Abstract:
Systems and techniques for improved imaging scanning. An imaging bar code scanner provides indicia to a user indicating areas for placement of a bar code so as to provide for efficient imaging scanning. The indicia may define the boundaries of the field of view of an imager, and may also indicate areas of an image that are more intensively processed. The indicia may be projected so as to illuminate an object with a projected pattern, or may alternatively be projected onto or otherwise placed on one or more scan windows of a scanner. At least some of the indicia may change appearance depending on whether an object to be scanned is within a prescribed distance from an imager.

Description:
FIELD OF THE INVENTION  
       [0001]    The present invention relates generally to improvements to bar code scanning. More particularly, the invention relates to improved systems and techniques for indicating an optimum position for a bar code to be scanned by imaging scanning 
       BACKGROUND OF THE INVENTION  
       [0002]    Retail checkout operations, have used bar code scanning for many years, and bar code scanning has proven to be of great value in numerous other applications as well. Improved efficiency and accuracy of bar code scanning typically leads to improved efficiency of operations in which such scanning is used. One promising bar code scanning technology is imaging scanning, involving the capture and processing of a visual image of a bar code by an imaging device such as a digital camera, in order to extract bar code information. One important aspect of providing efficient imaging bar code scanning is the ability to quickly locate the bar code. The process of imaging scanning is essentially the analysis of a highly detailed photographic image. Filtering and manipulation of the image can help to simplify the processing, but analysis is typically a highly computationally intensive task. The initial capturing of the image typically does not distinguish the bar code from surrounding features of the image. That is, an image within a particular field of view is captured, and then processing is performed to identify and analyze the portion of the image representing the bar code. 
       SUMMARY OF THE INVENTION  
       [0003]    Among its several aspects, the present invention recognizes that control of the capturing of the image so as to reduce processing of captured extraneous material would be highly advantageous. If the position of the bar code in the field of view of an imager can be to some extent known, a processing algorithm can be designed to adapt processing to take into account the expectation that a bar code will be in a particular location, for example, performing more intensive processing in an expected location of a bar code and performing less intensive processing in what are expected to be background areas. 
         [0004]    In addition, a typical imaging scanner has an ideal distance from the imager at which the best processing occurs. Especially for very small bar codes, for which imaging scanning is particularly useful, it is highly desirable for the bar code to be placed an optimum distance from the imager in order for efficient scanning to occur. 
         [0005]    The present invention addresses these issues, as well as others, by providing for indicators for appropriate positioning of a bar code. A scanning field, such as a scan window, is provided with indicia indicating appropriate positioning in the field. For example, an illuminated grid, such as an intersecting horizontal and vertical line may be imposed on the window, for example, suitably channeled laser illumination, a projection onto the screen, or a design physically superimposed on the scan window. A design may be superimposed, for example, through painting, etching, or silk screen printing. In addition, a sensor may detect the distance of a bar code from the imager, and a targeting beam may be used to illuminate the bar code. When the sensor detects that the bar code is within a prescribed distance range from the imager, the appearance of the targeting beam may change. For example, the beam may change from red to green in color when the bar code is within the prescribed distance range. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0006]      FIG. 1  illustrates a checkout system employing a scanner according to an aspect of the present invention; 
           [0007]      FIG. 2  illustrates an additional view of a scanner according to an aspect of the present invention; 
           [0008]      FIGS. 3 and 4  illustrate scan windows suitably employed in a scanner according to an aspect of the present invention; 
           [0009]      FIG. 5  illustrates a handheld scanner according to an aspect of the present invention; and 
           [0010]      FIG. 6  illustrates a process of imaging scanning according to an aspect of the present invention. 
       
    
    
     DETAILED DESCRIPTION  
       [0011]      FIG. 1  illustrates a checkout system  100  according to an aspect of the present invention. The system  100  includes a point of sale terminal  102 , suitably including a computer  104 . The computer  104  may suitably include a processor  106 , high speed memory  108 , long term storage  110 , all communicating over a bus  112 . The terminal  102  may employ a user interface  114 , including a keyboard  116  and display screen  118 . The user interface  114 , as well as a payment interface  120 , and scanner/scale combination  122 , communicate with the computer  104  through one or more interface connections, such as the interface  124 . The interface  124  may suitably be a set of universal serial bus (USB) ports, a combination of USB ports and other types of ports, or any other combination of communication connectors or other connection mechanisms, such as wireless links suitable to the context and environment in which the system  100  is to be employed. The computer  104  may communicate with a central server  126  over a local area network  128 , which may include wired or wireless communication links, or both. 
