Semiconductor laser-based area scanner

• US 6,787,756 B2
• Filed: 04/12/2001
• Issued: 09/07/2004
• Est. Priority Date: 04/12/2001
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Guenter, James K., Tatum, Jimmy A.
• Primary Examiner(s): Le, Que T.
• Application Number:
  US09/834,244
• Publication Number:
  US 20020148944A1
• Time in Patent Office: 1,244 Days
• US Class Current: 250/221
• CPC Class Codes: G01S 7/412 based on a comparison between measured values and known or stored values
• CPC Class Codes: G01S 7/417 involving the use of neural networks
• CPC Class Codes: G01S 7/4802 using analysis of echo signal for target characterisation; Target signature; Target cross-section
• CPC Class Codes: G01S 7/4815 using multiple transmitters

Abstract

Multiple laser optical sensing systems and methods for detecting target characteristics are disclosed. The present invention detects the presence of an object in a monitored area using an laser-based object detection system and may selectively cause a controlled response when an object is detected. At least two laser signals may be emitted into a monitored area using a vertical cavity surface emitting laser structure. At least one detector receives any laser signals not blocked by an object. The system determines the presence or absence of an object in the environment using a microprocessor and determines the objects characteristics by comparing received laser signals associated with it to object characteristics stored in a memory. The system may selectively causing a controlled response in accordance with the determination of object characteristics and/or correlating response criteria.

Claims

1. An area scanning system, comprising:

a laser source with at least two emission apertures, wherein said laser source is adapted by said emission apertures to emit at least two laser signals into an environment occupied by a target wherein the at least two laser signals can be reflected or absorbed by objects located in said environment and said environment;

at least one photodetector adapted to receive reflected laser signals from objects located in said environment and said environment;

a microprocessor operationally coupled to said at least one photodetector and having access to a database, wherein said microprocessor is programmed to determine target characteristics based on comparison of reflected laser signals received by said detector from said environment and any object located therein to target characteristics obtained from the database; and

a control module associated with and under the control of said microprocessor, said control module for triggering a response at the direction of said microprocessor, wherein the response is based onto the presence of at least one object located in said environment that can be identified by said microprocessor;

wherein said microprocessor analyzes laser signals received by said detector to determine the presence of objects identified by said system and located within said environment.

2. The system of claim 1 further comprising a memory for further providing said system with a target-free environment and/or known target characteristic data.

3. The system of claim 2 wherein object characteristics are determined by said system based on comparison of laser signals received by said detector after interference with objects newly introduced into said environment with said target characteristics stored in said database.

4. The system of claim 1, wherein said laser is a vertical cavity surface emitting laser.

5. The system of claim 1 further comprising a database storing reference characteristics associated with known objects, said reference chracteristics being accessible by said microprocessor from said database.

6. The system of claim 5 wherein said laser source emits at least two laser signals through at least two apertures associated with said laser source into an environment occupied by at least one object, said at least one photodetector detects said at least two laser signals after said signals pass through said environment containing at least one object, and said microprocessor determines characteristics associated with said at least one object based on comparison of said signals received by said photodetector with said object characteristics stored in said database.

7. The system of claim 5, wherein said laser is a vertical cavity surface emitting laser.

8. A method for detecting the presence of an object in a monitored area using an object detection system and selectively causing a response when an object is detected, comprising the steps of:

emitting at least two laser signals into a monitored area using a vertical cavity surface emitting laser structure;

receiving laser signals reflected and not blocked by said environment and at least one object target using at least one photodetector;

determining the presence or absence of at least one object in said environment using a microprocessor, wherein an object is present when at least one of said laser signals is blocked by at least one object;

using said microprocessor for determining characteristics of said at least one object by comparing laser signals received by said photodetector and associated with said at least one object with known object characteristics stored in a memory; and

using said microprocessor for selectively causing a controller response following said determination of object characteristics by said microprocessor.

9. The method of claim 8 further comprising training an object detection system to determine object characteristics through the steps of:

emitting at least one laser signal at a time into an environment using a vertical cavity surface emitting laser structure;

utilizing at least one photodetector for receiving laser signals reflected and not blocked by said test object and said environment, said laser signals representing object characteristics associated with said test object; and

storing said object characteristics in memory.

10. The method of claim 8, wherein said microprocessor determines the size or shape of said object by analyzing laser signals received by said photodetector alter different arrays of laser signals are emitted by said vertical cavity surface emitting laser structure into said environment and are subsequently compared with object characteristics stored in memory.

11. A method for scanning a monitored area and detecting the presence of predefined targets comprising the steps of:

providing a laser-based object detection system including a laser source for emitting at least two laser signals into an environment, at least one photodetector for receiving laser signals reflected off of targets in said test environment, and a microprocessor having access to data stored in memory and representing characteristics of known targets stored in the memory in the form of data associated with unique signature of reflected laser signals;

monitoring an environment, said environment having characteristics known by said laser-based object detection system to be associated with an object-free environment by emitting at least two laser signals into said environment wherein at least one of said at least two laser signals is blocked by at least one object, said at least one object interfering with said at least one laser signal;

detecting the presence of said at least one object in said environment by receiving said at least one laser signal being blocked by said at least one object through said at least one photodetector; and

determining with said microprocessor the identification of said at least one object in said environment by comparing said characteristics of known targets with said at least one signal received from said environment by said at least one photodetector.

12. The method of claim 11, wherein the size, shape and/or motion of said object is determined by analyzing laser signals received by said photodetector after different sequences of laser signals are emitted by said laser source.

13. The method of claim 11, wherein angular or spatial location of said at least one object are determined by comparing over time sequences of laser signals emitted by said laser source with corresponding sequences of laser signals received by said photodetector.

14. The method of claim 11, wherein the presence or absence of an object is determined by comparing sequences of laser signals emitted by said laser source with laser signals received by said photodetector.

15. The method of claim 11 wherein a control function associated with the detection and identification of said at least one object is executed.

16. The method of claim 15 wherein said control function is to turn at least one light within said environment.

17. The method of claim 15 wherein said control function is to activate an alarm if said at least one object is not identified.

18. The method of claim 15 wherein said control function is to activate a HVAC system associated with said environment.