Digital image capture and processing system employing a micro-computing platform with an event-driven multi-tier modular software architecture and supporting an image-processing based illumination metering program for automatically adjusting illumination during object illumination and imaging operations

• US 7,637,433 B1
• Filed: 05/11/2007
• Issued: 12/29/2009
• Est. Priority Date: 11/13/2003
• Status: Active Grant

• Current Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Original Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Inventors: Zhu, Xiaoxun, Au, Ka Man, Liu, Yong, Liu, Liang, Kotlarsky, Anatoly, Tao, Xi, Zhang, Wenhua, Hou, Rui, Yu, Hongpeng
• Primary Examiner(s): Kim; Ahshik
• Application Number:
  US11/818,155
• Time in Patent Office: 963 Days
• Field of Search: 235/462.42, 235/462.01, 235/462.09, 235/462.15, 235/462.43
• US Class Current: 235/462.42
• CPC Class Codes: G06F 9/44526 Plug-ins; Add-ons
• CPC Class Codes: G06K 2207/1012 Special detection of object
• CPC Class Codes: G06K 7/10712 Fixed beam scanning
• CPC Class Codes: G06K 7/10732 Light sources
• CPC Class Codes: G06K 7/10831 Arrangement of optical elements, e.g. lenses, mirrors, prisms optical elements per se G02B
• CPC Class Codes: G06K 7/10851 Circuits for pulse shaping, amplifying, eliminating noise signals, checking the function of the sensing device basic electronic circuitry H03
• CPC Class Codes: G06K 7/10881 constructional details of hand-held scanners
• CPC Class Codes: G06K 7/14 using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence

Abstract

A digital image capture and processing system comprising an illumination measurement subsystem for measuring the level of illumination at a particular region of the field of view (FOV) of the system during object illumination and imaging operations, and producing and storing an illumination measure for achieving a desired spatial intensity in a digital image to be formed and detected by the image formation and detection subsystem. An illumination control subsystem uses the illumination measure to control a LED-based illumination array during object illumination and imaging operations. A programmed image processor supports an image-processing based illumination metering program, as well as processes digital images formed and detected by the image formation and detection subsystem so as to read or acquire information graphically represented in the digital images. A computing platform supports the implementation of one or more of the subsystems above, and includes memory for storing at least one code symbol reading application.

Claims

1. A digital image capture and processing system comprising:

a housing having a light transmission window;

a digital image formation and detection subsystem having (i) image formation optics for projecting a field of view (FOV) from an area-type image detection array, upon an object to be imaged during object illumination and imaging operations, and (ii) said area-type image detection array detecting digital images of the object during said object illumination and imaging operations;

a trigger event generation mechanism, disposed in said housing, for automatically detecting the presence of an object within said FOV;

an illumination subsystem, disposed in said housing, and having an LED-based illumination array for producing a field of illumination with said FOV during object illumination and imaging operations;

an illumination measurement subsystem, disposed in said housing, for measuring the level of illumination at a particular region of said FOV during object illumination and imaging operations, and producing and storing an illumination measure for achieving a desired spatial intensity in a digital image to be formed and detected by said digital image formation and detection subsystem;

an illumination control subsystem, disposed in said housing, using said illumination measure to control said LED-based illumination array during object illumination and imaging operations;

a programmed image processor, disposed in said housing, for supporting an image-processing based illumination metering program to analyze and measure the spatial intensity distribution of said digital images formed and detected by said digital image formation and detection subsystem, as well as for processing said digital images so as to read or acquire information graphically represented in said digital images;

a system control subsystem, disposed in said housing, for controlling and/or coordinating the operations of said subsystems and components identified above; and

a computing platform for supporting the implementation of one or more of said subsystems above, and including (i) memory for storing at least one code symbol reading application, and (ii) a microprocessor for running said at least one code symbol reading application;

wherein said memory comprises a memory architecture that supports a multi-tier modular software architecture characterized by an Operating System (OS) Layer, and an Application Layer in which said at least one code symbol reading application is automatically loaded and responds to the generation of a triggering event within said digital image capture and processing system.

2. The digital image capture and processing system of claim 1, wherein said multi-tier modular software architecture is further characterized by a System CORE (SCORE) layer.

3. The digital image capture and processing system of claim 1, wherein said illumination measurement subsystem further comprises a photodetector, operating independently from said image detecting array, for measuring said level of illumination at a particular region of said FOV during object illumination and imaging operations.

4. The digital image capture and processing system of claim 1, wherein said illumination measure is an illumination duration necessary for achieving the desired spatial intensity in the digital image to be formed and detected by said digital image formation and detection subsystem;

and wherein said illumination control subsystem uses said illumination duration to control the time duration that said LED-based illumination array is driven during object illumination and imaging operations.

5. The digital image capture and processing system of claim 1, wherein said computing platform further comprises Flash ROM for storing said at least one code symbol reading application, and RAM for storing said digital images captured and buffered by said image capturing and buffering subsystem.

6. The digital image capture and processing system of claim 1, wherein said FOV is projected through said light transmission window and upon the object to be imaged in said FOV.

7. The digital image capture and processing system of claim 1, wherein said housing contains all of said subsystems.

8. The digital image capture and processing system of claim 1, wherein said computing platform implements said programmed image processor and said system control subsystem.

9. The digital image capture and processing system of claim 2, wherein said OS Layer includes one or more software modules selected from the group consisting of an OS kernel module, an OS file system module, and device driver modules;

wherein said SCORE Layer includes one or more of software modules selected from the group consisting of a tasks manager module, an events dispatcher module, an input/output manager module, a user commands manager module, a timer subsystem module, an input/output subsystem module and a memory control subsystem module; and

wherein said Application Layer includes one or more software modules selected from the group consisting of a code symbol decoding module, a function programming module, an application events manager module, a user commands table module, and a command handler module.

