![]() Large field-of-view readers use high-resolution industrial cameras to concurrently collect several bar codes. Video camera readers use tiny video cameras equipped with the same CCD technology as CCD barcode readers, but instead of a single row of sensors, a video camera employs hundreds of rows of sensors stacked in a two-dimensional array to form a picture. They decipher the barcode using a camera and image processing algorithms. Two-dimensional image scanners are a more recent advancement in barcode reader technology. LED scanners may also be manufactured using CMOS sensors and are gradually displacing previous laser-based readers. The critical distinction between a CCD reader and a pen or laser scanner is that the CCD reader measures ambient light produced by the barcode, while pen or laser scanners measure reflected light of a particular frequency generated by the scanner. Each light sensor in the CCD reader is incredibly tiny, and since hundreds of sensors are lined up in a row, the reader generates a voltage pattern equal to the pattern seen in a barcode by successively measuring the voltages across each sensor in the row. Each sensor determines the brightness of the light directly in front of it. ![]() In both pen readers and laser scanners, the reader's light is quickly modulated with a data pattern, and the photodiode receive circuitry is configured to detect only signals with the same modulated pattern.ĬCD monitors (also known as LED scanners)ĬCD readers use an array of hundreds of tiny light sensors lined up in a row in the reader's head. As with the pen-type reader, a photodiode is used to determine the intensity of light reflected by the barcode. Scanning back and forth over the barcode with the laser beam. The scanner decodes this waveform in a similar fashion to how Morse code dots and dashes are deciphered. Because dark bars absorb light and white spaces reflect it, the voltage waveform created by the photodiode is a representation of the barcode's bar and space pattern. The photodiode creates a waveform that is utilized to determine the barcode's bar and spacing widths. As the tip passes each bar and space in the printed code, the photodiode detects the intensity of the light reflected back from the light source. To read a barcode, the individual holding the pen must move the tip at a roughly regular pace over the bars. ![]() Pen-style readers are made up of a light source and a photodiode that are attached to the tip of a pen. Additionally, virtually all barcode readers have decoding circuitry that analyzes the picture data given by the sensor and outputs the barcode's information to the scanner's output port. As is the case with a flatbed scanner, it is composed of a light source, a lens, and a light sensor for converting optical impulses to electrical signals. (or barcode scanner) is an optical scanner that is capable of reading printed barcodes, decoding the data contained inside the barcode, and transmitting the data to a computer. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |