surveillance or monitoring of activities, e.g. for recognising suspicious objects recognising microscopic objects G06V20/69

Abstract

A 3D sensor (10) having at least one image sensor (14) for the generation of image data of a monitored region (12) as well as a 3D evaluation unit (28) are provided, the evaluation unit (28) is adapted for the calculation of a depth map having distance pixels from the image data and for the determination of reliability values for the distance pixels. In this respect a gap evaluation unit (28) is provided which is adapted to recognize regions of the depth map with distance pixels whose reliability value does not satisfy a reliability criteria as gaps (42) in the depth map and to evaluate whether the depth map has gaps (42) larger than an uncritical maximum size.

Claims

1. A 3D sensor (10) having at least one image sensor (14) for the generation of image data of a monitored region (12) and a 3D evaluation unit (28) which is adapted for the calculation of a depth map having distance pixels from the image data and for the determination of reliability values for the distance pixels, characterized by a gap evaluation unit (28) which is adapted to recognize regions of the depth map with distance pixels whose reliability value does not satisfy a reliability criteria as gaps (42) in the depth map and to evaluate whether the depth map has gaps (42) larger than an uncritical maximum size.

2. A 3D sensor (10) in accordance with claim 1, wherein the gap evaluation unit (28) is adapted for an evaluation of the size of gaps (42) by means of a largest possible geometric shape (42b) inscribed into the gap, in particular by means of a diameter of an inner circle or of a diagonal of an inner rectangle.

3. A 3D sensor (10) in accordance with claim 1 having an object evaluation unit (28) which is adapted to recognize connected regions of distance pixels as objects (40) and to evaluate the size of an object (40) by means of a smallest possible geometric shape (42a) surrounding the object (40), in particular by means of a diameter of a circumference or a diagonal of a surrounding rectangle.

4. A 3D sensor (10) in accordance with claim 3, wherein the object evaluation unit (28) is adapted to generate a binary map in a first step, said binary map records in every pixel whether the reliability value of the associated distance pixel satisfies the reliability criteria and thus whether it is occupied with a valid distance value or not, then in a further step defines partial objects (46a-e) in a single linear scanning run, in that an occupied distance pixel without an occupied neighbour starts a new partial object (46a-e) and attaches occupied distance pixels with at least one occupied neighbour to the partial object (46a-e) of an occupied neighbour and wherein in a third step, partial objects (46a-e) which have at most a preset distance to one another are combined to the object.

5. A 3D sensor (10) in accordance with claim 1, wherein the gap evaluation unit and/or the object evaluation unit is adapted to overestimate the size of a gap (42) or an object (40), in particular by projection on to the remote border of the monitored region (12) or of a work region (32).

6. A 3D sensor (10) in accordance with claim 1, wherein the gap evaluation unit (28) and/or the object evaluation unit (28) is adapted to calculate gaps (42) or objects (40) of the depth map in a single linear scanning run in real time.

7. A 3D sensor (10) in accordance with claim 1, wherein the gap evaluation unit (28) is adapted to determine the size of the gaps (42) by successively generating an evaluation map s in accordance with the calculation rule,

8. A 3D sensor (10) in accordance with claim 1 having at least two image sensors (14a-b) for the reception of image data from the monitored region (12) from different perspectives, wherein the 3D evaluation unit (28) is adapted for the generation of the depth map and the reliability values using a stereoscopic method.

9. A 3D sensor (10) in accordance with claim 1, wherein a warning unit or cut off unit (34) is provided, by means of which by detection of gaps (42) or prohibited objects (40) larger than the uncritical maximum size a warning signal or a safety cut off command can be issued to a dangerous machine (30).

10. A 3D sensor (10) in accordance with claim 1, wherein a work region (32) is preset as a partial region of the monitored region (12) and the 3D evaluation unit (28), the gap evaluation unit (28) and/or the object evaluation unit (28) only evaluates the depth map within the work region (32).

11. A 3D monitoring process, in particular a stereoscopic monitoring process in which image data from a monitored region (12) generate depth maps having distance pixels, as well as a respective reliability value for each distance pixel, characterized in that regions of the depth map having distance pixels whose reliability values do not satisfy a reliability criterion are detected as gaps (42) in the depth map and an evaluation is made whether the depth map has gaps (42) which are larger than an uncritical maximum size.

12. A 3D monitoring process in accordance with claim 11, wherein the size of gaps (42) is evaluated by means of a largest possible inscribed geometric shape (42b), in particular by means of a diameter of an inner circle or a diagonal of an inner rectangle and/or wherein connected regions of distance pixels are recognized as objects (40) and the size of an object (40) is evaluated by means of a smallest possible shape (40a) surrounding the object, in particular by means of a diameter of a circumference or a diagonal of a surrounding rectangle.

13. A 3D monitoring process in accordance with claim 11, wherein the size of a gap (42) or an object (40) is overestimated, in particular by projection on to the remote border of the monitored region (12) or a work region (32).

14. A 3D monitoring process in accordance with claim 11, wherein the gaps (42) or objects (40) of the depth map are calculated in real time in a single linear scanning run.

15. A 3D monitoring process in accordance with claim 11, wherein on detection of gaps (42) or prohibited objects (40) larger than the uncritical maximum size a warning signal or a safety cut off command is issued to a dangerous machine (30).