10. The digital image capture and processing system of claim 9, wherein, prior to capturing one or more digital images of the object, said microprocessor rapidly initializes said computing platform by performing the following operations:

(1) accessing one or more software modules from said OS layer and executing code contained therein;

(2) accessing one or more software modules from said SCORE layer and executing code contained therein; and

(3) accessing one or more software modules from said Application Layer and executing code contained therein.

11. The digital image capture and processing system of claim 1, wherein said field of illumination comprises narrow-band illumination produced from an array of light emitting diodes (LEDs).

12. The digital image capture and processing system of claim 1, wherein said computing platform implements said input/output subsystem and said system control subsystem, and wherein said Application Layer includes said one or more libraries and said one or more libraries include one or more software modules selected from the group consisting of a code symbol decoding module, a function programming module, an application events manager module, a user commands table module, and a command handler module.

13. The digital image capture and processing system of claim 1, which further comprises an automatic object detection subsystem for automatically detecting the presence of the object in said FOV, and in response thereto, generating a trigger signal indicative of said triggering event.

14. The digital image capture and processing system of claim 1, which further comprises a trigger manually actuatable by an operator of said digital image capturing and processing system so as to generate a trigger signal indicative of said triggering event.

15. The digital image capture and processing system of claim 3, wherein said trigger event generation mechanism comprises an automatic object presence detector, wherein when the object is moved into said FOV, said trigger event generation mechanism automatically generates said trigger event within said system;

and

wherein, in response to the generation of said trigger event, the following sequence of operations are carried out under the control and/or coordination of said digital image capture and processing system control subsystem;

(1) said illumination subsystem produces and projects said field of illumination within said FOV and onto said detected object;

(2) said photodetector employed in said illumination measurement subsystem automatically measures the level of illumination at the particular region of said FOV, and produces and stores said illumination measure for achieving the desired spatial intensity in the digital image to be formed and detected by said digital information and detection subsystem;

(3) said illumination control subsystem uses said produced illumination measure to control said LED-based illumination array during object illumination and imaging operations;

(4) said digital image formation and detection subsystem forms and detects one or more digital images of the illuminated object within said FOV;

(5) said programmed image processor uses said image-processing based illumination metering program to analyze and measure, in real-time, the spatial intensity distribution of the detected digital image, and determines whether or not a corrected illumination measure is required when forming and detecting a next or subsequent digital image during the current or subsequent illumination and imaging operation;

(6) in the event that said programmed image processor determines that a corrected illumination duration is required, then said programmed image processor over-writes the previously determined and stored illumination measure, with the corrected illumination measure; and

(7) said illumination control subsystem uses the corrected illumination measure to control said LED-based illumination array during the subsequent object illumination and imaging operations, so that said digital image formation and detection subsystem forms and detects one or more digital images of the illuminated object.

16. The digital image capture and processing system of claim 15, wherein said system control subsystem coordinates system operations so that operations (1) through (7) are repeated one or more additional times in a recursive manner during each illumination and imaging operation, so as to produce a digital image having a spatial intensity level with high image contrast.

17. The digital image capture and processing system of claim 15, wherein said particular region is a central region of said FOV.

18. The digital image capture and processing system of claim 3, wherein said trigger event generation mechanism comprises a trigger switch that is manually actuated by an operator, and wherein in response to the object being moved into said FOV, the operator generates said trigger event by manually actuating said trigger switch;

wherein, in response to the generation of said trigger event, the following sequence of operations are carried out under the control and/or coordination of said system control subsystem;

(1) said illumination subsystem produces and projects said field of illumination within said FOV and onto said detected object;

(2) said photodetector employed in said illumination measurement subsystem automatically measures the level of illumination at the particular region of said FOV, and produces and stores the illumination measure for achieving the desired spatial intensity in the digital image to be formed and detected by said information and detection subsystem;

(3) said illumination control subsystem uses said determined illumination measure to control said LED-based illumination array during object illumination and imaging operations;

(4) said digital image formation and detection subsystem forms and detects a digital image of the illuminated object within said FOV;

(5) said programmed image processor uses said image-processing based illumination metering program to analyze and measure, in real-time, the spatial intensity distribution of the detected digital image, and determines whether or not a corrected illumination measure is required when forming and detecting a next or subsequent digital image during the current or subsequent illumination and imaging operation;

(6) in the event that said programmed image processor determines that a corrected illumination measure is required, then said programmed image processor over-writes the previously determined and stored illumination measure, with the corrected illumination measure; and

(7) said illumination control subsystem uses the corrected illumination measure to control said LED-based illumination array during the subsequent object illumination and imaging operations, so that said digital image formation and detection subsystem forms and detects one or more digital images of the illuminated object.

19. The digital image capture and processing system of claim 18, wherein said system control subsystem coordinates system operations so that operations (1) through (7) are repeated one or more additional times in a recursive manner during each illumination and imaging operation, so as to produce digital images having an optimized spatial intensity level with high image contrast.

20. The digital image capture and processing system of claim 4, wherein said illumination duration is a time count stored in memory within said digital image capture and processing system.

21. The digital image capture and processing system of claim 1, wherein said housing is hand-supportable.

22. The digital image capture and processing system of claim 1, wherein said housing is supportable upon the countertop surface of a point of sale (POS) station.

23. The digital image capture and processing system of claim 1, wherein said programmed image processor processes said one or more digital images, so as to read one or more code symbols graphically represented therein, and producing output data in the form of symbol character data representative of said read one or more code symbols.

24. The digital image capture and processing system of claim 23, wherein each said code symbol is a bar code symbol selected from the group consisting of a 1D bar code symbol, a 2D bar code symbol, and a data matrix type code symbol structure.