Registers – Coded record sensors – Feed mechanisms
Reexamination Certificate
2002-07-12
2004-10-12
Lee, Diane I. (Department: 2876)
Registers
Coded record sensors
Feed mechanisms
C235S477000, C235S462120, C235S436000, C235S380000
Reexamination Certificate
active
06802452
ABSTRACT:
FIELD OF TEE INVENTION
The disclosed device relates to bar code scanners which are used to scan card resident bar codes for identification and other purposes in most industrialized countries. More particularly it relates to an improved method and apparatus for the faster and more accurate reading of linear and 2D bar codes which allows for progressive reading of the card when inserted into the reader thereby eliminating any aiming by the user as well as providing fast and accurate reading of the card which is read as it is pushed into the reader. The device uses a line by line approach to reading of the card as it moves laterally across the sensor. It also self aligns the card with the reading device, eliminates the need for the user to aim a reading device at the card, while concurrently alleviating the time delays caused by conventional image type readers as well as lowering power consumption and the size requirements of the card reader itself. The device also incorporates a unique method of reading such bar codes which provides for a second scan of the barcode during exit from the device wherein it will either scan the entire barcode, or scan the barcode and combine it with the first scan to find missing data from the first scan, only if needed, thereby speeding up the scanning of the bar code.
BACKGROUND OF THE INVENTION
Ever prevalent in the lives of people in most industrialized countries is the use of bar codes to identify products and memorialize other information. There are typically two types of bar codes in commercial use, a linear (1D) barcode and a two dimensional (2D) barcode. A conventional 1D bar code (one dimensional UPC bar code) is just a different way of encoding numbers and letters by using a combination of bars and spaces of varying widths which in essence is just another manner of entering data into a computer. A bar code generally does not contain descriptive data. It is a reference number that a computer uses to look up an associated record that contains descriptive data and other important information. For example, a barcode found on a soda can does not contain the product name, type of soda, or price, instead, it contains a 12-digit product number. When this number is scanned by the cashier at the check-out, it is transmitted to the computer which finds the record associated with that item number in the data base. The matching item record contains a description of the product, vendor name, price, quantity-on-hand, etc. The computer instantly does a “price lookup” and displays the price on the cash register. It also subtracts the quantity purchased from the quantity-on-hand. This entire transaction is done instantly. In a nutshell, a bar code typically has ID data encoded in it, and that data is used by computer to look up all specific information associated with the data.
Since computers cannot “read” bar codes, for a computer to make use of the information contained in the bar code, the bar code data must be captured and decoded into a data format that the computer can process. The device which reads or captures the bar code information and sends it to the decoder, is known as the bar code reader, generally called bar code scanner. A typical bar code reader kit consists of a scanner, decoder, and cable which interfaces the decoder to the computer. The Scanner scans the Bar Code symbol and captures the bars and spaces of the bar code and sends it to the decoder. The decoder translates the bars and spaces into corresponding electrical output and transmits that data to the computer in a traditional data format. A bar code scanner can either have the Decoder built into it, or have an interface between it and the computer.
The 2D barcode unlike linear codes can store the data within the code, therefore eliminating the needs for access to a database for getting the information. Large amounts of text and data can be stored securely and inexpensively. Some 2D bar codes are like a set of linear bar codes literally stacked on top of each other. Conventionally, the PDF417 is the best example of a stacked-bar symbol and is the most common of all 2D bar codes currently in use today. 2D bar codes also uses an advanced error correction instead of a check digits system. This error correction allows the symbol to withstand some physical damage without causing loss of data. This high level of error correction is far more advanced than conventional 1D linear bar codes with check digits.
Currently, four of the different types of bar code readers available include the pen type readers (bar code-wands), laser bar code scanners, CCD (Charge Couple Devices) barcode readers and camera-based barcode readers used for most two dimensional (2D) bar codes which contain much more information than standard vertical line bar codes. Each of these types uses a slightly different technology for reading and decoding a bar code.
Pen type barcode readers have a light source and a photo diode placed next to each other in the tip of a pen or wand. To read a bar code, a user drags the tip of the pen across all the bars, in a steady even motion. The photo diode measures the intensity of the light reflected back from the light source and generates a waveform corresponding to the widths of the bars and spaces in the bar code. The barcode reader sends the waveform to the decoder, which decodes the waveform and sends it to the computer in a traditional data format.
Laser barcode scanners work the same way as pen type barcode readers. The only main difference is that Laser barcode scanners use a laser beam as their light source, and typically employ either a reciprocating mirror or a rotating prism to scan the laser beam back and forth across the bar code. As with the pen type bar code reader, a photo diode is used to measure the intensity of the light reflected back from the bar code.
CCD barcode scanners use an array of tiny light sensors lined up in a row in the head of the barcode reader. Voltage waveform corresponding to the bars and spaces of the bar code is generated and sent to the decoder, which decodes the data and sends it to the computer. The main difference between a CCD barcode scanner, a pen type barcode scanner, and laser barcode scanner is that the CCD barcode scanner measures emitted ambient light from the bar code whereas pen or laser barcode scanners measure reflected light of a specific frequency originating from the scanner itself.
The camera-based barcode readers used for the majority of 2D bar codes which are becoming more popular due to increased data carrying ability, use a small video camera to capture an image of a bar code. The barcode reader then transmits that information to a computer and uses sophisticated digital image processing techniques to decode the bar code. Unfortunately this type of image processing of the entire 2D bar code is time consuming, requires the aiming of a camera to properly capture the image, consumes large amounts of computer processing and memory as well as requiring substantial electrical power to run the camera.
Linear bar codes are decoded along one axis or direction and generally encode data characters as parallel arrangements of alternating, multiple-width strips of lower reflectivity or “bars” separated by absences of such strips having higher reflectivity or “spaces.” Each unique pattern of bars and spaces within a predetermined width defines a particular data character. A given linear symbol encodes several data characters along its length as several groups of unique bar and space patterns.
Newer data collection symbologies have departed from the typical linear symbologies to create 2D stacked or area symbologies in order to increase the amount of information encoded within a given area. Stacked symbologies or “multi-row symbologies” employ several adjacent rows of multiple-width bars and spaces. “Area symbologies” or 2D matrix symbologies employ arrangements of regular polygonal data cells where the center-to-center distance of adjacent cells is uniform Reading stacked symbologies and 2D area technologies with scanning beam-type d
Bradley Scott
Kim Hak
Lebaschi Ali
Harms Donn K.
Lee Diane I.
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