Abstract:
A method and apparatus for intelligently controlling illumination patterns projected from barcode readers. The method includes (1) detecting a location of an object of interest with a plurality of object sensors each having a corresponding object field of view; and (2) selecting at least one illumination light source to project one or more illumination patterns in one or more predetermined directions at least based upon the location of the object determined with the plurality of object sensors.

Description:
FIELD OF THE DISCLOSURE 
       [0001]    The present invention relates to imaging-based barcode readers. 
       BACKGROUND 
       [0002]    Various electro-optical systems have been developed for reading optical indicia, such as bar codes. A bar code is a coded pattern of graphical indicia comprised of a series of bars and spaces of varying widths, the bars and spaces having differing light reflecting characteristics. The pattern of the bars and spaces encode information. Bar code may be one dimensional (e.g., UPC bar code) or two dimensional (e.g., DataMatrix bar code). Systems that read, that is, image and decode bar codes employing imaging camera systems are typically referred to as imaging-based bar code readers or bar code scanners. 
         [0003]    Imaging-based bar code readers may be portable or stationary. A portable bar code reader is one that is adapted to be held in a user&#39;s hand and moved with respect to a target indicia, such as a target bar code, to be read, that is, imaged and decoded. Stationary bar code readers are mounted in a fixed position, for example, relative to a point-of-sales counter. Target objects, e.g., a product package that includes a target bar code, are moved or swiped past one of the one or more transparent windows and thereby pass within a field of view of the stationary bar code readers. The bar code reader typically provides an audible and/or visual signal to indicate the target bar code has been successfully imaged and decoded. Sometimes barcodes are presented, as opposed to be swiped. This typically happens when the swiped barcode failed to scan, so the operator tries a second time to scan it. Alternately, presentation is done by inexperience users, such as when the reader is installed in a self check out installation. 
         [0004]    A typical example where a stationary imaging-based bar code reader would be utilized includes a point of sale counter/cash register where customers pay for their purchases. The reader is typically enclosed in a housing that is installed in the counter and normally includes a vertically oriented transparent window and/or a horizontally oriented transparent window, either of which may be used for reading the target bar code affixed to the target object, i.e., the product or product packaging for the product having the target bar code imprinted or affixed to it. The sales person (or customer in the case of self-service check out) sequentially presents each target object&#39;s bar code either to the vertically oriented window or the horizontally oriented window, whichever is more convenient given the specific size and shape of the target object and the position of the bar code on the target object. 
         [0005]    A stationary imaging-based bar code reader that has a plurality of imaging cameras can be referred to as a multi-camera imaging-based scanner or bar code reader. In a multi-camera imaging reader, each imaging camera is operative to capture an image from a predetermined field of view. The multi-camera imaging reader generally also includes one or more illumination light sources operative to project illumination patterns in a plurality of predetermined directions. The light intensities of these illumination patterns can be very bright. In certain circumstances, people positioned near the multi-camera imaging reader can be exposed to such bright light. Some people may consider the bright light annoying and bothersome. Some people may perceive the bright light as dangerous. Accordingly, it is desirable to find an intelligent method to minimize user exposures to the bright light projected from the multi-camera imaging reader. 
       SUMMARY 
       [0006]    In one aspect, an apparatus includes a housing, an imaging system, an illumination system, a plurality of object sensors, and electronic circuitry for selectively turning on one or more of the illumination patterns. The housing includes one or more transparent windows and defines a housing interior region. The imaging system includes one or more solid-state imagers, located within the housing interior region, operative to capture light from a plurality of predetermined fields of view. The illumination system includes a plurality of illumination light sources operative to project illumination patterns in a plurality of predetermined directions. Each object sensor is operative to detect the presence of the object within a corresponding object field of view, and the plurality of object sensors is operative to detect a location of an object. The electronic circuitry is operative to turn on one or more of the illumination patterns in one or more predetermined directions at least based upon the location of the object obtained with the plurality of object sensors. 
         [0007]    In another aspect, a method includes (1) detecting a location of an object with a plurality of object sensors each having a corresponding object field of view; (2) selecting at least one illumination light source to project one or more illumination patterns in one or more predetermined directions at least based upon the location of the object obtained with the plurality of object sensors; (3) capturing light reflected from a barcode on the object with an imaging system that includes one or more solid-state imagers located within an interior region of a housing having one or more transparent windows; and (4) processing an image captured by at least one of the solid-state imagers in the imaging system. 
