Patent Publication Number: US-2012031975-A1

Title: Illumination blocks for a graphical code reader

Description:
BACKGROUND 
     A machine-readable graphical code (“graphical code”) is a graphical representation of information that consists of multiple graphical code elements having different light reflective or light emissive properties. Examples of different types of graphical codes include bar codes, data matrix codes, MaxiCodes, and so forth. Graphical codes and graphical code readers have become widely used in many commercial environments, such as point-of-sale stations in retail stores and supermarkets, inventory and document tracking, and the like. 
     Devices for identifying or extracting information from graphical codes are generally referred to as graphical code readers. Some graphical code readers include an imaging engine. As used herein, the term “imaging engine” refers to a combination of hardware and optical components that collectively function to capture two-dimensional images of graphical codes. During typical operation, one or more light sources within the imaging engine illuminate a target area in which a graphical code may be located. Light is reflected from the graphical code toward the graphical code reader. One or more lenses within the imaging engine focus an image of the graphical code onto an image sensor. Pixels within the image sensor are read electronically to provide a two-dimensional array of image data corresponding to the graphical code. A decoder then processes the image data and extracts the information that is contained in the graphical code. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a system for reading graphical codes in accordance with the present disclosure; 
         FIG. 2  illustrates another system for reading graphical codes in accordance with the present disclosure; 
         FIG. 3  illustrates another system for reading graphical codes in accordance with the present disclosure; and 
         FIG. 4  illustrates another system for reading graphical codes in accordance with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a system  100  for reading graphical codes in accordance with the present disclosure. The system  100  includes a graphical code reader (“reader”)  102 . The reader  102  includes an imaging engine  104 . The imaging engine  104  includes two light sources  106   a - b . (The number of light sources  106  is for purposes of example only; a different number of light sources  106  may be used.) The light sources  106   a - b  may be light-emitting diodes (LEDs). 
     The imaging engine  104  also includes illumination control circuitry  110  that is configured to activate the light sources  106   a - b . Activating the light sources  106   a - b  may involve generating pulse width modulation signals for the light sources  106   a - b . The illumination control circuitry  110  may be separate from the imaging engine  104 , as shown. Alternatively, the illumination control circuitry  110  may be included within the imaging engine  104 . 
     The system  100  also includes illumination blocks  112   a - f  and supplemental light sources  108   a - f . The supplemental light sources  108   a - f  may be LEDs. Each illumination block  112  includes a supplemental light source  108 . (The number of illumination blocks  112  within the system  100  and the number of supplemental light sources  108  within each illumination block  112  is for purposes of example only; a different number of illumination blocks  112  and/or supplemental light sources  108  may be used.) 
     The illumination blocks  112   a - f  are removably connected to the reader  102 . In other words, although  FIG. 1  shows the illumination blocks  112   a - f  as being connected to the reader  102 , some or all of the illumination blocks  112   a - f  may be disconnected from the reader  102  and the reader  102  may operate without them. 
     As mentioned, the illumination control circuitry  110  is configured to activate the imaging engine&#39;s light sources  106   a - b . In addition, the illumination control circuitry  110  is also configured to activate the supplemental light sources  108   a - f  when the illumination blocks  112   a - f  are connected to the reader  102 . 
     There are some situations in which the imaging engine&#39;s light sources  106   a - b  may provide sufficient illumination for reading graphical codes. In these situations, the reader  102  may be used without the illumination blocks  112   a - f . However, there may also be situations in which additional illumination (beyond that provided by the imaging engine&#39;s light sources  106   a - b ) may be helpful in order to more accurately read graphical codes. In these situations, the illumination blocks  112   a - f  may be connected to the reader  102  and used together with the imaging engine&#39;s light sources  106   a - b.    
       FIG. 2  illustrates another system  200  for reading graphical codes in accordance with the present disclosure. The system  200  of  FIG. 2  is similar to the system  100  that was discussed above in connection with  FIG. 1 , except as indicated below. 
     In the depicted system  200 , each illumination block  212  includes a supplemental light source  208  and illumination control circuitry  214  that is configured to activate the supplemental light source  208 . Thus, the system  200  includes illumination blocks  212   a - f , supplemental light sources  208   a - f  (which may be LEDs), and illumination control circuitry  214   a - f  for the supplemental light sources  208   a - f . (The number of illumination blocks  212  within the system  200  and the number of supplemental light sources  208  within each illumination block  212  is for purposes of example only; a different number of illumination blocks  212  and/or supplemental light sources  208  may be used.) 
