The Japanese automaker Denso Wave created the QR code, also known as a two-dimensional barcode, in 1994. QR stands for "rapid response code."
A barcode is an optical label that can be read by a computer and contains data about the object to which it is attached.
In reality, QR codes frequently contain information for a tracker, location, or identifier that directs users to a website or application.
To store information efficiently, QR codes use four specified encoding modes: numeric, alphanumeric, byte/binary, and kanji; extensions may optionally be used. A light source and photodiode are positioned next to each other in the tip of a pen to make up pen-type readers. The person holding the pen must move the tip across the bars at a comparatively constant speed in order to read a barcode. As the tip moves across each bar and space in the printed code, the photodiode measures the amount of light that is being reflected back from the light source. The widths of the bars and spaces in the barcode are measured using the waveform that the photodiode produces. White gaps reflect light, whereas dark bars in the barcode absorb light. As a result, the voltage waveform produced by the photodiode depicts the bar and spacing pattern in the barcode. This
Similar to how dots and dashes in Morse code are decoded, this waveform is decoded by the scanner.
a laser scanner
also consider laser scanning
Laser scanners move the laser beam across the barcode in a back-and-forth motion. A photo-diode is used to gauge the strength of the light reflected back from the barcode, just like with pen-type readers. The light that the reader emits is rapidly altered in brightness with a data pattern in both pen readers and laser scanners. The photo-diode reception circuitry is made to only detect signals that have the same modulated pattern.
CCD viewers (also known as LED scanners)
The array of several small light sensors used by charge-coupled device (CCD) readers is arranged in a row in the
Because it can store more data than a conventional UPC barcode and is faster to scan than a typical UPC barcode, the Quick Response system gained popularity outside of the automobile industry.
Applications include document management, general marketing, product tracking, item identification, and time monitoring.