Laser grid for measuring distance

• US 20050007348A1
• Filed: 05/10/2004
• Published: 01/13/2005
• Est. Priority Date: 11/08/2001
• Status: Active Grant

• Current Assignee: Rockwell Automation, Inc.
• Original Assignee: Siemens AG
• Inventors: Mengel, Peter, Waschke, Holger
• Granted Patent: US 7,034,950 B2
• Time in Patent Office: Days
• US Class Current: 345/168
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01S 17/87 Combinations of systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 7/481 Constructional features, e.g. arrangements of optical elements

Abstract

The laser grid (1) permits a single-sided installation in order to record a person or object in the monitoring area. The grid operates using punctiform sensor units (3), each including at least one laser diode and two photosensitive pixels. The sensor units are arranged in a line in a housing (2).

Claims

1. A distance measuring light grid comprising:

a plurality of transmitting and receiving elements arranged in punctiform sensor units that respectively have at least one laser diode and two photosensitive pixels; and

a housing in which the sensor units are arranged in a line.

2. The distance measuring light grid as claimed in claim 1, wherein the sensor units are 3D CMOS sensors.

3. The distance measuring light grid as claimed in claim 1, wherein the housing comprises a clock generator, an analog-to-digital converter and a processing logic circuit, wherein the clock generator is configured to trigger the sensor units, wherein the sensor units are configured to execute individual measurements and provide analog measured values, wherein the analog-to-digital converter is configured to output the measured values to the processing logic circuit, and wherein the processing logic circuit is configured to process the measured values.

4. The distance measuring light grid as claimed in claim 3, wherein the processing logic circuit is configured to calculate at least one distance from the measured values.

5. The distance measuring light grid as claimed in claim 3, wherein the processing logic circuit comprises a background filter that subtracts the measured values from a set of static background values.

6. The distance measuring light grid as claimed in claim 3, wherein the processing logic circuit comprises a threshold filter for identifying an object in a plurality of differing approach zones.

7. The distance measuring light grid as claimed in claim 3, wherein the processing logic circuit is configured to logically combine the measured values of a plurality of the sensor units and to detect a size of an object from the combined values.

8. The distance measuring light grid as claimed in claim 3, wherein the processing logic circuit comprises a muting function configured to mask out at least one of the measured values.

9. The distance measuring light grid as claimed in claim 3, wherein the housing further comprises an interface configured to interconnect the processing logic circuit to an external measuring and monitoring system.

10. A light grid comprising:

a plurality of sensor units mounted to form a sensor row, each of the sensor units comprising at least one laser diode and two photosensitive pixels, wherein each of the sensor units is configured to register an object in a laser path of the laser diode; and

a housing mounting the sensor row.

11. The light grid as claimed in claim 10, wherein the housing comprises at least one signal processor processing output signals from the plurality of sensor units into an object distance measurement.