Patent Application
20080296387
1. Field of the Invention
The present invention generally relates to an electro-optical reader for reading indicia and, more particularly, to a point-of-transaction workstation for reading not only one-dimensional indicia, such as bar code symbols, but also for reading one- or two-dimensional indicia by image capture, as well as capturing images of other two-dimensional targets, such as signatures, checks, credit cards, debit cards, drivers' licenses, and people.
2. Description of the Related Art
Flat bed laser readers, also known as horizontal slot scanners, have been used to electro-optically read one-dimensional bar code symbols, particularly of the Universal Product Code (UPC) type, at a point-of-transaction workstation in supermarkets, warehouse clubs, department stores, and other kinds of retailers for many years. As exemplified by U.S. Pat. No. 5,059,779; U.S. Pat. No. 5,124,539 and U.S. Pat. No. 5,200,599, a single, horizontal window is set flush with, and built into, a horizontal countertop of the workstation. Products to be purchased bear an identifying symbol and are typically slid across the horizontal window through which a multitude of scan lines is projected in a generally upwards direction. When at least one of the scan lines sweeps over a symbol associated with a product, the symbol is processed and read.
The multitude of scan lines is generated by a scan pattern generator which includes a laser for emitting a laser beam at a mirrored component mounted on a shaft for rotation by a motor about an axis. A plurality of stationary mirrors is arranged about the axis. As the mirrored component turns, the laser beam is successively reflected onto the stationary mirrors for reflection therefrom through the horizontal window as a scan pattern of the scan lines.
It is also known to provide a point-of-transaction workstation with a generally vertical window that faces an operator at the workstation. The generally vertical window is oriented generally perpendicularly to the horizontal window, or is slightly rearwardly inclined. The scan pattern generator within this dual window or bi-optic workstation also projects the multitude of scan lines in a generally outward direction through the vertical window toward the operator. The generator for the vertical window can be the same as or different from the generator for the horizontal window. The operator slides the products past either window from right to left, or from left to right, in a “swipe” mode. Alternatively, the operator merely presents the symbol on the product to the center of either window in a “presentation” mode. The choice depends on operator preference or on the layout of the workstation.
Sometimes, the vertical window is not built into the workstation as a permanent installation. Instead, a vertical slot scanner is configured as a portable reader which is placed on the countertop of an existing horizontal slot scanner.
Each product must be oriented by the operator with the symbol facing away from the operator and directly towards either window. Hence, the operator cannot see exactly where the symbol is during scanning. In typical “blind-aiming” usage, it is not uncommon for the operator to repeatedly swipe or present a single symbol several times before the symbol is successfully read, thereby slowing down transaction processing and reducing productivity.
The blind-aiming of the symbol is made more difficult because the position and orientation of the symbol are variable. The symbol may be located low or high, or right to left, on the product, or anywhere in between. The symbol may be oriented in a “picket fence” orientation in which the elongated parallel bars of the one-dimensional UPC symbol are vertical, or in a “ladder” orientation in which the symbol bars are horizontal, or at any orientation angle in between.
In such an environment, it is important that the scan lines located at, and projected from, either window provide a full coverage scan zone which extends down as close as possible to the countertop, and as high as possible above the countertop, and as wide as possible across the width of the countertop. The scan patterns projected into space in front of the windows grow rapidly in order to cover areas on products that are positioned not on the windows, but several inches therefrom. The scan zone must include scan lines oriented to read symbols positioned in any possible way across the entire volume of the scan zone.
As advantageous as these point-of-transaction workstations are in processing transactions involving products associated with one-dimensional symbols each having a row of bars and spaces spaced apart along one direction, the workstations cannot process two-dimensional symbols, such as Code 39 which introduced the concept of vertically stacking a plurality of rows of bar and space patterns in a single symbol. The structure of Code 49 is described in U.S. Pat. No. 4,794,239. Another two-dimensional code structure for increasing the amount of data that can be represented or stored on a given amount of surface area is known as PDF417 and is described in U.S. Pat. No. 5,304,786. Such two-dimensional symbols are generally read by electro-optical readers operative for projecting a laser beam as a raster of scan lines, each line extending in one direction over a respective row, and all the lines being spaced apart along a height of the two-dimensional symbol in a generally perpendicular direction.
