Abstract:
Methods of and systems for illuminating objects using planar laser illumination beams having substantially-planar spatial distribution characteristics that extend through the field of view (FOV) of image formation and detection modules employed in such systems. Each planar laser illumination beam is produced from a planar laser illumination beam array (PLIA) comprising an plurality of planar laser illumination modules (PLIMs). Each PLIM comprises a visible laser diode (VLD, a focusing lens, and a cylindrical optical element arranged therewith. The individual planar laser illumination beam components produced from each PLIM are optically combined to produce a composite substantially planar laser illumination beam having substantially uniform power density characteristics over the entire spatial extend thereof and thus the working range of the system. Preferably, each planar laser illumination beam component is focused so that the minimum beam width thereof occurs at a point or plane which is the farthest or maximum object distance at which the system is designed to acquire images, thereby compensating for decreases in the power density of the incident planar laser illumination beam due to the fact that the width of the planar laser illumination beam increases in length for increasing object distances away from the imaging optics. Advanced high-resolution wavefront control methods and devices are disclosed for use with the PLIIM-based systems in order to reduce the power of speckle-noise patterns observed at the image detections thereof. By virtue of the present invention, it is now possible to use both VLDs and high-speed CCD-type image detectors in conveyor, hand-held and hold-under type imaging applications alike, enjoying the advantages and benefits that each such technology has to offer, while avoiding the shortcomings and drawbacks hitherto associated therewith.
Abstract:
A hand-supportable planar laser illumination and imaging (PLIIM) based code symbol reader includes: a hand-supportable housing having light transmission aperture; a linear image formation and detection module having a linear image detection array; and a planar laser illumination beam (PLIB) producing device having at least one visible laser diode (VLD) for producing a planar light illumination beam (PLIB). The code symbol reader further includes image grabber for grabbing digital linear images formed and detected by the image formation and detection module, an image data buffer for buffering the digital linear images grabbed by the image grabber and constructing a two-dimensional image from a series of buffered linear digital images, and an image processing computer for processing the buffered two-dimensional digital image so as to read code symbols graphically represented in the two-dimensional digital linear image. During object illumination and imaging operations, a controller automatically controls the linear image formation and detection module, the PLIB producing device, the image frame grabber, and the image data buffer.
Abstract:
Illumination apparatus for forming an output beam, the apparatus comprising: (a) a light source adapted to emit a source beam of linearly-polarized light in a downstream direction along an optical axis, said source beam having a polarization direction transverse to said optical axis; and (b) a fixed birefringent plate having first and second regions with different rotational properties such that said first region of said plate intercepts a first portion of said source beam and said second region intercepts a second portion of said source beam, said first and second regions altering the polarization of said first and second portions of said source beam by different amounts so as to form an altered beam having a central portion with a first polarization direction and a peripheral portion with a second polarization direction transverse to said first polarization direction, said peripheral portion surrounding said central portion, said central portion having a first intensity distribution relative to said optical axis, said peripheral portion having a second intensity distribution relative to said optical axis; and (c) at least one polarization-selective element mounted downstream from said birefringent plate, said at least one polarization-selective element having a transmission axis and being operative to allow transmission of light having a polarization direction parallel to such transmission axis and to prevent transmission of light having a polarization direction perpendicular to such transmission axis.
Abstract:
An Internet-based remote monitoring, configuration and service (RMCS) system capable of monitoring, configuring and servicing a planar laser illumination and imaging (PLIIM) based network. The network has one or more nodes and performs object identification and attribute acquisition functions. Each node is a PLIIM-based subsystem operably connected to a digital communications network interconnectable to the infrastructure of the Internet. The Internet-based RMCS system comprises a monitoring subsystem for remotely monitoring a set parameters associated with the PLIIM-based network. The set of parameters relate to network, system and/or subsystem characteristics of the PLIIM-based network. The RMCS also includes an analyzing subsystem for remotely analyzing the parameters to diagnose (i) performance failures in the PLIIM-based network, as well as (ii) the operation and performance of the PLIIM-based network. The RMCS also includes a control subsystem for remotely controlling one or more of the parameters so as to improve the performance of the PLIIM-based network and/or provide service thereto from a remote location.
Abstract:
Illumination apparatus includes a light source which directs a polarized source beam in a downstream direction along an optical axis and desirably focuses the beam. A polarization-altering element downstream from the source such as a birefringent plate alters the polarization in a portion or portions of the source beam, so that the altered beam includes portions having different polarization directions. The altered beam passes downstream through a polarization-selective filter. The output beam from the polarization-selective filter can include either portion depending on the orientation of the filter. The arrangement can be used to provide a spot of a given size and shape at the focal location in a scanner such as a bar code scanner. The size and depth of field of the spot can be varied dynamically during operation.