         [0012]    The scanner  122  includes a base  130 , a tower section  134 , and horizontal and vertical scan windows  136  and  138 . The scanner  122  also includes imaging devices, such as digital cameras  140  and  142 , distance sensors  144  and  146 , target illuminators  148  and  150 , and a control and image processing system  152 . The control and image processing system.  152  may suitably include a processor  154 , memory  156 , and long term storage such as flash memory  158 . The scanner  122  includes a target grid projector  160 , suitably mounted in the tower section  134 , and oriented to project a targeting grid onto the horizontal window  136 . The scanner also includes a targeting grid illuminating system  162 , including a laser  164  and an optics system  166 , for directing a desired pattern onto the vertical window  138 . Numerous alternative mechanisms may be used for presenting a desired pattern on one or both of the windows  136  and  138 , such as painting or etching of pattern elements, or the use of electroluminescent wires embedded into a window. 
         [0013]    In many cases, it will be advantageous not only to place a bar code at or near a particular position with respect to a scan window, but to position the bar code within a specified distance range from the scan window, such as between 1 and 2 inches from the scan window, in order to place the bar code at or near an ideal focusing distance from the imager. A targeting beam, for example, the targeting beam  170 , may be emitted by a target illuminator, for example the target illuminator  148 . A bar code may be placed in the path of the targeting beam  170  by a user. 
         [0014]    The distance sensors  144  and  146  may suitably be infrared sensors, directing a beam past the windows  136  and  138 , respectively, and receiving reflections from objects in the path of the beams, or may be focus sensors, or any other type of sensor suited to use in the scanner  100 . When the distance to an object is determined by one of the sensors  144  and  146 , a signal indicating the distance is directed to the control and processing system  152 . When the determined distance is within a predetermined range, the control and processing system  152  directs the target illuminator  148  to change the appearance of the targeting beam  170 . For example, the targeting beam  170  may be changed so as to present a different shape, or may be changed in color, for example, from red to green. The user is thus informed when the bar code is at a proper distance from the scan window  138  and is therefore able to more quickly place the bar code at that proper distance. 
         [0015]    In addition to the scanner/scale combination  122 , the checkout station may also include a handheld scanner  180 . The handheld scanner  1   80  may be held near a bar code and activated so as to capture an image of the bar code area. As discussed further below, the handheld scanner  180  suitably projects a targeting pattern onto a countertop, or onto an object to be scanned, so that proper placement of a bar code with respect to the targeting pattern will produce efficient image scanning of the bar code. 
         [0016]      FIG. 2  illustrates an external view of the scanner  122 , removed from the checkout station  100 . The base  130 , tower section  132 , and horizontal and vertical scan windows  136  and  138  can be seen in  FIG. 2 . The targeting beam  170  can also be seen emerging from the scan window  138 . A targeting pattern  202  may be seen on the horizontal scan window  136 , comprising a border  204 , indicating the extent of the scan window  136  that is within the field of view of the digital camera  142 . The targeting pattern  202  includes horizontal and vertical lines  206  and  208 , and the intersection  210  of the lines  206  and  208  indicates a desired location for placement of a bar code for image scanning at the window  136 . Similarly, a targeting pattern  212  may be seen on the horizontal scan window  138 , comprising a border  214 , indicating the extent of the scan window  138  that is within the field of view of the digital camera  140 . The targeting pattern  212  includes horizontal and vertical lines  216  and  218 , and the intersection  220  of the lines  216  and  218  indicates a desired location for placement of a bar code for image scanning at the window  138 . The targeting beam  170  can be seen emerging from the scan window  138 , striking an object  222  held in position before the scan window  138 . When the object  222  is within a predetermined distance range from the scan window  138 , the targeting beam  170  will take on a predetermined appearance, for example, casting a predetermined pattern onto the object  222 , or taking on a green color, rather than, for example, a red color indicating that the object  222  is outside of the predetermined distance range. 
