free download PNG images :Barcode

Bar code is an optical, machine-readable representation of data. Data usually describes some information about the object carrying the barcode. Traditional bar codes display data systematically by changing the width and spacing of parallel lines, and can be called linear or one-dimensional (1D). Later, two-dimensional (2D) variants were developed using hexagons and other geometric patterns called matrix code barcodes, although they did not themselves use bar charts. Initially, scanning was done only through a special optical scanner called a barcode reader. Later, application software can be used for devices that can read images, such as smartphones with cameras.

The bar code was invented by Norman Joseph woodland and Bernard silver, and was patented in the United States in 1952 (US patent 2612994). The invention is based on Morse code, which has been extended to thin strip and thick strip. However, it took more than 20 years for the invention to be commercially successful. In the late 1960s, the American Association of Railways launched an early use of a bar code in an industrial environment. The scheme, developed by general telephone and electronic (GTE), is called kartrak ACI (automatic vehicle identification). The scheme includes placing color stripes on steel plates fixed on the side of railway vehicles in various combinations. Each car uses two boards, one on each side, and color stripes to arrange and code information such as ownership, equipment type and identification number. As the car passes, the boards are read by a roadside scanner located at, for example, the entrance to a sorting yard. About ten years later, the project was abandoned because its long-term use proved that the system was unreliable.

When bar codes are used to automate supermarket checkout systems, they have been commercially successful, and this task has become almost universal. Their use has been extended to many other tasks, commonly known as automatic identification and data capture (AIDC). In June 1974, the universal commodity code (UPC) barcode, which is now commonly used, was scanned on a package of Wrigley Company gum for the first time. QR code is a special type of 2D barcode, which has become very popular recently.

Other systems have entered the AIDC market, but the simplicity, versatility and low cost of barcodes limit the role of these other systems, especially after the advent of RFID technology in 2000.

In 1948, Bernard silver was a graduate student at Drexel Institute of technology in Philadelphia, Pennsylvania. At that time, the company wiretapped the president of the local food chain, food fair, to ask a dean to study a system that automatically reads product information at checkout. Silver informed his friend Norman Joseph woodland of the request and they began to study systems. Their first system used UV ink, but the ink faded too easily and was expensive.

Woodland was convinced that the system could be further developed, so he left Drexel, moved into his father's Florida apartment, and continued to study the system. His next inspiration came from Morse code, which he created with sand on the beach. "I just extend points and points down and draw thin and thick lines in them." To read them, he used the movie's optical sound track technology, using a 500 watt incandescent light bulb that passes through paper and onto the far end of the rca935 photomultiplier tube (from the movie projector). He later decided that if the system was printed as a circle rather than a straight line, it would work better, allowing scanning in any direction.

On October 20, 1949, woodland and silver filed a patent application for "classification instruments and methods", which describes the linear and eyelet printing patterns and the mechanical and electronic systems needed to read the codes. The patent was issued as US patent 2612994 on October 7, 1952. In 1951, woodland moved to IBM and tried to arouse IBM's interest in system development. The company eventually commissioned a report on the idea, which concluded that it was both feasible and interesting, but that processing the information would require equipment for some time to come.

Bar codes such as UPC have become ubiquitous elements of modern civilization, which has been enthusiastically adopted by stores around the world. With the exception of fresh produce from grocery stores, most items now have UPC barcodes. This can help track merchandise and reduce shoplifting involving price tag exchanges, although shoplifters can now print their own barcodes. In addition, retail chain membership cards (mainly issued by grocery stores and professional "big box" retail stores, such as sports equipment, office supplies or pet stores) use bar codes to uniquely identify consumers, thus realizing personalized marketing and better understanding of individual consumers' shopping patterns. At the point of sale, shoppers can get product discounts or special marketing offers at the address or email address provided at the time of registration.

They are widely used in healthcare and hospital environments, ranging from patient identification (accessing patient data, including medical history, drug allergy, etc.) to creating soap notes with bar codes to drug management. They are also used to facilitate the separation and indexing of documents for imaging in batch scanning applications, track the tissue of species in biology, and integrate with dynamic scales to identify items being weighed in conveyor belts for data collection.

They can also be used to track objects and people. They are used to track car rentals, aircraft luggage, nuclear waste, registered mail, EMS and parcels. Bar code tickets allow the holder to enter the playground, cinema, theater, open market and vehicles, and are used to record the access of vehicles from the rental facilities. This makes it easier for the owner to identify duplicate or fraudulent tickets. Barcodes are widely used in shop floor control applications where employees can scan work orders and track time spent on work.

Bar code is also used in some non-contact one dimension and two dimension position sensors. A series of barcodes are used in some absolute one-dimensional linear encoders. The barcode is packed tightly enough so that the reader always has one or two barcodes in its field of view. As a kind of reference mark, the relative position of bar code in the reader's field of view provides incremental accurate positioning, and in some cases has sub-pixel resolution. The data decoded from the barcode gives an absolute rough position. "Address carpet" (such as Howell's binary pattern and Anoto dot pattern) is a two-dimensional barcode designed to enable readers to find it even if it only occupies a small part of the whole carpet in the reader's field of vision. Absolute position and rotation of X, y in carpet.

2D barcodes can embed hyperlinks into web pages. It is possible to use a powerful mobile phone to read patterns and browse linked websites, which can help shoppers find the best prices for goods nearby. Since 2005, airlines have used IATA standard 2D barcode (bcbp) on boarding passes. Since 2008, 2D barcode sent to mobile phones has made electronic boarding passes possible.

Some applications for barcode are disabled. In the 1970s and 1980s, software source code was sometimes encoded as barcode and printed on paper (cauzin softstrip and paperbyte are barcode symbol systems specially designed for this application). In 1991, barcode Butler Computer game system used any standard barcode to generate combat statistics.

As part of the post modernist movement, artists used barcodes in their art, such as Scott Blake's barcode Jesus.