Abstract:
A barcode scanner which uses different wavelengths of light to produce different fields of view. An example barcode scanner includes a plurality of light devices each having a different wavelength of light and each associated with a different field of view for illuminating an item with a barcode, a plurality of waveband mirrors each reflecting one of the different wavelengths of light from the light devices and transmitting other wavelengths of light, an imager for receiving the different wavelengths of light reflected from the waveband mirrors and for producing corresponding images, and a controller configured to sequentially activate the light devices and the imager and to decode the barcode in an at least one of the images received from the imager.

Description:
BACKGROUND 
       [0001]    This present invention relates to barcode scanners and more specifically to an imaging barcode scanner with multiple independent fields of view. 
         [0002]    Barcode scanners are well known for their usefulness in retail checkout and inventory control. An imaging barcode scanner includes one or more digital image sensors or imagers to capture images of an item, including a barcode on the item. 
         [0003]    Some barcode scanners used in checkout environments are capable of reading a barcode on an item from multiple directions. These multi-aperture barcode scanners may include a horizontal aperture that is substantially flush with the checkout counter and a vertical aperture in a “tower” portion that extends upwards from the checkout counter. 
         [0004]    Current multi-aperture imaging barcode scanners use multiple imagers and/or mirrors that split the camera&#39;s field of view into several smaller fields of view (FOV). The splitting of the FOV reduces scanning performance by not only reducing the size of the scan zone, but also having to stitch together pieces of barcodes which no longer fit within a full sized FOV. 
         [0005]    Therefore, it would be desirable to provide an imaging barcode scanner with enhanced performance that does not split the imager&#39;s field of view. 
       SUMMARY 
       [0006]    In accordance with the teachings of the present invention, an imaging barcode scanner with multiple independent fields of view is provided. 
         [0007]    An example barcode scanner includes a plurality of light devices each having a different wavelength of light and each associated with a different field of view for illuminating an item with a barcode, a plurality of waveband mirrors each reflecting one of the different wavelengths of light from the light devices and transmitting other wavelengths of light, an imager for receiving the different wavelengths of light reflected from the waveband mirrors and for producing corresponding images, and a controller configured to sequentially activate the light devices and the imager and to decode the barcode in an at least one of the images received from the imager. 
         [0008]    An example scanning method includes sequentially activating a plurality of light devices each having a different wavelength of light and each associated with a different field of view to illuminate an item with a barcode, reflecting at least one of the different wavelengths of light towards an imager by a waveband mirror, producing an image from the one wavelength of light by the imager; and decoding the barcode in the image. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The present invention may take form in various components and arrangement of components and in various methods. The drawings are only for purposes of illustrating example embodiments and alternatives and are not to be construed as limiting the invention. 
           [0010]      FIG. 1  is a block diagram of an example barcode scanner. 
           [0011]      FIG. 2  illustrates an example configuration of the barcode scanner that produces multiple different fields of view. 
           [0012]      FIG. 3  is a perspective view of one example barcode scanner. 
           [0013]      FIG. 4  further illustrates an example positioning of the example configuration within the example barcode scanner of  FIG. 3 . 
           [0014]      FIG. 5  illustrates an example mirror configuration associated with a first field of view of the example barcode scanner. 
           [0015]      FIG. 6  illustrates an example mirror configuration associated with a second field of view of the example barcode scanner. 
           [0016]      FIG. 7  illustrates an example mirror configuration associated with a third field of view of the example barcode scanner. 
           [0017]      FIG. 8  illustrates an example mirror configuration associated with a fourth field of view of the example barcode scanner. 
           [0018]      FIG. 9  illustrates another example configuration of the barcode scanner that produces multiple different fields of view. 
           [0019]      FIG. 10  illustrates another example configuration of the barcode scanner that produces multiple different fields of view. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    Referring now to  FIG. 1 , an example barcode scanner  10  includes controller  12 , imager  14 , waveband mirrors  16 , folding mirrors  18 , and light devices  20 . 
