Optical area monitoring with spot matrix illumination

• US 9,696,424 B2
• Filed: 11/25/2014
• Issued: 07/04/2017
• Est. Priority Date: 05/19/2014
• Status: Active Grant

• Current Assignee: Rockwell Automation Technologies Incorporated (Allen-Bradley Co., Inc.)
• Original Assignee: Rockwell Automation Technologies Incorporated (Allen-Bradley Co., Inc.)
• Inventors: Galera, Richard, Jones, Derek W., Bowlby, Anne, Pradhan, Nilesh, Leard, Francis L.
• Primary Examiner(s): Dang, Duy M
• Application Number:
  US14/553,363
• Publication Number:
  US 20150331107A1
• Time in Patent Office: 952 Days
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01V 8/00 Prospecting or detecting by optical means
• CPC Class Codes: G06V 2201/07 Target detection
• CPC Class Codes: G06V 2201/121 using special illumination
• CPC Class Codes: H04N 13/207 using a single 2D image sensor
• CPC Class Codes: H04N 13/25 using two or more image sensors with different characteristics other than in their location or field of view, e.g. having different resolutions or colour pickup characteristics; using image signals from one sensor to control the characteristics of another sensor
• CPC Class Codes: H04N 13/257 Colour aspects
• CPC Class Codes: H04N 23/56 provided with illuminating means
• CPC Class Codes: H04N 23/741 by increasing the dynamic range of the image compared to the dynamic range of the electronic image sensors
• CPC Class Codes: H04N 25/585 with pixels having different sensitivities within the sensor, e.g. fast or slow pixels or pixels having different sizes

Abstract

An imaging sensor device is configured to illuminate a viewing field using an array of focused light spots spaced across the viewing field rather than uniformly illuminating the viewing field, thereby reducing the amount of illumination energy required to produce a given intensity of light reflected from the spots. In some embodiments, the imaging sensor device can project an array of focused light spots at two different intensities or brightness levels, such that high intensity and low intensity light spots are interlaced across the viewing field. This ensures that both relatively dark and relatively bright or reflective objects can be reliably detected within the viewing field. The intensities of the light spots can be modulated based on measured conditions of the viewing field, including but not limited to the measured ambient light or a determined dynamic range of reflectivity of objects within the viewing field.

Claims

1. An imaging sensor device, comprising:

a memory that stores executable components;

a processor, operatively coupled to the memory, that executes the executable components, the executable components comprising;

an illumination component configured to emit focused light beams to a viewing space monitored by the imaging sensor device to produce an array of light spots across the viewing space, the focused light beams comprising a first subset of the focused light beams having a first intensity and a second subset of the focused light beams having a second intensity;

a photo-receiver array configured to receive reflected light from the viewing space and produce pixel data for an image corresponding to the viewing space based on the reflected light;

an image analysis component configured to determine a location of an object in the viewing space based on analysis of the pixel data;

an ambient light measurement component configured to measure an amount of ambient light received at the photo-receiver array; and

an intensity modulation component configured to modify an intensity ratio between the first intensity and the second intensity based on the amount of ambient light.

2. The imaging sensor device of claim 1, wherein the illumination component comprises at least one pattern generator that focuses light from a light source into the focused light beams.

3. The imaging sensor device of claim 2, wherein the at least one pattern generator is configured to focus the light from the light source to produce the first subset of the focused light beams at the first intensity and the second subset of the focused light beams at the second intensity.

4. The imaging sensor device of claim 3, wherein the at least one pattern generator comprises a first set of emitting elements configured to produce the first subset of the focused light beams and a second set of emitting elements configured to produce the second subset of the focused light beams.

5. The imaging sensor device of claim 1, wherein the array of light spots comprise a first set of light spots corresponding to the first subset of the focused light beams interlaced with a second subset of the light spots corresponding to the second subset of the focused light beams.

