HAND-SUPPORTABLE PLANAR LASER ILLUMINATION AND IMAGING (PLIIM) BASED CAMERA SYSTEM CAPABLE OF PRODUCING DIGITAL LINEAR IMAGES OF AN OBJECT, CONTAINING PIXELS HAVING A SUBSTANTIALLY UNIFORM ASPECT-RATIO INDEPENDENT OF THE MEASURED RELATIVE VELOCITY OF AN OBJECT WHILE MANUALLY MOVING SAID PLIIM BASED CAMERA SYSTEM PAST SAID OBJECT DURING ILLUMINATION AND IMAGING OPERATIONS

• US 7,066,391 B2
• Filed: 05/16/2002
• Issued: 06/27/2006
• Est. Priority Date: 06/07/1999
• Status: Expired due to Fees

• Current Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Original Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Inventors: Zhu, Xiaoxun, Knowles, C. Harry, Au, Ka Man, Ghosh, Sankar, Schnee, Michael D., Tsikos, Constantine J.
• Primary Examiner(s): Frech, Karl D.
• Assistant Examiner(s): Kim, Ahshik
• Application Number:
  US10/150,540
• Publication Number:
  US 20030218070A1
• Time in Patent Office: 1,503 Days
• Field of Search: 235/462.01, 235/462.22, 235/462.23, 235/462.42, 235/462.45, 235/472.01, 235/462.32
• US Class Current: 235/462.45
• CPC Class Codes: G02B 19/0014 at least one surface having optical power
• CPC Class Codes: G02B 19/0052 the light source comprising a laser diode coupling into light guides using intermediate optical elements G02B6/4204; semiconductor lasers having optical devices external to the laser cavity H01S5/005
• CPC Class Codes: G02B 19/0085 for use with both a detector and a source , e.g. in a transceiver, G02B19/009, G02B19/0095 take precedence
• CPC Class Codes: G02B 19/009 for use with infrared radiation
• CPC Class Codes: G02B 19/0095 for use with ultraviolet radiation
• CPC Class Codes: G02B 26/10 Scanning systems
• CPC Class Codes: G02B 27/095 Refractive optical elements
• CPC Class Codes: G02B 27/48 Laser speckle optics
• CPC Class Codes: G06K 7/10 by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
• CPC Class Codes: G06K 7/10594 Beam path
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/10732 Light sources
• CPC Class Codes: G06K 7/146 the method including quality enhancement steps
• CPC Class Codes: G06Q 10/00 Administration; Management
• CPC Class Codes: G06Q 30/00 Commerce
• CPC Class Codes: G06V 20/62 Text, e.g. of license plates, overlay texts or captions on TV images
• CPC Class Codes: G06V 30/144 using a slot moved over the image; using discrete sensing elements at predetermined points; using automatic curve following means
• CPC Class Codes: H01S 5/005 Optical components external to the laser cavity, specially adapted therefor, e.g. for homogenisation or merging of the beams or for manipulating laser pulses, e.g. pulse shaping H01S5/026, H01S5/18388 take precedence
• CPC Class Codes: H01S 5/02325 Mechanically integrated components on mount members or optical micro-benches
• CPC Class Codes: H01S 5/4025 Array arrangements, e.g. constituted by discrete laser diodes or laser bar H01S5/42 takes precedence

Abstract

A hand-supportable planar laser illumination and imaging (PLIIM) based camera system for producing digital linear images of a object within a working range, wherein the digital linear images contain pixels having a substantially uniform aspect-ratio independent of the measured relative velocity of the object while the PLIIM based camera system is manually moved (e.g. swept) past the object during illumination and imaging operations. The hand-supportable PLIIM based camera system comprises an object velocity measurement subsystem mounted within its hand-supportable housing, for determining the velocity of the object relative to the hand-supportable housing and generating object velocity data indicative of the determined velocity of the object. Also, a camera control computer is mounted within the hand-supportable housing, for controlling the operation of the PLIIM-based linear imaging subsystem, in automatic response to object velocity data generated by the object velocity measurement subsystem. During object illumination and imaging operations, the camera control computer (1) uses the object velocity data to determine a photo-integration time period parameter for the linear image detection array which produces digital linear images of the object, containing pixels having a substantially uniform aspect-ratio, independent of relative velocity of the object; and then (2) uses the determined photo-integration time period parameter to automatically control the operation of the linear image detection array so that the linear image detection array automatically produces digital linear images of the object, containing pixels having a substantially uniform aspect-ratio independent of the measured velocity of the moving object. By virtue of the present invention, it is now possible to produce digital images of objects containing pixels having a substantially uniform aspect-ratio, thereby satisfying the processing constraints associated with conventional 2-D bar code reading and OCR algorithms used in automatic object identification applications.