         [0021]    Controller  12  controls operation of barcode scanner  10 , including controlling illumination of items  22  by light devices  20 , activation of imager  14  in synchronism with illumination, and processing of images received from imager  14 . Processing of images may include identifying barcodes  24  in the images and decoding the barcodes  24 . Controller  12  sends decoded barcode information, including item identification information, to point of sale (POS) terminal, which adds obtains price information for items  22  and adds items  22  to a transaction. 
         [0022]    Imager  14  captures images of items  22  during scanning. Imager  14  may include a sensor with a Charge Coupled Device (CCD) or Complementary Metal-Oxide-Semiconductor (CMOS) with pixel elements that convert light to electrical signals that contain color information. 
         [0023]    Waveband mirrors  16  each reflect a different waveband of illumination and transmit other wavelengths. An example of such a mirror would be either a “long” or “short” pass mirror from Edmund Scientific, CVI, Melles Griot, or Rolyn Optics. Custom waveband mirrors may come from JDSU, Barr Associates, or Esco Products. 
         [0024]    Folding mirrors  18  direct light reflected from items  22  to waveband mirrors  16 . 
         [0025]    Light devices  20  each emit light at different wavelengths (or different wavelength bands). Each light device  20  is associated with a different field of view (FOV). Controller  12  synchronizes activation of light devices  20  with the frame rate of imager  14  and pulses light devices  20  sequentially in a repeatable order so that imager  14  only sees light from one light device  20  and one corresponding FOV at any instant in time and produces one or more corresponding images. Light devices  20  may include narrow band light emitting diodes (LEDs). 
         [0026]    Barcode scanner  10  may further include scale  28  for measuring weights of items  22 . For example, when item  22  is a produce item, scale  28  provides weight information to controller  12 , which passes the weight information to POS terminal  26  to obtain pricing information and add the produce item to the transaction. 
         [0027]    With reference to  FIG. 2 , and example configuration is illustrated which produces four different and independent FOVs  30 A- 30 D and uses a single imager  14 . Other configurations with other numbers of FOVs  30  and imagers  14  are also envisioned. 
         [0028]    Waveband mirror  16 A is oriented at a first angle with respect to imager  14  to produce a first FOV  30 A by reflecting from a first direction light from light device  20 A towards imager  14 . Waveband mirror  16 A is transparent to other wavelengths of light, including light from light devices  20 B- 20 D. 
         [0029]    Waveband mirror  16 B is oriented adjacent waveband mirror  16 A at a second angle with respect to imager  14  to produce a second FOV  30 B by reflecting from a second direction light from light device  20 B towards imager  14 . Waveband mirror  16 B is transparent to other wavelengths of light, including light from light devices  20 C- 20 D. 
         [0030]    Waveband mirror  16 C is oriented adjacent waveband mirror  16 B at a third angle with respect to imager  14  to produce a third FOV  30 C by reflecting from a third direction light from light device  20 C towards imager  14 . Waveband mirror  16 C is transparent to other wavelengths of light, including light from light devices  20 D. 
         [0031]    A fourth FOV  30 D results when reflecting from a fourth direction light from light device  20 D towards imager  14 . Waveband mirrors  16 A- 16 C are transparent to light from light device  20 D. 
         [0032]    Light devices  20 A- 20 D are positioned to sequentially illuminate all sides of item  22  during scanning. In one example embodiment, light devices  20 A- 20 D are mounted adjacent to imager  14  on a common printed circuit board. In this configuration, light from light device  20 A reflects from waveband mirror  16 A, light from light device  20 B passes through waveband mirror  16 A and reflects from waveband mirror  16 A, light from light device  20 C passes through waveband mirrors  16 A- 16 B and reflects from waveband mirror  16 C, and light from light device  20 D passes through waveband mirrors  16 A- 16 C without reflection. 
