Types of barcode readers
Wednesday, December 2, 2009
• Pen type readers
Pen type readers consist of a light source and photodiodes, which are located side by side on the tip of a pen or wand. If you want to read the bar code, the tip of the pen moves across the bars in constant motion. Photodiode measuring intensity of light reflected from the light source and creates a wave that is used to measure the width of bars and spaces in the barcode. Dark bars in the bar code absorb light and white spaces reflect light so that the wave of tension created by photo diode is a representation of the structure of space bar and bar code. This course is decoded by the scanner in a similar way as the way Morse code dots and stripes are decoded.
• Laser Scanner
Laser scanners work the same way as pen type readers except that using a laser as a light source and typically use either an alternative or a rotating mirror prism scanning laser beam back and forth across the bar code. As with the pen type reader, photodiodes used to measure the intensity of light reflected in the barcode. In both pen readers, laser scanners, light emitted by the reader meets a certain frequency and a photodiode is designed to detect only this modulated light at the same frequency.
• CCD Readers
CCD readers (also known as LED scanner) uses a variety of hundreds of tiny light sensors lined up behind him after the reader. Each sensor measures the intensity of light immediately before him. Each individual light sensor in the CCD reader is extremely small and therefore, there are hundreds of sensors lined up in a row, the voltage pattern identical to the model of the bar code is generated in the reader gradually through the measurement of voltage, each sensor "line. The main difference between the CCD reader and a pen or laser scanner is that the CCD reader is measuring ambient light emission bar code whereas pen or laser scanners are measuring reflected light of specific frequencies from the scanner itself.
• The camera Readers
2D imaging scanners are the fourth and last type of bar code readers currently available. They use a small video camera to capture images of bar code. Then, the reader uses sophisticated digital image processing techniques for decoding bar codes. Video cameras use CCD technology in CCD bar code reader except that instead of one set of sensors, video camera has hundreds of sensors arranged in a series of two-dimensional array so that they can create an image.
There are several open source libraries to read barcode images. These include ZXing project, which is one-and two-dimensional bar codes use the Android operating system and Java JJIL project that contains code for reading bar code EAN-13 camera phone using J2ME, Zebra (ZBAR name change?), Which reads some two -dimensional bar codes VCI integration site, and either reads the image (eg, Folke Ashberg: EAN-13-scan imaging tools and code creation), or with connectors (eg Barcodepedia uses Flash and a Web Cam to see database applications), which options are taken to address the challenges.
• Omni-Directional Barcode Scanners
Omni-directional scanning using "a number of lines or curves to examine the different addresses in the form of bursting, Lissajous figure, or other device, the angles are a symbol and one or more of them will be able through all bars and spaces of the symbol, regardless of orientation."
Omni-directional Almost all laser scanners. Unlike simple single-line laser scanners, which produce a model beams from different directions, which can read bar codes, which are presented at different angles. Most of them use a single rotating polygon mirror and a few of the fixed mirror to generate intricate patterns of their survey.
Omni-directional scanners are more familiar means of horizontal sensors in supermarkets, where the package slipped through the glass or sapphire glass. There are a wide variety of omni-directional units available, which can be used for various test applications, from commercial applications to read barcode scanner a few inches from the industrial belt, where the drive scan can be several meters or more from your code.
Omni-directional scanners are also better at reading poorly printed bar codes or wrinkled Ripped.
Pen type readers consist of a light source and photodiodes, which are located side by side on the tip of a pen or wand. If you want to read the bar code, the tip of the pen moves across the bars in constant motion. Photodiode measuring intensity of light reflected from the light source and creates a wave that is used to measure the width of bars and spaces in the barcode. Dark bars in the bar code absorb light and white spaces reflect light so that the wave of tension created by photo diode is a representation of the structure of space bar and bar code. This course is decoded by the scanner in a similar way as the way Morse code dots and stripes are decoded.
• Laser Scanner
Laser scanners work the same way as pen type readers except that using a laser as a light source and typically use either an alternative or a rotating mirror prism scanning laser beam back and forth across the bar code. As with the pen type reader, photodiodes used to measure the intensity of light reflected in the barcode. In both pen readers, laser scanners, light emitted by the reader meets a certain frequency and a photodiode is designed to detect only this modulated light at the same frequency.
• CCD Readers
CCD readers (also known as LED scanner) uses a variety of hundreds of tiny light sensors lined up behind him after the reader. Each sensor measures the intensity of light immediately before him. Each individual light sensor in the CCD reader is extremely small and therefore, there are hundreds of sensors lined up in a row, the voltage pattern identical to the model of the bar code is generated in the reader gradually through the measurement of voltage, each sensor "line. The main difference between the CCD reader and a pen or laser scanner is that the CCD reader is measuring ambient light emission bar code whereas pen or laser scanners are measuring reflected light of specific frequencies from the scanner itself.
• The camera Readers
2D imaging scanners are the fourth and last type of bar code readers currently available. They use a small video camera to capture images of bar code. Then, the reader uses sophisticated digital image processing techniques for decoding bar codes. Video cameras use CCD technology in CCD bar code reader except that instead of one set of sensors, video camera has hundreds of sensors arranged in a series of two-dimensional array so that they can create an image.
There are several open source libraries to read barcode images. These include ZXing project, which is one-and two-dimensional bar codes use the Android operating system and Java JJIL project that contains code for reading bar code EAN-13 camera phone using J2ME, Zebra (ZBAR name change?), Which reads some two -dimensional bar codes VCI integration site, and either reads the image (eg, Folke Ashberg: EAN-13-scan imaging tools and code creation), or with connectors (eg Barcodepedia uses Flash and a Web Cam to see database applications), which options are taken to address the challenges.
• Omni-Directional Barcode Scanners
Omni-directional scanning using "a number of lines or curves to examine the different addresses in the form of bursting, Lissajous figure, or other device, the angles are a symbol and one or more of them will be able through all bars and spaces of the symbol, regardless of orientation."
Omni-directional Almost all laser scanners. Unlike simple single-line laser scanners, which produce a model beams from different directions, which can read bar codes, which are presented at different angles. Most of them use a single rotating polygon mirror and a few of the fixed mirror to generate intricate patterns of their survey.
Omni-directional scanners are more familiar means of horizontal sensors in supermarkets, where the package slipped through the glass or sapphire glass. There are a wide variety of omni-directional units available, which can be used for various test applications, from commercial applications to read barcode scanner a few inches from the industrial belt, where the drive scan can be several meters or more from your code.
Omni-directional scanners are also better at reading poorly printed bar codes or wrinkled Ripped.
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