Object sensor system comprising controlled light source

• US 6,298,175 B1
• Filed: 10/17/1997
• Issued: 10/02/2001
• Est. Priority Date: 10/17/1997
• Status: Expired due to Fees

• Current Assignee: Welch Allyn Incorporated
• Original Assignee: Welch Allyn Incorporated
• Inventors: Husssey, Robert M., Longacre, Andrew Jr.
• Primary Examiner(s): Couso, Jose L.
• Assistant Examiner(s): Dang, Duy M.
• Application Number:
  US08/953,191
• Time in Patent Office: 1,446 Days
• Field of Search: 382/312, 382/313, 382/314, 382/315, 382/316, 382/317, 382/318, 382/319, 382/321, 382/322, 382/323, 382/324, 315/82, 315/159, 307/10.8, 307/121, 235/462.48, 235/472.02, 235/462.47, 235/462.34, 235/462.45, 235/455, 361/683, 361/729, 361/731, 361/814, 364/708.1, 455/90, 455/348, 318/457, 340/429, 358/464, 358/447, 358/471
• US Class Current: 382/312
• CPC Class Codes: G06K 2207/1012 Special detection of object
• CPC Class Codes: G06K 7/10584 Source control
• CPC Class Codes: G06K 7/10732 Light sources

Abstract

This relates to a system for sensing the presence of an object in the field of view of an imaging assembly of a stationary position optical reader. The system includes a light source disposed in a field of view of the imaging assembly, which is configured to emit light in the direction of the imaging assembly according to a predetermined light pattern. A determination as to whether an object is present in a presentation area of the reader system is made by detecting for the presence of the light pattern in image information generated by the imaging assembly.

Claims

1. A system for sensing the presence of an object, said system comprising:

an optical reader including an imaging assembly for generating image information and a controller in communication with a memory space for controlling said imaging assembly;

a light source controlled by said controller positioned to emit light in a field of view of said imaging assembly, wherein said controller controls an illumination level of said light source by controlling electrical current supplied to a light emitting element of said light source,

wherein said controller is configured to capture frames of image data representing scenes defined by said field of view, wherein said controller controls said light source to define a predetermined light sequence characterized by said light source emitting light at different illumination levels during successive frame capture periods of said controller, wherein said controller is adapted to analyze image information developed during said successive frame capture periods to detect whether said predetermined light sequence is represented in said image information, and wherein an operating state of said reader depends on whether said controller detects said predetermined light sequence in said image information.

2. The system of claim 1, wherein said controller analyzes said image data of said captured frames of image data in detecting whether said predetermined light sequence is represented in said image information.

3. The system of claim 1, wherein said controller analyzes analog signal information output by said imaging assembly in detecting whether said predetermined light sequence is represented in said image information.

4. The system of claim 1, wherein said predetermined light sequence emitted by said light source is characterized by said light source being activated and subsequently deactivated in successive frame capture periods of said controller.

5. The system of claim 1, wherein said light source is positioned to direct light toward said imaging assembly so that an object located in a certain position within said field of view intermediate said illumination assembly and said light source prevents light emitted from said light source from being received by said imaging assembly.

6. A method for operating a stationary position type optical reader having an imaging assembly and a controller in communication with a memory, said imaging, assembly including an illumination source, said controller being configured to capture frames of image data into said memory, said method comprising the steps of:

providing a light source controlled by said controller to emit light in a field of view of said imaging assembly, wherein said controller controls an illumination level of said light source by controlling electrical current supplied to a light emitting element of said light source;

coordinating operation of said light source and said controller so that said light source emits light according to a predetermined light sequence characterized by said light source emitting light at a first illumination level when a first frame of image data is captured by said controller and at a second illumination level when a second frame of image data is captured by said controller;

in an active operating state, analyzing image information developed when said first and second frames of image data are captured to detect whether said predetermined light sequence is represented in image information generated by said imaging assembly; and

switching operation of said reader to an inactive operating state when said predetermined light sequence is represented in said image information.

7. The method of claim 6, further comprising the step of deactivating an illumination source of said imaging assembly when said reader is switched to said inactive operating state.

8. The method of claim 6, wherein said detecting step includes the step of analyzing image data captured by said controller.

9. The method of claim 6, wherein said detecting step includes the step of analyzing analog signal information generated by said imaging assembly.

10. The method of claim 6, further comprising the step of altering operation of said reader to a second inactive state when an exit condition is satisfied and said predetermined light sequence is not represented in said image information.

11. The method of claim 6, wherein said coordinating step includes the step of activating and subsequently deactivating said light source during successive frame capture periods of said controller.

12. The method of claim 6, wherein said positioning step includes the step of locating said light source to direct light toward said imaging assembly so that an object located in a certain position within said field of view intermediate said illumination assembly and said light source prevents light emitted from said light source from being received by said imaging assembly.

13. A method for operating a stationary position type optical reader having an imaging assembly and a controller in communication with a memory, said controller being configured to capture frames of image data into said memory, said method comprising the steps of:

emitting light in a field of view of said imaging assembly according to a predetermined sequence characterized by said light source emitting light at a first illumination level when a first frame of image data is captured by said controller and at a second illumination level when a second frame of image data is captured by said controller, wherein said first and second illumination levels are controlled by controlling an amount of electrical current supplied to a light emitting element of a light source;

in an active operating state, analyzing image information developed over the course of capturing said first and second frames of image data to detecting whether said predetermined light sequence is represented in image information generated by said imaging assembly; and

switching operation of said reader to an inactive operating state when said predetermined light sequence is represented in said image information.

14. The method of claim 13, wherein said detecting step includes the step of analyzing image data captured by said controller.

15. The method of claim 13, wherein said detecting step includes the step of analyzing analog signal information generated by said imaging assembly.

16. The method of claim 13, further comprising the step of altering operation of said reader to a second inactive state when an exit condition is satisfied and said predetermined light sequence is not represented in said image information.

17. The method of claim 13, wherein said coordinating step includes the step of activating and subsequently deactivating said light source during successive frame capture periods of said controller.