Both one- and two-dimensional symbols can also be read by employing solid-state imagers. For example, an image sensor device may be employed which has a one- or two-dimensional array of cells or photosensors which correspond to image elements or pixels in a field of view of the device. Such an image sensor device may include a one- or two-dimensional charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) device and associated circuits for producing electronic signals corresponding to a one- or two-dimensional array of pixel information for a field of view.
It is therefore known to use a solid-state device for capturing a monochrome image of a symbol as, for example, disclosed in U.S. Pat. No. 5,703,349. It is also known to use a solid-state device with multiple buried channels for capturing a full color image of a target as, for example, disclosed in U.S. Pat. No. 4,613,895. It is common to provide a two-dimensional CCD with a 640×480 resolution commonly found in VGA monitors, although other resolution sizes are possible.
It is also known to install an imager, as embodied in a consumer digital camera, in a point-of-transaction workstation, as disclosed in U.S. Pat. No. 7,191,947. However, the imager and the laser scan pattern generator share one of the windows, that is, they both scan a portion of the same window. This results in redundant scanning and processing at that portion of the shared window, which is an inefficient use of processing resources. Also, by having one or more laser scan pattern generators in the workstation, the overall system is complex and relatively expensive.
One feature of this invention resides, briefly stated, in an arrangement for, and a method of, processing transactions, comprising a stationary point-of-transaction workstation having a plurality of windows or ports, and an electro-optical reader mounted within the workstation, the reader being operative for projecting a laser beam light as a plurality of scan lines exclusively through only one of the windows, and for electro-optically reading a one-dimensional indicium associated with a transaction presented at the one window when at least one of the scan lines is swept across at least a part of the one-dimensional indicium. By way of example, the one-dimensional indicium is a UPC symbol associated with an object passing through the workstation. In the preferred application, the object is a product to be purchased by a consumer, and the workstation is installed in a retail establishment, such as a supermarket.
A one- or two-dimensional, solid-state imager, preferably a charge coupled device (CCD) array, is also mounted at the workstation, and is operative for capturing light from a one- or two-dimensional target exclusively through another of the windows. In accordance with a feature of this invention, each window allows the light to pass therethrough to only one of the reader and the imager. Hence, the imager and the reader do not, as taught in the prior art, share one of the windows, and they do not both scan a portion of the same window. Redundant scanning and processing at a shared window is avoided, thereby utilizing processing resources more efficiently, and simplifying the overall system.
The target may be a two-dimensional symbol to be electro-optically read. The target may also be a personal check, a credit card, or a debit card presented by the consumer for payment of the products being purchased. The target may also be a signature of the consumer, or the consumer himself or herself. The target may also be a form of identification of the consumer, such as a driver's license, especially one on which a two-dimensional symbol is pre-printed, for validating one's identity and age. The target may even be the operator himself or herself for use in video surveillance for security purposes.
The imager is preferably associated with a high-speed illuminator to enable the image of the target to be acquired in a very short period of time, for example, on the order of 100 microseconds, so that the target image is not blurred even if there is relative motion between the imager and the target.
One of the windows is located in a horizontal plane, and one or more other windows, preferably recessed, lies in a generally upright plane that intersects the horizontal plane. A weighing scale may be mounted at the workstation, and one of the windows may be incorporated into the scale. A register may also be mounted at the workstation, and one of the windows may be incorporated into the register. Another solid-state imager is mounted in the register for capturing light from the target preferably located at the horizontal plane. If a solid-state imager is mounted below the horizontal plane, then room exists for a drawer to be mounted below the horizontal plane. In addition, a radio frequency identification (RFID) reader may be mounted at the workstation.