         [0008]    Implementations of the invention can include one or more of the following advantages. The chances of exposing people near the workstation to the bright light projected from the workstation can be reduced. People are less likely to be offended by the bright light projected from the workstation. These and other advantages of the present invention will become apparent to those skilled in the art upon a reading of the following specification of the invention and a study of the several figures of the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0009]    The accompanying figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views, together with the detailed description below, are incorporated in and form part of the specification, and serve to further illustrate embodiments of concepts that include the claimed invention, and explain various principles and advantages of those embodiments. 
           [0010]      FIG. 1  depicts a workstation in accordance with some embodiments. 
           [0011]      FIG. 2  is a schematic of a bi-optical workstation that includes a plurality of solid-state imagers in accordance with some embodiments. 
           [0012]      FIGS. 3A-3D  are schematics of a bi-optical workstation that has four solid-state imagers in accordance with some embodiments. 
           [0013]      FIG. 4A  shows a group of other optical components associated the solid-state imager C 1  in  FIG. 3A  in accordance with some embodiments. 
           [0014]      FIGS. 5A-5D  depict a plurality of illumination patterns with the solid-state imagers in accordance with some embodiments. 
           [0015]      FIG. 6  shows that the illumination patterns are projected out of the workstation simultaneously in multiple predetermined directions in accordance with some embodiments. 
           [0016]      FIG. 7  depicts a workstation that includes two object sensors S 1  and S 2  in accordance with some embodiments. 
           [0017]      FIGS. 8A-8B  and  9 A- 9 B illustrate that the object sensors S 1  and S 2  can be used to measure the location of an object and such location can be used by the workstation to selectively turn on one or more of the illumination patterns in one or more predetermined directions. 
       
    
    
       [0018]    Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention. 
         [0019]    The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. 
       DETAILED DESCRIPTION 
       [0020]      FIG. 1  depicts a workstation  10  in accordance with some embodiments. The workstation  10  is stationary and includes a housing  20 . The housing  20  has a generally horizontal window  25 H and a generally vertical window  25 V. In one implementing, the housing  20  can be integrated into the sales counter of a point-of-transaction system. The point-of-transaction system can also includes a cash register, a touch screen visual display, a printer for generating sales receipts, or other type user interface. The workstation  10  can be used by retailers to process transactions involving the purchase of products bearing an identifying target, such as UPC symbols. 
         [0021]    In accordance with one use, either a sales person or a customer will present a product or target object  40  selected for purchase to the housing  20 . More particularly, a target bar code  30  imprinted or affixed to the target object will be presented in a region near the windows  25 H and  25 V for reading, that is, imaging and decoding of the coded indicia of the target bar code. Upon a successful reading of the target bar code, a visual and/or audible signal will be generated by the workstation  10  to indicate to the user that the target bar code  30  has been successfully imaged and decoded. 
         [0022]    As schematically shown in  FIG. 2 , a plurality of solid-state imagers  50 , each including an illuminator  52 , are mounted at the workstation  10 , for capturing light passing through either or both windows from a target which can be a one- or two-dimensional symbol, such as a two-dimensional symbol on a driver&#39;s license, or any document, as described below. Each imager  50  is a solid-state area array, preferably a CCD or CMOS array. The imagers  50  and their associated illuminators  52  are operatively connected to a programmed microprocessor or controller  54  operative for controlling the operation of these and other components. Preferably, the microprocessor is the same as the one used for decoding the return light scattered from the target and for processing the captured target images. 
         [0023]    In operation, the microprocessor  54  sends successive command signals to the illuminators  52  to pulse the LEDs for a short time period of 100 microseconds or less, and successively energizes the imagers  50  to collect light from a target only during said time period, also known as the exposure time period. By acquiring a target image during this brief time period, the image of the target is not excessively blurred. 
         [0024]    As previously stated,  FIG. 2  is only a schematic representation of an all imager-based workstation as embodied in a bi-optical workstation with two windows. The workstation can have other kinds of housings with different shapes. The workstation can have one window, two windows, or with more than two windows. In some embodiments, the workstation can include between three to six solid-state imagers. The bi-optical workstation can also include more than six solid-state imagers. 
         [0025]      FIGS. 3A-3D  are schematics of a bi-optical workstation that has four solid-state imagers in accordance with some embodiments. In  FIGS. 3A-3D , the bi-optical workstation includes four solid-state imagers C 1 , C 2 , C 3 , and C 4  commonly mounted on a printed circuit board  22 . The printed circuit board  22  lies in a generally horizontal plane generally parallel to, and below, the generally horizontal window  25 H.  FIGS. 5A-5D  depict a first illumination pattern  210 , a second illumination pattern  220 , a third illumination pattern  230 , and a fourth illumination pattern  240  that are respectively associated with solid-state imagers C 1 , C 2 , C 3 , and C 4 . 