     In order to distinguish the illumination control circuitry  210  for the imaging engine&#39;s light sources  206   a - b  from the illumination control circuitry  214   a - f  for the supplemental light sources  208   a - f , the illumination control circuitry  210  for the imaging engine&#39;s light sources  206   a - b  will be referred to as reader illumination control circuitry  210 , whereas the illumination control circuitry  214   a - f  for the supplemental light sources  208   a - f  will be referred to as illumination block control circuitry  214   a - f.    
     The reader  202  also includes communication circuitry  216 . The communication circuitry  216  is configured to instruct the reader illumination control circuitry  210  to activate the imaging engine&#39;s light sources  206   a - b . The reader illumination control circuitry  210  is configured to activate the imaging engine&#39;s light sources  206   a - b  in response to the instructions from the communication circuitry  216  of the reader  202 . 
     The communication circuitry  216  is also configured to instruct the illumination block control circuitry  214   a - f  to activate the supplemental light sources  208   a - f  (when the illumination blocks  212   a - f  are connected to the reader  202 ). The illumination block control circuitry  214   a - f  is configured to activate the supplemental light sources  208   a - f  in response to the instructions from the communication circuitry  216  of the reader  202 . 
     The reader  202  and the first, second, and third illumination blocks  212   a - c  are serially connected. Thus, it may be said that the first, second, and third illumination blocks  212   a - c  form a first serial chain  218   a  of illumination blocks  212   a - c . Similarly, the reader  202  and the fourth, fifth, and sixth illumination blocks  212   d - f  are also serially connected. Thus, it may be said that the fourth, fifth, and sixth illumination blocks  212   d - f  form a second serial chain  218   b  of illumination blocks  212   d - f.    
     All of the illumination blocks  212  within a particular serial chain  218  receive the same instructions from the reader  202 . For example, the reader  202  is able to send instructions to cause the activation of all of the supplemental light sources  208   a - c  in the first serial chain  218   a  at the same time. However, the reader  202  is not able to send instructions to cause the activation of only the first supplemental light source  208   a  without also causing the activation of the second and third supplemental light sources  208   b - c.    
     The illumination blocks  212   a - c  in the first serial chain  218   a  may receive different instructions from the reader  202  than the illumination blocks  212   d - f  in the second serial chain  218   b . For example, the reader  202  may send activation instructions to the first serial chain  218   a  without also sending activation instructions to the second serial chain  218   b , and vice versa. 
     There are some situations in which the imaging engine&#39;s light sources  206   a - b  may provide sufficient illumination for reading graphical codes. In these situations, the reader  202  may be used without the illumination blocks  212   a - f . However, there may also be situations in which additional illumination (beyond that provided by the imaging engine&#39;s light sources  206   a - b ) may be helpful in order to more accurately read graphical codes. In these situations, the illumination blocks  212   a - f  may be connected to the reader  202  and used together with the imaging engine&#39;s light sources  206   a - b.    
     Advantageously, additional illumination blocks  212  can be connected to either serial chain  218   a - b  without making any modifications to the reader  202 . This provides a user of the reader  202  with a great deal of flexibility. The user is able to easily experiment with using different numbers of illumination blocks  212  until the amount of illumination is optimized for the particular environment in which the reader  202  is being used. When additional illumination blocks  212  are connected to a particular serial chain  218 , the additional illumination blocks  212  receive the same instructions from the reader  202  as the other illumination blocks  212  in the chain  218 . For example, if one or more additional illumination blocks  212  were connected to the first serial chain  218   a , they would receive the same instructions from the reader  202  as the other illumination blocks  212   a - c  in the chain  218   a.    
     In the depicted system  200 , the illumination control circuitry  210  is included within the imaging engine  204 . Alternatively, the illumination control circuitry  210  may be separate from the imaging engine  204 . 
       FIG. 3  illustrates a system  300  for reading graphical codes according to another embodiment of the invention. The system  300  of  FIG. 3  is similar to the system  200  that was discussed above in connection with  FIG. 2 , except as indicated below. 
     In the depicted system  300 , different supplemental light sources  308  emit different wavelengths of light. In particular, the first, second, fifth, and sixth supplemental light sources  308   a ,  308   b ,  308   e ,  308   f  emit light within a first range of wavelengths λ 1 -λ 2 . The third, fourth, seventh, and eighth supplemental light sources  308   c ,  308   d ,  308   g ,  308   h  emit light within a second range of wavelengths λ 3 -λ 4 . 