6. The imaging sensor device of claim 1, wherein the illumination component comprises a first pattern generator that receives light from a first light source element to produce the first subset of the focused light beams and a second pattern generator configured to receive light from a second light source element to produce the second subset of the focused light beams.

7. The imaging sensor device of claim 6, wherein the intensity modulation component is configured to adjust an intensity of at least one of the first light source element or the second light source element based on the amount of ambient light received at the photo-receiver array.

8. The imaging sensor device of claim 1, wherein the intensity modulation component is further configured to modify the intensity ratio based on a measured difference in reflectivity between a first object detected in the viewing space and a second object detected in the viewing space.

9. The imaging sensor device of claim 1, further comprising a control output component configured to generate at least one of a control output or a message output based on an output generated by the image analysis component.

10. The imaging sensor device of claim 1, wherein the ambient light measurement component is configured to measure, as the amount of ambient light, an amount of ambient light received at photo-receivers of the photo-receiver array corresponding to pixels that are between light spots of the array of light spots.

11. A method for optically monitoring a viewing field, comprising:

emitting, by an imaging sensor device comprising at least one processor, focused light beams to a viewing field to yield light spots across the viewing field, the emitting comprising emitting a first subset of the focused light beams at a first intensity and emitting a second subset of the focused light beams at a second intensity;

measuring, by the imaging sensor device, an amount of ambient light received at a photo-receiver array of the imaging sensor device;

modifying, by the imaging sensor device, a ratio of the first intensity to the second intensity based on the amount of ambient light;

generating, by the imaging sensor device, pixel data for an image of the viewing field based on reflected light received from the viewing field; and

determining, by the imaging sensor device, a location of an object in the viewing field based on object location analysis performed on the pixel data.

12. The method of claim 11, wherein the emitting comprises directing light from a light source of the imaging sensor device to at least one pattern generator that concentrates the light into the focused light beams.

13. The method of claim 12, wherein the emitting comprises focusing, by the at least one pattern generator, the light from the light source to yield the first subset of the focused light beams at the first intensity and the second subset of the light beams at the second intensity.

14. The method of claim 13, wherein the emitting comprises directing the light beams to yield a first set of light spots corresponding to the first subset of the focused light beams interlaced with a second subset of the light spots corresponding to the second subset of the focused light beams.

15. The method of claim 14, further comprising:

changing an intensity of the light from the light source based on the amount of ambient light.

16. The method of claim 11, wherein the emitting comprises:

directing light from a first light source element to a first pattern generator at the first intensity to yield the first subset of the focused light beams; and

directing light from a second light source element to a second pattern generator at the second intensity to yield the second subset of the focused light beams.

17. The method of claim 11, further comprising:

measuring a difference in reflectivity between a first object detected in the viewing field and a second object detected in the viewing field; and

modifying the ratio of the first intensity to the second intensity further based on the difference.

18. A non-transitory computer-readable medium having stored thereon instructions that, in response to execution, cause an imaging sensor device comprising a processor to perform operations, the operations comprising:

emitting focused light beams to a viewing space to produce an array of light spots across the viewing space, the focused light beams comprising a first subset of the focused light beams having a first intensity and a second subset of the focused light beams having a second intensity;

measuring an amount of ambient light of the viewing space;

adjusting a ratio between the first intensity and the second intensity based on the amount of ambient light;

generating pixel data for an image of the viewing space based on reflected light received from the viewing space;

performing object identification analysis on the pixel data; and

identifying an object in the viewing field based on a result of the object identification analysis.

19. The non-transitory computer-readable medium of claim 18, wherein the

measuring the amount of ambient light comprises measuring an amount of the ambient light received at photo-receivers of a photo-receiver array of the imaging sensor device corresponding to pixels located between light spots of the array of light spots.

20. The non-transitory computer-readable medium of claim 18, the operations further comprising:

measuring a difference in reflectivity between a first object detected in the viewing field and a second object detected in the viewing field; and

adjusting the ratio between the first intensity and the second intensity further based on the difference in reflectivity.