Claims

1. A hand-supportable planar laser illumination and imaging (PLIIM) based camera system for producing digital linear images of an object within a working range, wherein said digital linear images contain pixels having a substantially uniform aspect-ratio independent of the measured relative velocity of said object while said PLIIM based camera system is manually moved past said object during object illumination and imaging operations, said hand-supportable PLIIM based camera system comprising:

a hand-supportable housing having a light transmission aperture;

a PLIIM-based linear imaging subsystem mounted within said hand-supportable housing, and having

a planar laser illumination array (PLIA) including a plurality of laser diodes for producing and projecting a planar laser illumination beam (PLIB) through said light transmission aperture, so as to illuminate an object as said hand-supportable housing is manually moved past the object during object illumination and imaging operations, and

an image formation and detection (IFD) module having a linear image detection array and image forming optics for providing said linear image detection array with a field of view (FOV) which is projected through said light transmission aperture, and along which linear images of illuminated portions of said object can be detected,

wherein said PLIB and FOV are arranged in a coplanar relationship along the working range of said PLIIM based camera system so that the PLIB illuminates primarily within said FOV of the IFD module;

an object velocity measurement subsystem disposed within said hand-supportable housing, for determining the velocity of the object relative to said hand-supportable housing and generating object velocity data indicative of the determined velocity of the object;

a camera control computer, mounted within said hand-supportable housing, for controlling the operation of said PLHM-based linear imaging subsystem, in automatic response to object velocity data generated by said object velocity measurement subsystem,

wherein said camera control computer

(1) uses said object velocity data to automatically determine a photo-integration time period parameter for the linear image detection array which produces digital linear images of said object, containing pixels having a substantially uniform aspect-ratio, independent of velocity of said object; and

(2) uses said determined photo-integration time period parameter to automatically control the operation of said linear image detection array so that said linear image detection array automatically produces digital linear images of said object, containing pixels having a substantially uniform aspect-ratio independent of the measured velocity of the object.

2. The hand-supportable PLIIM based camera system of claim 1, wherein said object velocity measurement subsystem comprises:

means for projecting and scanning a light beam along the surface of said object;

means for receiving and detecting light reflected from said object;

means for generating an electrical signal representative of characteristics of said detected light;

means for processing said electrical signal to determine velocity of the object relative to said hand-supportable housing; and

means for generating object velocity data indicative of the determined velocity of the object.

3. The hand-supportable PLIIM based camera system of claim 2, wherein said object velocity measurement subsystem comprises:

means for producing a pair of laser scanning beams which are projected outside of said hand-supportable housing at different angles so as to scan the surface of said object, and produce reflected light signals which are detected and processed so as to determine the velocity of the object being illuminated and imaged; and

means for generating object velocity data indicative of the determined velocity of the object.

4. The hand-supportable PLIIM based camera system of claim 2, wherein said object velocity measurement subsystem comprises:

means for producing a pair of amplitude modulated (AM) laser scanning beams which are projected at different angles outside of said hand-supportable housing at different angles so as to scan the surface of said object, and produce reflected light signals which are detected and processed so as to determine the range and velocity of the object being illuminated and imaged; and

means for generating object range and velocity data indicative of the determined range and velocity of the object, respectively.

5. The hand-supportable PLIIM based camera system of claim 4, wherein said camera control computer controls the operation of said PLIIM-based linear imaging subsystem, in automatic response to object range and velocity data generated by said object velocity measurement subsystem, and

wherein said camera control computer

(1) uses said object range and velocity data to determine a photo-integration time period parameter for the linear image detection array which produces digital linear images of said object, containing pixels having a substantially uniform aspect-ratio, independent of range and/or velocity of said object;

and

(2) uses said determined photo-integration time period parameter to control the operation of said linear image detection array so that said linear image detection array automatically produces digital linear images of said object, containing pixels having a substantially uniform aspect-ratio independent of the measured range and/or velocity of the object.

6. The hand-supportable PLIIM based camera system of claim 1, wherein said camera control computer comprises a programmed microprocessor.

7. The hand-supportable PLIIM based camera system of claim 5, wherein said substantially uniform aspect-ratio is 1:

1representative of substantially pixels.