synonymBar code scanner(Equipment used to scan barcode) generally refers to barcode scanner
Barcode scanner, also known as barcode readerBarcode scanning gun、Bar code scannerBarcode scanner and barcode reader.It is a reading device used to read the information contained in the barcode. It uses optical principles to decode the content of the barcode and transmit it to the computer or other devices through data lines or wireless means.It is widely used in supermarkets, logistics express delivery, libraries, etc. to scan the barcode of goods and documents.
Barcode scanner, also known as barcode scanner/reader, is a device used to read the information contained in the barcode. It can be divided into one-dimensional and two-dimensional barcode scanners.The structure of barcode scanner usually includes the following parts: light source, receiving device, photoelectric conversion component, decoding circuit, computer interface.The basic working principle of the scanning gun is that the light emitted by the light source shines on the bar code symbol through the optical system.The reflected light passes through the optical system and forms an image in thePhotoelectric converterThe decoder is interpreted as a digital signal that can be directly accepted by the computer.Except one, two-dimensional barcode scanner classification.It can also be classified as:CCD, full angle laser and laser handheld barcode scanner.
Laser scannerThe scanning window transparent mirror is made of special toughened materials, with smooth light transmittance and profound scenery. The overall plastic should be odor free, high temperature resistant, corrosion resistant, easy to scrub, and easy to operate.
Four technologies
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Bar code scanner
Common barcode readers usually use the following four technologies:Light pen、CCD、laserImage red light.
working principle
Light pen is the first handheld contact barcode reader, which is also the most economical barcode reader.
When in use, the operator needs to touch the light pen to the bar code surface, and send a small light spot through the lens of the light pen. When the light spot crosses the bar code from left to right, the light is reflected in the "empty" part, and the light will be absorbed in the "bar" part, so a variable voltage is generated inside the light pen, which is used for decoding after amplification and shaping.
advantage
Contact with the bar code to read, can be clear which is the read bar code;The length of barcode reading can be unlimited;Compared with other readers, the cost is lower;There are no moving parts inside, which is relatively solid;Small size and light weight.Disadvantages: The use of light pen will be subject to various restrictions, for example, it is not suitable for contacting and reading barcode in some occasions;In addition, the light pen can only play its role when reading the barcode with specified density and good printing quality on a relatively flat surface;Moreover, operators need to be trained before they can use it, such as reading speed, reading angle, and improper use pressure will affect its reading performance;Finally, because it must be read in contact, when the barcode is damaged due to improper storage, or there is a protective film on it, the light pen cannot be used;The first reading success rate of light pen is low and the bit error rate is high.
Reader principle
CCD is an electronic coupling device, which is more suitable for close and contact reading. Its price is less expensive than laser readers, and there are no moving parts inside.
The CCD reader uses one or more LEDs, and the light emitted can cover the entire bar code. The image of the bar code is transmitted to a row of light and sampled by each individual photodiode. The adjacent detection results are "black" or "white" to distinguish each bar or space, so as to determine the character of the bar code. In other words,The CCD reader does not read every "bar" or "empty", but the whole part of the bar code and converts it into a decoded electrical signal.
Advantages: Compared with other readers, CCD readers are cheaper, but they also have a wide density of reading bar codes and are easy to use.It weighs less than a laser reader, and unlike a stylus, it can only be read by touch.
Disadvantages: CCD reader is limited by its reading depth of field and reading width. It is difficult to read the barcode printed on the arc surface (such as beverage cans);In some occasions that require long-distance reading, such as the warehouse field, it is not very suitable;CCD has poor fall prevention performance, so the failure rate is high;When the barcode to be read is relatively wide, CCD is also not a good choice. Barcodes with long information or low density are easily beyond the reading range of the scan head, resulting in unreadable barcodes;Moreover, in some bar code readers with multiple LEDs, the failure of any LED will lead to the inability to read;Most CCD readers have low success rate of first reading and high probability of bit error.
Principle of laser gun
Laser Scanner It is relatively expensive among various scanners, but it can provide the highest functional indicators, so it is widely used in various industries.
Laser Scanner The basic working principle of the handheld laser scanner is that a beam of light is emitted through a laser diode and shines on a rotating prism or a mirror that swings back and forth. The reflected light passes through the reading window and shines on the barcode surface. The light returns to the reader after being reflected by a bar or space, and is collected and focused by a mirrorPhotoelectric converterIt is converted into an electrical signal, which will be decoded by the scanner or decoding software on the terminal.
The laser scanner can be divided into two forms: handheld laser guns are easy to connect and flexible to use. The fixed laser scanner is suitable for the occasions with the largest reading size and smaller barcode, effectively freeing hands for work.
advantage:Laser Scanner It can be used for non-contact scanning excellently. Generally, when the reading distance exceeds 30cm, the laser reader is the only choice;The laser reading bar code has a wide range of density, and can read the irregular bar code surface or through glass or transparent tape. Because it is non-contact reading, it will not damage the bar code label;Because of the advanced reading and decoding system, the first reading recognition success rate is high, the recognition speed is faster than that of light pen and CCD, and the recognition effect is good for the bar code with poor printing quality or fuzzy;Very low bit error rate (only about 1/3 million);The laser reader has good shockproof and fall proof performance, such as the SymbolLS4000 series scanner, which can prevent 1.5 meters of concrete from falling.