         [0017]      FIG. 3  illustrates additional features of a scan window such as the scan window  136 , showing the imaging area  202  of the imager  140 , the border  204 , and intersecting lines  206  and  208 . The bar code label  250 , bearing the bar code  252 , can be seen, as can the bar code label  260 , bearing the bar code label  262 . The bar code label  250  and bar code  252  are placed along the line  206 , and the bar code label  260  and label  262  are placed along the line  208 , which indicate favorable locations for imaging scanning. For example, more intensive processing may be performed at these portions of the imaging area, and the presence of the lines  206  and  208  indicates these favorable placement locations to a user. 
         [0018]      FIG. 4  illustrates a scan window such as the scan window  136 , showing the imaging area  202  of the imager  140 , again showing the border  204 , and intersecting lines  206  and  208 . The bar code label  290 , bearing the bar code  292  can be seen, as can the bar code label  294 , bearing the bar code label  296 . In addition, a series of lines  280 A. . . .  280 AA are used to illustrate processing density for the image, with a greater density of lines indicating more intensive processing in an area of the image and a lesser density of lines indicating less intensive processing in an area of the image. In the presently illustrated example, processing includes taking rows and columns of pixels from the image and subjecting them to processing. Rows and columns to be processed may be selected at intervals, to avoid the added processing load that would be required by processing every row of pixels. The lines  280 A. . . .  280 AA indicate the intervals at which processing of rows of pixels is performed, with a smaller interval being observed, and thus a greater intensity of processing being performed, nearer the horizontal line  206 . The bar code label  290  and bar code  292  are placed in an area in which the interval between lines is greater, and the bar code label  294  and bar code  296  are placed in an area for in which the interval between lines is less. The bar code  292  is relatively large, and so even with a larger interval between lines that are processed, sufficient lines of pixels including portions of the bar code  292  will be processed. The bar code  296  is relatively small, and placement of the bar code  296  in an area of the image for which more intensive processing is performed, that is in the area of the lines  280 H- 280 T where a smaller interval between lines is observed, provides a higher likelihood that the bar code  296  will be detected and processed. The lines  280 H- 280 T are arranged around the line  206 , showing a greater processing density in that area, and the line  206  provides an indication to a user of where a smaller bar code may advantageously be placed. 
         [0019]      FIG. 5  illustrates the use of the handheld scanner  180  according to an aspect of the present invention. The scanner  180  is illustrated here as being used to scan a bar code  502  affixed to a box  504 . The scanner  180  projects a targeting pattern  505  on the box  504 , showing a border  506  and intersecting vertical and horizontal lines  508  and  510 . The bar code  502  is shown here as having been placed on the horizontal line  508 , which may suitably have been used to indicate an area suitable for imaging scanning, such as an area of the field of view of an imager that is subjected to relatively intensive processing. Also visible is a targeting beam  512 , projecting a distance targeting spot  514 . The distance targeting spot  514  suitably changes in appearance, such as changing in color, depending on whether an object to be scanned is within a predetermined distance range from an imager used in a scanner such as the scanner  180 . 
         [0020]      FIG. 6  illustrates a process  600  of imaging checkout according to an aspect of the present invention. At step  602 , an imaging scanner is activated for scanning and an imager takes a view of an imaging area. At step  604 , a targeting beam is emitted for illumination of a bar code, to help indicate when the bar code is at a proper distance for imaging scanning, such as within a predetermined distance range from an imager at which scanning occurs more easily. At step  606 , when a bar code suitable for imaging scanning is to be scanned, the bar code is moved into a position for imaging scanning, with proper positioning being indicated by indicia visible to a user of the scanner. The indicia may indicate positions at which more intensive or less intensive processing of the imaging area occurs, in order to help a user to place a bar code more precisely in cases in which such placement is needed, such as when a smaller bar code is better placed in an area where more intensive processing occurs. The bar code is also suitably positioned so as to be illuminated by the targeting beam and moved so as to put it at an appropriate distance from the imager. At step  608 , when the bar code is detected to be at a desired distance from the imager, the targeting beam takes on an appearance indicating that the bar code is at a proper distance. At step  610 , an image of the imaging is captured. The captured image provided for processing thus shows the bar code at the desired position and distance. At step  612 , the area of the image including the bar code is located and processed and bar code information extracted. 
         [0021]    While the present invention is disclosed in the context of a presently preferred embodiment, it will be recognized that a wide variety of implementations may be employed by persons of ordinary skill in the art consistent with the above discussion and the claims which follow below.