An apparatus, method and system described herein relates generally to improvements to imaging bar code scanners. More particularly, the invention relates to improving the illuminating of a bar code or other optical code being scanned by the imaging bar code scanner.
Bar code scanners are used in a wide variety of applications that rely on bar codes to store information. Industries such as retail, airline, self service, automotive, parcel delivery, pharmaceutical, healthcare and others use bar codes to provide inventory control, customer identification, item tracking and many others functions. Bar code scanners scan or read a bar code that is typically attached to or printed on an object. A typical bar code is comprised of a number of bars separated by spaces. Information is encoded on a bar code by varying the width of the bars and spaces. When a bar code is placed within the field of view of a bar code scanner, the scanner will detect and analyze the bars and spaces comprising the bar code and then decode the information encoded in the bar code. This operation is also called scanning or reading a bar code. Information encoded on a bar code usually takes the form of an alphanumeric number.
An imaging bar code scanner reads a bar code by capturing a digital image of the bar code and then processing the image to detect and read the bar code. It is very important that the bar code scanner successfully read the bar code on the first pass of the bar code by the scanner. A good first pass read of a bar code helps to maintain workflow and speeds up the checkout process. It also reduces stress on the person operating the scanner. This is particularly true if the operator is a customer operating a self-checkout terminal.
Unfortunately, the location of illumination devices used to illuminate a bar code in imaging bar code scanners can hinder the scanners ability to achieve a high first pass read rate. The illumination devices are typically positioned near the optical axis of the image scanner, which causes light to be projected nearly parallel to the optical axis. (The optical axis is the path used by the image capture device to view and capture an image of the bar code.) This geometry does not work well when the bar code label has a reflective or glossy finish. The glossy finish on the bar code generates a large amount of specular reflections that obscures all or parts of the bar code. When the specular reflections are directed toward the image capture device of the imaging scanner, it is difficult or in some cases impossible to read the bar code. What is needed is a way to reduce or eliminate specular reflections directed to an image capture device of an imaging bar code scanner.
In the following description, numerous details are set forth to provide an understanding of the claimed invention. However, it will be understood by those skilled in the art that the claimed invention may be practiced without these details and that numerous variations or modifications from the described embodiments are possible.
Referring now to
The image scanner 115 includes one or more image illumination devices 120 that illuminate the bar code 150 and an image capture device 125 that captures an electronic image of the illuminated bar code 150. The image scanner 115 is further comprised of a processing module 135, interface hardware 140, and communications hardware 130. The processing module 135 comprises at least one processor, memory, stored instructions and hardware to control and interface with the other devices and modules of the image scanner 115. The processing module 135, by executing the stored instructions, controls the hardware devices and modules that comprise the image scanner 115 or are connected to the image scanner 115. In addition, the stored instructions cause the processor to: process images that have been captured by the image capture device 125 to read a bar code, control the communications hardware 130 to implement protocols used on the data network 165 and implement other software features and functions of the image scanner 115. In some cases, the store server 160 sends the image scanner 115 updates to the stored instructions or to the operating parameters of the image scanner 115.
The optimal orientation of the bar code 150 for being read by the imaging scanner 115 occurs when the bar code 150 is facing the optical axis 230 and aligned perpendicular to the optical axis 230 as shown in
This embodiment describes illumination devices 120 that are located on the right and left sides of the horizontal and vertical scanning windows (210 & 215). In some embodiments, the illumination devices 120 are located at the top and bottom of the scanning windows and in still other embodiments, the illumination devices 120 are located on all sides of each scanning window. In some embodiments, one or more illumination devices 120 are located inside the image scanner 115. Devices such as mirrors and/or light pipes are used to direct light generated by the one or more illumination devices 120 to the proper location on the image scanner 115 so that the light emerges from the image scanner 115 sufficiently removed from the optical axis. The mirrors or light pipes are also arranged direct the path of the light to an area where the bar code 150 passes by the image scanner 115.
In some embodiments, the image scanner 115 can to turn the illumination devices 120 on and off under program control. The processing module 135 controls each illumination device 120 and can turn each device off or on. When in a power saving mode, the processor turns off one or more of the illumination devices.
In some embodiments, the image scanner 115 is designed to read additional types of optical codes than just a bar code. These optical codes include text, numbers and symbols.
While the invention is disclosed in the context of an image bar code scanning embodiment, it will be recognized that a wide variety of implementations may be employed by a person of ordinary skill in the art consistent with the above discussion and the claims, which follow below.