Portable digital image capturing and processing system employing an area-type image sensing array exposed to illumination produced from an LED-based illumination array and measured using a photodector operated independently from said area-type image sensing array

• US 20070138292A1
• Filed: 11/27/2006
• Published: 06/21/2007
• 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, Liu, Yong, Liu, Liang, Kotlarsky, Anatoly, Tao, Xi, Zhang, Wenhua, Hou, Rui, Yu, Hongpeng, Au, Ka
• Granted Patent: US 7,510,122 B2
• Time in Patent Office: Days
• US Class Current: 235/462.450
• CPC Class Codes: G06K 7/10732 Light sources
• 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

Abstract

A portable digital image capturing and processing system comprising an image formation and detection subsystem, an LED-based illumination subsystem, an automatic light exposure measurement subsystem, and an automatic illumination control subsystem. The image formation and detection subsystem has an area-type image sensing array for detecting digital images of objects formed thereon by image formation optics providing a field of view (FOV) for the system. The automatic light exposure measurement subsystem employs a photodetector operated independently from the area-type image sensing array, for automatically measuring the light exposure incident upon a selected portion of the FOV, and producing an electrical signal representative of the light exposure measurement. The automatic illumination control subsystem responds to the electrical signal and controls the duration of LED-based illumination produced from the LED-based illumination subsystem during the image capture mode.

Claims

1. A portable digital image capture and processing system comprising:

a hand-supportable housing;

an image formation and detection subsystem, disposed in said hand-supportable housing, and having image formation optics for producing a field of view (FOV) upon an object to be imaged, and an area-type image sensing array for detecting imaged light reflected off the object during illumination operations in an image capture mode in which rows of sensor elements in said area-type image sensing array are enabled so as to detect a 2D digital image of the object formed on said area-type image sensing array;

an LED-based illumination subsystem, disposed in said hand-supportable housing, and having an LED-based illumination array for producing a field of LED-based illumination within the FOV of said image formation and detection subsystem during the image capture mode;

an automatic light exposure measurement subsystem disposed in said hand-supportable housing, employing a photodetector operated independently from said area-type image sensing array, for automatically measuring the light exposure incident upon a selected portion of said FOV, and producing an electrical signal representative of said light exposure measurement;

an automatic illumination control subsystem disposed in said hand-supportable housing, for automatically controlling the operation of said LED-based illumination subsystem,

wherein said automatic illumination control subsystem responds to said electrical signal and controls the duration of LED-based illumination produced from said LED-based illumination subsystem during said image capture mode;

an image capturing and buffering subsystem disposed in said hand-supportable housing, for capturing and buffering 2D digital images detected by said image formation and detection subsystem;

an image-processing subsystem disposed in said hand-supportable housing, for processing 2D digital images captured and buffered by said image capturing and buffering subsystem and producing processed image data; and

an input/output subsystem disposed in said hand-supportable housing, for outputting processed image data to an external host system or other information receiving or responding device; and

a system control subsystem disposed in said hand-supportable housing, for controlling and/or coordinating the operation of the subsystem components described above.

2. The hand-supportable digital image capture and processing system of claim 1, which further comprises:

an automatic object presence detection subsystem for producing an object detection field within the FOV of said image formation and detection subsystem, and automatically detecting the presence of an object in said FOV and generating a control activation signal in response to said object detection.

3. The hand-supportable digital image capture and processing system of claim 1, wherein said selected portion of said FOV is a central portion of said FOV.

4. The hand-supportable digital image capture and processing system of claim 1, wherein said LED-based illumination comprises narrow-band illumination.

5. The hand-supportable digital image capture and processing system of claim 1, wherein said automatic light exposure measurement subsystem comprises a light collecting optical component arranged within said hand-supportable housing,

wherein incident LED-based illumination is collected from the selected portion of said FOV using said light collecting optical component, and then focused upon said photodiode for detection of the intensity of collected LED-based illumination and generation of an electrical signal corresponding to the detected intensity and for subsequent processing by said automatic light exposure measurement subsystem, so as to control the illumination produced by said LED-based illumination subsystem and light exposure received by said area-type image sensing array.

6. The hand-supportable digital image capture and processing system of claim 3, wherein said LED-based illumination is reflected off the object and collected from the selected portion of said FOV to produce said electrical signal, which in turn, is used to control the driving of said LED-based illumination array at a predetermined intensity level so that said area-type image sensing array detects a digital image of the illuminated object having high image quality.

7. The hand-supportable digital image capture and processing system of claim 1, wherein said light collecting optical component comprises a light collecting mirror for focusing LED-based illumination in the selected portion of said FOV, onto said photodetector.

8. The hand-supportable digital image capture and processing system of claim 7, wherein said light collecting mirror comprises a parabolic mirror.

9. The hand-supportable digital image capture and processing system of claim 1, wherein said area-type image sensing array comprises a CMOS image sensing array.

10. The hand-supportable digital image capture and processing system of claim 1, wherein said LED-based illumination comprises narrow-band LED-based illumination.

11. The hand-supportable digital image capture and processing system of claim 1, wherein said object bears a code symbol, and said image-processing subsystem processes said digital images so as to read the code symbol and producing symbol character data representative of said read code symbol.

12. The hand-supportable digital image capture and processing system of claim 11, wherein 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.