         [0026]    As shown in  FIG. 3A , the solid-state imager C 1  faces generally vertically upward toward an inclined folding mirror M 1 - a  directly overhead at the left side of the horizontal window  25 H. The folding mirror M 1 - a  faces another inclined narrow folding mirror M 1 - b  located at the right side of the horizontal window  25 H. The folding mirror M 1 - b  faces still another inclined wide folding mirror M 1 - c  adjacent the mirror M 1 - a . The folding mirror M 1 - c  faces out through the generally horizontal window  25 H toward the right side of the workstation. 
         [0027]    In  FIG. 3A , it is shown that the solid-state imager C 1  is also associated with a group of other optical components  80 .  FIG. 4A  shows the group of other optical components  80  in details. In  FIG. 4A , it is shown that the solid-state imager C 1  includes a sensor array  81  and an imaging lens  82 . It is also shown that two light emitting diodes  85   a  and  85   b , spaced apart, are installed closely adjacent to the sensor array  81 . When the light emitting diode  85   a  (or  85   b ) is energized, light emitted from the light emitting diode  85   a  (or  85   b ) passes through a light pipe  86   a  (or  86   b ) and a lens  87   a  (or  87   b ). As shown in  FIG. 3A , light emitted from the light emitting diode  85   a  (or  85   b ), after bouncing off the folding mirrors M 1 - a , M 1 - b , and M 1 - c  sequentially, exits the housing  20  as the first illumination pattern  210  centered by the light ray  110 .  FIG. 5A  shows that the first illumination pattern  210  centered by the light ray  110  exits the housing  20  in a first predetermined direction. 
         [0028]    In  FIG. 3A , the folding mirrors M 1 - a , M 1 - b , and M 1 - c  also constitute part of an optical system for defining a predetermined field of view for the solid-state imager C 1 . Similar to the first illumination pattern  210  in  FIG. 5A , the predetermined field of view for the solid-state imager C 1  generally is also centered by the light ray  110 . In addition, the predetermined field of view for the solid-state imager C 1  is preferably within the first illumination pattern  210  as shown in  FIG. 5A . 
         [0029]      FIG. 3B  and  FIG. 5B  depict respectively the optical path for the solid-state imager C 2  and the second illumination pattern  220  associated with the solid-state imager C 2 . The solid-state imager C 2  and its associated optics in  FIG. 3B  is mirror symmetrical to the solid-state imager C 1  and its associated optics in  FIG. 3A . As shown in  FIG. 3B , the solid-state imager C 2  faces generally vertically upward toward an inclined folding mirror M 2 - a  directly overhead at the right side of the horizontal window  25 H. The folding mirror M 2 - a  faces another inclined narrow folding mirror M 2 - b  located at the left side of the horizontal window  25 H. The folding mirror M 2 - b  faces still another inclined wide folding mirror M 2 - c  adjacent the mirror M 2 - a . The folding mirror M 2 - c  faces out through the generally horizontal window  25 H toward the left side of the workstation. 
         [0030]    In  FIG. 3B , when a light emitting diode associated with solid-state imager C 2  is energized, light emitted from such light emitting diode, after bouncing off the folding mirrors M 2 - a , M 2 - b , and M 2 - c  sequentially, exits the housing  20  as the second illumination pattern  220  centered by the light ray  120 .  FIG. 5B  shows that the second illumination pattern  220  centered by the light ray  120  exits the housing  20  in a second predetermined direction. 
         [0031]      FIG. 3C  and  FIG. 5C  depict respectively the optical path for the solid-state imager C 3  and the third illumination pattern  230  associated with the solid-state imager C 3 . In  FIG. 3C , the solid-state imager C 3  faces generally vertically upward toward an inclined folding mirror M 3 - a  directly overhead at the left side of the vertical window  25 V. The folding mirror M 3 - a  faces another inclined narrow folding mirror M 3 - b  located at the right side of the vertical window  25 V. The folding mirror M 3 - b  faces still another inclined wide folding mirror M 3 - c  adjacent the mirror M 3 - a . The folding mirror M 3 - c  faces out through the generally vertical window  25 V toward the right side of the workstation. 
         [0032]    In  FIG. 3C , when a light emitting diode associated with solid-state imager C 3  is energized, light emitted from such light emitting diode, after bouncing off the folding mirrors M 3 - a , M 3 - b , and M 3 - c  sequentially, exits the housing  20  as the third illumination pattern  230  centered by the light ray  130 .  FIG. 5C  shows that the third illumination pattern  230  centered by the light ray  130  exits the housing  20  in a third predetermined direction. 