The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
A laser scan pattern generator 20 or electro-optical reader, shown schematically in
In use, an operator 24, such as a person working at a supermarket checkout counter, processes a product 26 bearing a UPC symbol 28 thereon, past the windows 12, 18 by swiping the product across a respective window in the abovementioned swipe mode, or by presenting the product at the respective window in the abovementioned presentation mode. If the symbol 28 is located on the bottom of the product, then one of the scan lines projected through the horizontal window 12 will traverse the symbol. If the symbol 28 is located on the side of the product, then the imager will capture light from the symbol through the upright window 16.
In accordance with one feature of this invention, each window 12, 16 allows the light to pass therethrough to only one of the reader 20 and the imager 30. Hence, the imager 30 and the reader 20 do not, as taught in the prior art, share one of the windows, and they do not both scan a portion of the same window. Redundant scanning and processing at a shared window is avoided, thereby utilizing processing resources more efficiently, and simplifying the overall system.
As shown in
In operation, the microprocessor 34 sends a command signal to the illuminator 32 to pulse the LEDs for a short time period of 100 microseconds or less, and energizes the imager 30 to collect light from a target only during said time period. By acquiring a target image during this brief time period, the image of the target is not blurred even in the presence of relative motion between the imager and the target.
There are several different types of targets which have particular utility for the enhancement of the operation of the workstation. The target may be a personal check, a credit card, or a debit card presented by a customer for payment of the products being purchased. The operator need only swipe or present these payment targets at the window 16 for image capture.
The target may also be a signature, a driver's license, or the consumer himself or herself. Capturing an image of the driver's license is particularly useful since many licenses are encoded with two-dimensional indicia bearing age information, which is useful in validating a customer's age and the customer's ability to purchase age-related products, such as alcoholic beverages or tobacco products.
The target may be the operator himself or herself, which is used for video surveillance for security purposes. Thus, it can be determined if the operator is actually scanning the products, or passing them around the window in an effort to bypass the window and not charge the customer in a criminal practice known in retailing as “sweethearting”.
The target may, of course, be two-dimensional symbols whose use is becoming more widespread, especially in manufacturing environments and in package delivery. Sometimes, the target includes various lengths of truncated symbols of the type frequently found on frequent shopper cards, coupons, loyalty cards, in which case the area imager can read these additional symbols.
The energization of the imager 30 can be manual and initiated by the operator. For example, the operator can depress a button, or a foot pedal, or simply open the drawer 50 of the workstation. The energization can also be automatic such that the imager operates in a continuous image acquisition mode which, of course, is the desired mode for video surveillance of the operator, as well as for decoding two-dimensional symbols.
The continuous video stream generated during a continuous image acquisition mode can, however, overload a conventional video processing circuit and, as a result, cause some frames of the target image to be dropped. A high-speed video processing circuit 36 receives the continuous video stream and, with the aid of an auto-discrimination circuit 38, determines and selects which images in the stream are one-dimensional symbols, which images are two-dimensional symbols, and which images are not symbols at all. The auto-discrimination circuit 38, after such selection, transfers only the symbols to the microprocessor 34 for decoding. The software to be downloaded to the auto-discrimination circuit is stored in the flash memory 44. This dramatically reduces the computational burden on the microprocessor 34. The non-symbol images can be directly transferred to a memory, such as RAM 40, or directly routed by the microprocessor to a host 42. The method used for autodiscrimination between one- and two-dimensional symbols is described in U.S. Pat. No. 6,250,551, the entire contents of which are incorporated herein by reference thereto.
It will be understood that each of the elements described above, or two or more together, also may find a useful application in other types of constructions differing from the types described above.
While the invention has been illustrated and described as embodied in a point-of transaction workstation for electro-optically reading one-dimensional indicia, including image capture of two-dimensional targets, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.
Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.
