Opto-electronic sensor array and a method to operate an opto-electronic sensor array

• US 20020109073A1
• Filed: 05/25/2001
• Published: 08/15/2002
• Est. Priority Date: 05/25/2000
• Status: Active Grant

• Current Assignee: Sick AG (Sick)
• Original Assignee: Sick AG (Sick)
• Inventors: Blohbaum, Frank
• Granted Patent: US 6,593,563 B2
• Time in Patent Office: Days
• US Class Current: 250/208.1
• CPC Class Codes: G01V 8/20 using multiple transmitters or receivers
• CPC Class Codes: G06V 10/145 Illumination specially adapted for pattern recognition, e.g. using gratings

Abstract

A method is described for the operation of an opto-electronic sensor array, in which a plurality of sequential operating light pulses are emitted into a monitored region; the operating light pulses reflected from an object arranged in the monitored region are received by a spatially resolving receiver unit with a plurality of light sensitive sensors; the light intensity of the respectively received reflected operating light pulses is detected and stored in each case during an activation interval synchronously with the emission of the operating light pulses for each sensor; and after each activation interval, in sequential transmission steps, the light intensities stored for the sensors are transmitted to a parallel processor having a plurality of parallel signal inputs for the parallel signal processing, with the transmission in each case taking place for a plurality of sensors simultaneously in each transmission step. Furthermore, a sensor array for the carrying out of the method is described.

Claims

1. A method for the operation of an opto-electronic sensor array, in which

a plurality of sequential operating light pulses are emitted into a monitored region;

the operating light pulses reflected from an object arranged in the monitored region are received by a spatially resolving receiver unit with a plurality of light sensitive sensors;

the light intensity of the respectively received reflected operating light pulses is detected and stored in each case during an activation interval synchronously with the emission of the operating light pulses for each sensor; and

after each activation interval, in sequential transmission steps, the light intensities stored for the sensors are transmitted to a parallel processor having a plurality of parallel signal inputs for the parallel signal processing, with the transmission in each case taking place for a plurality of sensors simultaneously in each transmission step;

2. A method in accordance with claim 1, characterized in that no storage of the light intensities incident on the sensors takes place outside the activation intervals.

3. A method in accordance with claim 1 or claim 2, characterized in that, during the transmission of the light intensity values, the light intensity values transmitted in a preceding transmission step are pre-processed by the parallel processor during the transmission of the light intensity values.

4. A method in accordance with one of the preceding claims, characterized in that the signal values pre-processed by the parallel processor are in each case fed to an evaluation unit for further signal processing for object recognition.

5. A method in accordance with one of the preceding claims, characterized in that the sensors are in each case only activated for the reception of the reflected operating light pulses during the activation intervals.

6. A method in accordance with one of the preceding claims, characterized in that the sensors are deactivated synchronously with the end of the operating light pulses emitted in each case.

7. A method in accordance with one of the preceding claims, characterized in that the length of the activation interval corresponds in each case to the length of the operating light pulses emitted synchronously thereto.

8. A method in accordance with one of the preceding claims, characterized in that the stored and detected values of the light intensities per sensor are subjected to an analog/digital conversion and the digital values are transmitted to the parallel processor.

9. A method in accordance with claim 8, characterized in that the analog/digital conversion takes place simultaneously for a plurality of sensors in each case.

10. A method in accordance with one of the preceding claims, characterized in that the sensors are arranged two-dimensionally in lines and/or columns respectively next to one another and the values of the light intensities stored in each case for a line or a column are transmitted to the parallel processor in each transmission step.

11. A method in accordance with claim 10, characterized in that the analog/digital conversion respectively takes place for all sensors of a line or a column simultaneously.

12. A method in accordance with one of the preceding claims, characterized in that, during the pre-processing by the parallel processor, relationships are evaluated in each case between the transmitted signal values of sensors arranged next to one another.

13. A method in accordance with claim 12, characterized in that an edge recognition signal is generated when the difference between the signal values of sensors arranged next to one another exceeds a pre-set threshold value.

14. A method in accordance with one of the preceding claims, characterized in that the storage of the light intensity takes place directly in the receiver unit for each sensor.

15. A method in accordance with one of the preceding claims, characterized in that the light intensity of the reflected operating light pulses that are received is stored for each sensor in digital and/or analog form.

16. An opto-electronic sensor array, in particular for the carrying out of the method in accordance with one of the preceding claims,

comprising a light transmitter (9) for the transmission of a plurality of sequential operating light pulses (10) into a monitored region and a spatially resolving receiver unit (1) having a plurality of light sensitive sensors (4) for the reception of operating light pulses (10′

) reflected from an object (29) arranged in the monitored region, having a synchronization unit for the synchronization of the operating light pulses (10) with an activation interval in which the sensors (4) can each be activated to detect the light intensity of the respectively received reflected operating light pulses (10′

), having a memory unit (13) in which the light intensity recorded during the activation interval can be stored for each sensor (4); and

comprising a parallel processor including a plurality of signal inputs (30) which is connected to corresponding outputs (31) of the receiver unit (1) for the parallel takeover of a plurality of values of the light intensities stored in the memory unit (13).

17. An opto-electronic sensor array in accordance with claim 16, characterized in that an evaluation unit is provided for the object recognition, to which the values of the light intensities respectively pre-processed in the parallel processor can be fed for the further signal processing.

18. An opto-electronic sensor array in accordance with claim 16 or claim 17, characterized in that the receiver unit (1) is formed as a sensor chip, in particular as a CMOS based sensor chip.

19. An opto-electronic sensor array in accordance with one of claims 16 to 18, characterized in that the sensors (4) are arranged in line form, column form, matrix form, circular form or trapezoid form.

20. An opto-electronic sensor array in accordance with claim 19, characterized in that each line (2, 2′

, 2″

) or each column (3) comprises the same number of sensors (4).

21. An opto-electronic sensor array in accordance with claim 19 or claim 20, characterized in that the number of sensors (4) per line (2, 2′

, 2″

) or per column (3) is the same as the number of signal inputs (30) of the parallel processor.

22. An opto-electronic sensor array in accordance with one of claims 16 to 21, characterized in that the parallel processor is formed integrally with the receiver unit (1).

23. An opto-electronic sensor array in accordance with one of claims 16 to 22, characterized in that a correlated double sampling stage is assigned to each sensor (4) which is in particular integrally formed with the receiver unit (1).

24. An opto-electronic sensor array in accordance with claim 23, characterized in that the correlated double sampling stages are formed for the compensation of different offset values of the individual sensors (4).