         [0033]      FIG. 3D  and  FIG. 5D  depict respectively the optical path for the solid-state imager C 4  and the fourth illumination pattern  240  associated with the solid-state imager C 4 . The solid-state imager C 4  and its associated optics in  FIG. 3D  is mirror symmetrical to the solid-state imager C 3  and its associated optics in  FIG. 3C . In  FIG. 3D , the solid-state imager C 4  faces generally vertically upward toward an inclined folding mirror M 4 - a  directly overhead at the right side of the vertical window  25 V. The folding mirror M 4 - a  faces another inclined narrow folding mirror M 4 - b  located at the left side of the vertical window  25 V. The folding mirror M 4 - b  faces still another inclined wide folding mirror M 4 - c  adjacent the mirror M 4 - a . The folding mirror M 4 - c  faces out through the generally vertical window  25 V toward the left side of the workstation. 
         [0034]    In  FIG. 3D , when a light emitting diode associated with solid-state imager C 4  is energized, light emitted from such light emitting diode, after bouncing off the folding mirrors M 4 - a , M 4 - b , and M 4 - c  sequentially, exits the housing  20  as the fourth illumination pattern  240  centered by the light ray  140 .  FIG. 5D  shows that the fourth illumination pattern  240  centered by the light ray  140  exits the housing  20  in a forth predetermined direction. 
         [0035]    In some of the existing designs of the workstation, as shown in  FIG. 6 , the illumination patterns  210 ,  220 ,  230 , and  240  are projected out of the workstation simultaneously or in rapid sequence in multiple predetermined directions. The light intensities of these illumination patterns can be very bright. A person located in front of the horizontal window or the vertical windows can be exposed to such bright light if looked directly towards these windows. For example, when a casher sits in front of a full-service workstation or when a short person (e.g., a child) stands at a self-checkout workstation, this person may subject his/her eyes to direct exposure of the bright light, because his/her face may be located at the same level as the scanner vertical window. Specifically, as shown in  FIG. 6 , face F 3  can be exposed to the bright light of the third illumination pattern  230  and face F 4  can be exposed to the bright light of the fourth illumination pattern  240 . The person exposed to the bright light may consider such light annoying and bothersome. Some people may perceive the bright light as dangerous even the bright light is reasonably safe and it has satisfied the requirement of all relevant regulatory codes. It is desirable to find an intelligent method to minimize user exposures to the bright light projected from the workstation. One implementation of such intelligent method is illustrated in  FIGS. 7 ,  8 A- 8 B, and  9 A- 9 B. 
         [0036]      FIG. 7  depicts a workstation that includes two object sensors S 1  and S 2 . Each object sensor is associated with a corresponding object field of view. Each object sensor is operative to detect the presence of an object within the corresponding field of view of the object sensor. As shown in  FIG. 7 , the object sensor S 1  is associated with a object field of view  310 , and the object sensor S 2  is associated with a object field of view  320 . 
         [0037]      FIGS. 8A and 9A  illustrate that the object sensors S 1  and S 2  can be used to determine the location of an object  40 .  FIGS. 8B and 9B  illustrates that the obtained location of the object of interest can be used by the workstation to selectively turn on one or more of the illumination patterns in one or more predetermined directions. 
         [0038]    At a first instant, as shown in  FIG. 8A , when the object  40  is moved across the workstation, it may enter the object field of view  320  of the object sensor S 2  before entering the object field of view  310  of the object sensor S 1 . When the workstation recognizes that the object  40  is in the object field of view  320  but this object has not reached the object field of view  310 , the workstation can selectively turn on the third illumination pattern  230 , as shown in  FIG. 8B . In this specific implementation, if only the third illumination pattern  230  is turned on, the risk of exposing the users to the bright light of the illumination patterns may be reduced. As shown in  FIG. 8B , the face F 4  at the left side of the workstation receives no bright light, because the fourth illumination pattern  240  is not turned on. The face F 3  at the right side of the workstation receives little or no bright light, because light from the third illumination pattern  230  is substantially blocked by the object  40 . 
         [0039]    At a first instant, as shown in  FIG. 9A , when the object  40  is moved across the workstation, it may enter the object field of view  310  of the object sensor S 1  after leaving the object field of view  320  of the object sensor S 2 . When the workstation recognizes that the object  40  in the object field of view  310  but this object has left the object field of view  320 , the workstation can selectively turn on the fourth illumination pattern  240 , as shown in  FIG. 9B . In this specific implementation, if only the fourth illumination pattern  240  is turned on, the risk of exposing the users to the bright light of the illumination patterns may be reduced. As shown in  FIG. 9B , the face F 3  at the right side of the workstation receives no bright light, because the third illumination pattern  230  is not turned on. The face F 4  at the left side of the workstation receives little or no bright light, because light from the fourth illumination pattern  240  is substantially blocked by the object  40 . 
