Planar laser illumination and imaging (PLIIM) engine
View Patent ↗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. 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 scanning applications alike, enjoying the advantages and benefits that each such technology has to offer, while avoiding the shortcomings and drawbacks hitherto associated therewith.
1. A planar laser 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, said PLIIM engine comprising:
an engine housing having a light transmission aperture;
a linear image formation and detection (IFD) module mounted within said engine housing, and having a linear image detection array with image detection elements and image formation optics having a field of view (FOV) projected through said light transmission aperture into an illumination and imaging field external to said engine housing and in which an object is presented for illumination by a planar laser illumination beam (PLIB), and a linear image of the object is formed and detected by said linear IFD module;
a pair of planar laser illumination arrays (PLIAs) mounted within said engine housing and arranged on opposite sides of said linear IFD module, each said PLIA including a plurality of planar laser illumination modules (PLIMs) for producing a plurality of spatially-incoherent planar laser illumination beam (PLIB) component which are spatially aligned to produce a planar laser illumination beam (PLIB) arranged in a coplanar relationship with a portion of said FOV, and each said PLIM including a visible laser diode and beam focusing and diverging optics for producing one said PLIB component;
an image frame grabber mounted within said engine housing, for grabbing linear images formed and detected by said linear IFD module;
an image data buffer mounted in said engine housing, for buffering said grabbed linear images; and
a controller mounted in said engine housing, for controlling said linear IFD module, and said pair of PLIAs;
whereby a series of linear images of said object are sequentially formed and detected by said linear IFD module as said engine housing moves past said object, so that said series of linear images are grabbed by said image frame grabber, and buffered in said image data buffer for subsequent processing.
2. The PLIIM engine of claim 1 , which further comprises an image processing computer in operable communication with said image data buffer for receiving and processing said linear images.
3. The PLIIM engine of claim 2 , wherein said image processing computer receives and processes a series of buffered linear images so as to compose a two-dimensional image, and then processes said two-dimensional image so as to decode a 1-D or 2-D bar code symbol structure represented within the structure of said two-dimensional image.
4. The PLIIM engine of claim 2 , wherein said image processing computer receives and processes a series of buffered linear images so as to compose a two-dimensional image, and then processes said two-dimensional image so as to recognize character strings or other forms of graphical intelligence represented within the structure of said two-dimensional image.
5. The PLIIM engine of claim 1 , wherein said image formation optics have a fixed focal distance and a fixed focal length providing a fixed field of view (FOV).
6. The PLIIM engine of claim 1 , wherein said image formation optics have a variable focal distance and a fixed focal length providing a fixed field of view (FOV).
7. The PLIIM engine of claim 1 , wherein said image formation optics have a variable focal distance and a variable focal length providing a variable field of view (FOV).
8. A planar laser 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, said PLIIM engine comprising:
a linear image formation and detection (IFD) module mounted on a support platform, and having a linear image detection array with image detection elements and image formation optics having a field of view (FOV) projectable into an illumination and imaging field in which an object is presented for illumination by a planar laser illumination be (PLIB), and a linear image of the object is formed and detected by said linear IFD module;
a pair of planar laser illumination arrays (PLIAs) mounted on said support platform and arranged on opposite sides of said linear IFD module, each said PLIA including a plurality of planar laser illumination modules (PLIMs) for producing a plurality of spatially-incoherent planar laser illumination beam (PLIB components which are spatially aligned to produce a planar laser illumination beam (PLIB) arranged in a coplanar relationship with a portion of said FOV, and each said PLIM including a laser diode and beam focusing and diverging optics for producing one said PLIB component;
an image frame grabber for grabbing images formed and detected by said linear IFD module;
an image data buffer for buffering said grabbed linear images; and
a controller for controlling said linear IFD module, and said pair of planar laser illumination arrays;
whereby a series of linear images of said object are sequentially formed and detected by said linear IFD module as said PLIIM engine moves past said object, so that said series of linear images are grabbed by said image frame grabber, and buffered in said image data buffer for subsequent processing.
9. The PLIIM engine of claim 8 , which further comprises an image processing computer operably associated with said image data buffer, for receiving and processing said linear images.
10. The PLIIM engine of claim 9 , wherein said image processing computer receives and processes a series of buffered linear images so as to compose a two-dimensional image, and then processes said two-dimensional image so as to decode a 1-D or 2-D bar code symbol structure represented within the structure of said two-dimensional image.
11. The PLIIM engine of claim 9 , wherein said image processing computer receives and processes a series of buffered linear images so to compose a two-dimensional image, and then processes said two-dimensional image so as to recognize character strings or other forms of graphical intelligence represented within the structure of said two-dimensional image.
12. The PLIIM engine of claim 8 , wherein said image formation optics have a fixed focal distance and a fixed focal length providing a fixed field of view (FOV).
13. The PLIIM engine of claim 8 , wherein said image formation optics have a variable focal distance and a fixed focal length providing a fixed field of view (FOV).
14. The PLIIM engine of claim 8 , wherein said image formation optics have a variable focal distance and a variable focal length providing a variable field of view (FOV).
15. A planar laser 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, said PLIIM engine comprising:
an engine housing having a light transmission aperture;
a linear image formation and detection (IFD) module mounted within said engine housing, and having a linear image detection array with image detection elements and image formation optics having a field of view (FOV) projected through said light transmission aperture into an illumination and imaging field external to said engine housing and in which an object is presented for illumination by a planar laser illumination beam (PLIB) and a linear image of the object is formed and detected by said linear IFD module;
a pair of planar laser illumination arrays (PLIAs) mounted within said engine housing and arranged on opposite sides of said linear IFD module, each said PLIA including a plurality of planar laser illumination modules (PLIMs) for producing a plurality of spatially-incoherent planar laser illumination beam (PLIB) components which are spatially aligned to produce a planar laser illumination beam (PLIB arranged in a coplanar relationship with a portion of said FOV, and each said PLIM including a visible laser diode and beam focusing and diverging optics for producing on said PLIB component;
an image frame grabber mounted within said engine housing, for grabbing images formed and detected by said linear IFD module;
an image data buffer mounted in said engine housing, for buffering said grabbed linear images; and
a controller mounted in said engine housing, for controlling said linear IFD module, and said pair of PLIAs;
whereby a series of linear images of said object are sequentially formed and detected by said linear IFD module as said engine housing moves past said object, so that said series of linear images are grabbed by said image frame grabber, and buffered in said image data buffer for subsequent processing; and
an image processing computer mounted within said engine housing, and in operable communication with said image data buffer, for receiving and processing said linear images.
16. The PLIIM engine of claim 15 , wherein said image processing computer receives and processes a series of buffered linear images so as to compose a two-dimensional image, and then processes said two-dimensional image so as to decode a 1-D or 2-D bar code symbol structure represented within the structure of said two-dimensional image.
17. The PLIIM engine of claim 15 , wherein said image processing computer receives and processes a series of buffered linear images so as to compose a two-dimensional image, and then processes said two-dimensional image so as to recognize character strings or other forms of intelligence represented within the structure of said two-dimensional image.
18. The PLIIM engine of claim 15 , wherein said image formation optics have a fixed focal distance and a fixed focal providing a fixed field of view (FOV).
19. The PLIIM engine of claim 18 , wherein said image formation optics have a variable focal distance and a fixed focal length providing a fixed field of view (FOV).
20. The PLIIM engine of claim 18 , wherein said image formation optics have a variable focal distance and a variable focal length providing a variable field of view (FOV).