     The reader  302  is configured for at least two modes of operation. During a first mode of operation, the supplemental light sources  308   a ,  308   b ,  308   e ,  308   f  that emit light within the first range of wavelengths λ 1 -λ 2  are activated, while the supplemental light sources  308   c ,  308   d ,  308   g ,  308   h  that do not emit light within the first range of wavelengths λ 1 -λ 2  are not activated. During a second mode of operation, the supplemental light sources  308   c ,  308   d ,  308   g ,  308   h  that emit light within the second range of wavelengths λ 3 -λ 4  are activated, while the supplemental light sources  308   a ,  308   b ,  308   e ,  308   f  that do not emit light within the second range of wavelengths λ 3 -λ 4  are not activated. 
     For example, the first range of wavelengths λ 1 -λ 2  may correspond to ultraviolet light, and the second range of wavelengths λ 3 -λ 4  may correspond to red light. The reader  302  may be configured for a first mode of operation in which the supplemental light sources  308   a ,  308   b ,  308   e ,  308   f  that emit ultraviolet light are activated (e.g., for reading the watermark on paper money). The reader  302  may be configured for a second mode of operation in which the supplemental light sources  308   c ,  308   d ,  308   g ,  308   h  that emit red light are activated (e.g., for reading graphical codes). 
     The illumination blocks  312   a - d  include reporting circuitry  320   a - d  that is configured to report to the reader  302  about characteristics of the supplemental light sources  308   a - h . The reporting circuitry  320  in a particular illumination block  312  is configured to report to the reader  302  about characteristics of the supplemental light sources  308  that are included in that illumination block  312 . For example, the reporting circuitry  320   a  in the first illumination block  312   a  is configured to report to the reader  302  about characteristics of the supplemental light sources  308   a - b  that are included in the first illumination block  312   a.    
     The reader  302  is configured to receive the reports from the illumination blocks  312   a - d . The reader  302  includes selection circuitry  322 . The selection circuitry  322  is configured to identify the supplemental light sources  308   a ,  308   b ,  308   e ,  308   f  that emit light within the first range of wavelengths λ 1 -λ 2  and the supplemental light sources  308   c ,  308   d ,  308   g ,  308   h  that emit light within the second range of wavelengths λ 3 -λ 4  based on the reports from the illumination blocks  312   a - d.    
     When the reader  302  is in the first mode of operation described above, the communication circuitry  316  sends activation instructions only to the illumination block control circuitry  314   a ,  314   c  corresponding to the supplemental light sources  308   a ,  308   b ,  308   e ,  308   f  that emit light within the first range of wavelengths λ 1 -λ 2 . The communication circuitry  316  does not send activation instructions to the illumination block control circuitry  314   b ,  314   d  corresponding to the supplemental light sources  308   c ,  308   d ,  308   g ,  308   h  that emit light within the second range of wavelengths λ 3 -λ 4 . 
     Conversely, when the reader  302  is in the second mode of operation described above, the communication circuitry  316  sends activation instructions only to the illumination block control circuitry  314   b ,  314   d  corresponding to the supplemental light sources  308   c ,  308   d ,  308   g ,  308   h  that emit light within the second range of wavelengths λ 3 -λ 4 . The communication circuitry  316  does not send activation instructions to the illumination block control circuitry  314   a ,  314   c  corresponding to the supplemental light sources  308   a ,  308   b ,  308   e ,  308   f  that emit light within the second range of wavelengths λ 1 -λ 2 . 
       FIG. 4  illustrates another system  400  for reading graphical codes in accordance with the present disclosure. The system  400  of  FIG. 4  is similar to the system  200  that was discussed above in connection with  FIG. 2 , except as indicated below. 
     In the depicted system  400 , the position of the illumination blocks  412  may be adjusted so that different supplemental light sources  408  are positioned at different angles with respect to the target area  424 . For example, the illumination blocks  412  may be adjusted so that some of the supplemental light sources  408   a ,  408   b ,  408   e ,  408   f  are positioned substantially perpendicular to a target area  424 , while other supplemental light sources  408   c ,  408   d ,  408   g ,  408   h  are positioned at an angle θ with respect to the target area  424 . 
     The ability to position the illumination blocks  412   a - d  so that different supplemental light sources  408  are positioned at different angles with respect to the target area  424  provides a user of the reader  402  with even greater flexibility. The user is able to easily experiment with the illumination blocks  412  in different positions until the direction of the illumination is optimized for the particular environment in which the reader  402  is being used. 
     It is to be understood that the claims are not limited to the precise configuration and components illustrated above. Various modifications, changes and variations may be made in the arrangement, operation and details of the systems, methods, and apparatus described herein without departing from the scope of the claims.