         [0040]    In the implementation as shown in  FIGS. 8A-8B , when the object  40  is in the object field of view  320 , only the third illumination pattern  230  is turned on. In other implementations, when the object  40  is in the object field of view  320 , both the first illumination pattern  210  and the third illumination pattern  230  can be turned on. In these implementations, both the light emitting diodes associated with solid-state imager C 1  in  FIG. 3A  and the light emitting diodes associated with solid-state imager C 3  in  FIG. 3C  can be turned on. 
         [0041]    In the implementation as shown in  FIGS. 9A-9B , when the object  40  is in the object field of view  310 , only the fourth illumination pattern  240  is turned on. In other implementations, when the object  40  is in the object field of view  310 , both the second illumination pattern  220  and the fourth illumination pattern  240  can be turned on. In these implementations, both the light emitting diodes associated with solid-state imager C 2  in  FIG. 3B  and the light emitting diodes associated with solid-state imager C 4  in  FIG. 3D  can be turned on. 
         [0042]    In the implementation as shown in  FIG. 7 , the workstation includes two object sensors S 1  and S 2 . In other implementations, the workstation can include three or more object sensors. For example, the workstation in  FIG. 10  includes object sensors S 1 , S 2 , and S 3 . Each object sensor is operative to detect the presence of an object within the field of view of the object sensor. As shown in  FIG. 10 , the object sensor S 1  is associated with a object field of view  310 , the object sensor S 2  is associated with a object field of view  320 , and the object sensor S 3  is associated with a object field of view  330 . 
         [0043]    In the implementation as shown in  FIGS. 3A-3D , the workstation includes four solid-state imagers, and each solid-state imager has a field of view associated with an illumination pattern. In other implementations, the workstation can have six or more fields of views, and each field of view can be associated with a corresponding illumination pattern. In addition, when the workstation includes three or more object sensors, not only the location information but also other information about the object can be obtained from these object sensors. With more object sensors specially designed and distributed on the workstation, the workstation can make more intelligent decisions on which of the multiple illumination patterns should be turned on at any given time. 
         [0044]    In the foregoing specification, specific embodiments have been described. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of present teachings. 
         [0045]    The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential features or elements of any or all the claims. The invention is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued. 
         [0046]    Moreover in this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” “has”, “having,” “includes”, “including,” “contains”, “containing” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises, has, includes, contains a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by “comprises . . . a”, “has . . . a”, “includes . . . a”, “contains . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises, has, includes, contains the element. The terms “a” and “an” are defined as one or more unless explicitly stated otherwise herein. The terms “substantially”, “essentially”, “approximately”, “about” or any other version thereof, are defined as being close to as understood by one of ordinary skill in the art, and in one non-limiting embodiment the term is defined to be within 10%, in another embodiment within 5%, in another embodiment within 1% and in another embodiment within 0.5%. The term “coupled” as used herein is defined as connected, although not necessarily directly and not necessarily mechanically. A device or structure that is “configured” in a certain way is configured in at least that way, but may also be configured in ways that are not listed. 
         [0047]    It will be appreciated that some embodiments may be comprised of one or more generic or specialized processors (or “processing devices”) such as microprocessors, digital signal processors, customized processors and field programmable gate arrays (FPGAs) and unique stored program instructions (including both software and firmware) that control the one or more processors to implement, in conjunction with certain non-processor circuits, some, most, or all of the functions of the method and/or apparatus described herein. Alternatively, some or all functions could be implemented by a state machine that has no stored program instructions, or in one or more application specific integrated circuits (ASICs), in which each function or some combinations of certain of the functions are implemented as custom logic. Of course, a combination of the two approaches could be used. 
         [0048]    Moreover, an embodiment can be implemented as a computer-readable storage medium having computer readable code stored thereon for programming a computer (e.g., comprising a processor) to perform a method as described and claimed herein. Examples of such computer-readable storage mediums include, but are not limited to, a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a ROM (Read Only Memory), a PROM (Programmable Read Only Memory), an EPROM (Erasable Programmable Read Only Memory), an EEPROM (Electrically Erasable Programmable Read Only Memory) and a Flash memory. Further, it is expected that one of ordinary skill, notwithstanding possibly significant effort and many design choices motivated by, for example, available time, current technology, and economic considerations, when guided by the concepts and principles disclosed herein will be readily capable of generating such software instructions and programs and ICs with minimal experimentation. 
         [0049]    The Abstract of the Disclosure is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in various embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.