         [0033]    In another configuration, light devices  20 A- 20 D are mounted separately from imager  14 , but internal to the scanner housing. 
         [0034]    In another configuration, light devices  20 A- 20 D are mounted externally on the housing of barcode scanner  10 . Combinations of all three configurations are also envisioned. 
         [0035]    With reference to  FIG. 3 , example barcode scanner  10  includes a lower portion  40  with a substantially horizontal window  46  and an upper or “tower” portion  42  with a substantially vertical aperture  44 . When equipped with scale  28 , example barcode scanner  10  includes scale weigh plate  48 , which has its own window  50 . 
         [0036]    Referring now to  FIG. 4 , imager  14  and waveband mirrors  16 A-C are located along a longitudinal line within lower portion  40 . Waveband mirrors  16 A- 16 C may be the same size or be progressively larger in size with distance away from imager  14   
         [0037]    With the addition of folding mirrors  18 , a barcode scanner  10  that has the example configuration can scan a barcode on item  22  from any direction (“six-sided” scanning when item  22  has a box-like shape), regardless of the orientation of item  22  with respect to barcode scanner  10 . A single imager  14  may be used, since this configuration does not split any FOVs  30 , though other configurations are envisioned which use more than one imager  14 . Independent FOVs  30 A- 30 D combine to form the scan volume of barcode scanner  10 , using only three waveband mirrors  16 A-C to produce six-sided scanning. Other configurations and numbers of waveband mirrors are also envisioned. 
         [0038]    Referring now to  FIG. 5 , folding mirrors  18 A- 1  and  18 A- 2  are located in lower portion  40  and direct light from light device  20 A that is reflected from a leading side of item  22  through aperture  46 . Folding mirror  18 A- 2  is located on one side of lower portion  40  and tilted to redirect the light from the leading edge of item  22  to folding mirror  18 A- 1 . Folding mirror  18 A- 1  is tilted so as to direct the light from folding mirror  18 A- 2  to waveband mirror  16 A. 
         [0039]    Referring now to  FIG. 6 , folding mirrors  18 B- 1  and  18 B- 2  are located in lower portion  40  and direct light from light device  20 B that is reflected from a trailing side of item  22  through aperture  46 . Folding mirror  18 B- 2  is located on a side of lower portion  40  opposite folding mirror  18 A- 2  and tilted to redirect the light from the trailing edge of item  22  to folding mirror  18 B- 1 . Folding mirror  18 B- 1  is tilted so as to direct the light from folding mirror  18 B- 2  to waveband mirror  16 B. 
         [0040]    Referring now to  FIG. 7 , folding mirror  18 C is located in upper portion  42  and directs light from light device  20 C that is reflected from a top side of item  22  and a tower-facing side of item  22  through aperture  44 . Folding mirror  18 C is tilted to redirect the light from the top side of item  22  to waveband mirror  16 C. 
         [0041]    Referring now to  FIG. 8 , folding mirror  18 D is located in lower portion  40  and directs light from light device  20 D that is reflected from a bottom side of item  22  and from an operator-facing side of item  22  through aperture  46 . Folding mirror  18 D is tilted to redirect the light from the bottom and operator-facing sides of item  22  through waveband mirrors  16 A- 16 C to imager  14 . 
         [0042]      FIGS. 9 and 10  contain alternate embodiments illustrating other ways to position and orient waveband mirrors  16 A- 16 C within the scanner housing.  FIG. 9  illustrates waveband mirrors  16 A- 16 C oriented vertically within the tower portion  42 .  FIG. 10  illustrates waveband mirrors  16 A- 16 C oriented horizontally, but substantially perpendicular to the orientation in  FIGS. 5-8 . 
         [0043]    Advantageously, the example configurations result in improved performance and the captured spectral content may provide additional information for product &amp; produce recognition. 
         [0044]    Although the present invention has been described with particular reference to certain preferred embodiments thereof, variations and modifications of the present invention can be effected within the spirit and scope of the following claims.