Abstract:
A hand-supportable planar laser illumination and imaging (PLIIM) based code symbol reader includes: a hand-supportable housing having light transmission aperture; a linear image formation and detection module having a linear image detection array; and a planar laser illumination beam (PLIB) producing device having at least one visible laser diode (VLD) for producing a planar light illumination beam (PLIB). The code symbol reader further includes image grabber for grabbing digital linear images formed and detected by the image formation and detection module, an image data buffer for buffering the digital linear images grabbed by the image grabber and constructing a two-dimensional image from a series of buffered linear digital images, and an image processing computer for processing the buffered two-dimensional digital image so as to read code symbols graphically represented in the two-dimensional digital linear image. During object illumination and imaging operations, a controller automatically controls the linear image formation and detection module, the PLIB producing device, the image frame grabber, and the image data buffer.
Abstract:
A planar laser illumination and imaging (PLIIM) based engine including; an engine housing having light transmission aperture; an image formation and detection module and having an image detection array and image formation optics with a field of view (FOV) extending from the image detection array, through the light transmission aperture and onto an object moving relative to the engine housing during object illumination and imaging operations; a planar laser illumination beam (PLIB) producing device, and having at least one visible laser illumination source arranged in relation to the image formation and detection module, for producing a planar light illumination beam (PLIB), and projecting the planar light illumination beam through light transmission aperture and oriented such that the plane of the PLIB is coplanar with the field of view of the image formation and detection module so that the object can be simultaneously illuminated by the planar light illumination beam and imaged within the field of view and onto the image detection array for detection as a digital linear image of the object; a laser despeckling mechanism for reducing the coherence of the PLIB during object illumination and imaging operation so that the power of speckle-pattern noise is substantially reduced in digital linear images detected on said image detection array.
Abstract:
A tunnel-type digital imaging system for use within retail shopping environments such as supermarkets. The system includes a tunnel configuration arranged about a conveyor structure for transporting objects therethrough, and an image capturing and processing subsystem embodied within the tunnel configuration, for generating a 3D digital imaging volume above the conveyor structure and within the tunnel configuration, for capturing digital images of objects transported through the 3D imaging volume. The image capturing and processing subsystem includes a plurality of coplanar illumination and imaging stations. Each station includes a linear imaging array having optics providing a field of view (FOV) on the linear imaging array that is projected and extends into the 3D imaging volume, and one or more light emitting devices configured together to produce a substantially planar illumination beam (PLIB) that extends in substantially along the same plane as the FOV of the linear imaging array so that each the linear imaging array and corresponding one or more light emitting devices produce at least one coplanar illumination and imaging plane that projects into the 3D imaging volume. A digital image processing subsystem processing digital images of objects passing through the 3D imaging volume, and a system control subsystem controls and/or orchestrates the coplanar illumination and imaging subsystems during system operation.
Abstract:
A LED-based planar light illumination and imaging (PLIIM) engine for use in a hand-supportable linear imager adapted for manual movement relative to an object to be illuminated and imaged. The LED-based PLIIM engine comprises an engine housing having a light transmission aperture, and a linear image formation and detection (IFD) module having a linear image detection array with image detection elements and image formation optics having a field of view (FOV) projected through the light transmission aperture into an illumination and imaging field, in which an object is presented for illumination and imaging. A pair of planar light illumination arrays (PLIAs) are arranged on opposite sides of the linear IFD module. Each PLIA includes a plurality of planar light illumination modules (PLIMs) for producing a plurality of spatially-incoherent planar light illumination beam (PLIB) components which are spatially aligned to produce a planar light illumination beam (PLIB) arranged in a coplanar relationship with a portion of the FOV. Each PLIM includes a light emitting diode (LED) and beam focusing and diverging optics for producing one PLIB component. An image frame grabber is provided for grabbing images formed and detected by the linear IFD module. An image data buffer is provided for buffering the grabbed linear images. A controller is provided for controlling the linear IFD module, and the pair of planar light illumination arrays. As the engine housing moves past the object, a series of linear images of the object are sequentially detected by the linear IFD module, grabbed by the image frame grabber, and buffered in the image data buffer for subsequent processing by an image processing computer, so to decode a 1-D or 2-D bar code symbol structure represented within the structure of said two-dimensional image, or recognize character strings or other forms of graphical intelligence represented therewithin.
Abstract:
A hand-supportable bar code symbol reading device having a laser scanning engine that is controlled to selectively operate in either an omni-directional scan mode or a single line scan mode. In the single line scan mode of operation, symbol character data produced by the laser scanning engine is communicated to a host device in response to an activation signal produced by a data transmission switch. In the omni-directional scan mode, symbol character data is communicated to the host device irrespective of the activation signal. Preferably, mode selection means selectively operates the laser scanning engine in either the omni-directional scan mode of operation or the single line scan mode of operation in response to placement of the device in a support stand, thereby enabling automatic operation as a stationary hands-free omni-directional projection scanner (in stand), and automatic operation as a portable hand-held line scanner (out of stand).