Disadvantages:Laser Scanner Its only disadvantage is that its price is relatively high, but if calculated from the sum of the purchase cost and the use cost, it is not very different from the CCD reader.
Image type red light
The image type red light bar code reader is a bar code reader that can replace the laser gun!!!Its scanning depth of field is up to 30cm, and with its scanning speed up to 300 times/second, it has excellent code reading performance.The unique image design makes its decoding ability extremely strong. The barcode that cannot be read by the general scanner can still be easily read by the image red light.Through the intelligent interface, the conversion of keyboard, RS232 serial port, USB and other interfaces can be realized simply by replacing the cable. At the same time, the laptop can also be directly connected.For special devices such as handheld computers, some models can be directly powered by built-in batteries, which solves the problem of insufficient power supply capacity of handheld computers.It can also be set and upgraded through software.Its rich data editing function can make the image red light scanner fully cooperate with the existing software of users.The excellent performance of the image type red light scanner plus its easy price will definitely be your best choice!!
Bar code scanner
Product features
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Bar code scanner
The barcode scanner has the following characteristics
(1) The scanning window transparent mirror is made of special toughened material, which is more shatter resistant and has a smoother light transmittance, making the depth of field longer; (2)The gun body plastic conforms to the national standard manufacturing process, so that it is odorless, high temperature resistant, corrosion resistant, easy to scrub, and the gun line can be removed with a pin, which is very convenient to operate;
⑶ The ergonomic design is perfectly reflected, the buzzer is louder (can be smaller), and the shock absorption is reasonably equipped from beginning to end, which can withstand repeated 2m road fall ground tests.
application area
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Barcode scanner is widely used in commercial POS cash register system, express warehousing logistics, books, clothing, medicine, bank insurance communication and other fields.Keyboard interface,USB interfaceandRS232 interfaceThree interfaces are available.The standard configuration of the product includes a scanning gun host,USB cable, manual and white bracket;Express companies warehousing logistics warehouse inventory supermarket stores books and clothing stores, etc., as long as there are bar codes, there are radium codes.
Bar code scanner
Development prospect
In recent years, the Internet of Things has become a hot field with rapid development.More and more people in the industry have widely recognized the market prospect of the Internet of Things. Although many people think that the Internet of Things has become popular, many people think that it is just an extravagant hope that the Internet of Things will be widely realized in many fields as soon as possible,But now as we all know, the Internet of Things has indeed been widely used in some aspects.
Imagine that what we are living now is a rapid development of science and technology. It is no exaggeration to say that every day there will be changes with each passing day. If we cancel all supermarkets nowBar code scannerInstead, we continue to use the cashier to manually input the number of each commodity, so that the long queue in front of the supermarket's cashier will bring us what a boring shopping experience.At a smaller level, people will definitely reduce their queuing to buy goods in supermarkets, and at a larger level, it can directly lead to a decline in consumption levels.It is not conducive to the stable development of the economic level.Moreover, if we also cancel barcode scanners when we go to shopping malls to buy clothes, the security of goods will be greatly reduced, and the theft rate will be greatly improved.If we do not have a barcode scanner to track the location of the package when we shop online, who can be sure that the goods we buy can accurately reach the buyer's home?
Nowadays, barcode scanning industry technology has been widely used in many fields and industries, such as retail industry, manufacturing industry, logistics, medical care, warehousing, and even security.Recently, the most popular is the two-dimensional code scanning technology on WeChat, which can quickly and accurately identify information.After your mobile phone is installed with a new version of WeChat (including QR code software), you can use it directlyMobile cameraTo scan and identifyQR codeInformation contained.Each WeChat user can generate its own unique QR code. When you encounter a QR code, the mobile phone can scan the information of the person you want to find accurately, which can effectively prevent adding unknown people as friends.
Now many fast food restaurants, such as KFC and McDonald's, have taken the lead in introducing two-dimensional code scanning electronic coupons to replace the previous electronic coupons.Because there were so manyElectronic CouponThere are time restrictions, but there are no restrictions on the number and location, which has led to the proliferation of electronic coupons. The current two-dimensional code scanning coupons are no longer limited by time and region, providing convenience for more consumers, but also large-scale promotions for businesses themselves.
It can be seen that the prospect of barcode scanner will be limitless, because it fully conforms to the mentality that people need to do the most convenient thing in the shortest time under the fast pace of modern society, and it will also be the trend of the times.
Bar code scanner
working principle
The common flat bar code scanner is generally composed of light source, optical lens, scanning module, analog digital conversion circuit and plastic shell.It uses photoelectric elements to convert the detected optical signal into electrical signal, and then passes the electrical signal throughAnalog digital converterIt is converted into digital signal and transmitted to the computer for processing.When scanning an image, after the light source shines on the image, the reflected light passes through the lens and converges on the scanning module. The scanning module converts the optical signal into an analog digital signal (that is, voltage, which is related to the intensity of the received light), and points out the gray range of that image number.At this time, the analog digital conversion circuit converts the analog voltage into a digital signal and transmits it to the computer.The color is quantized by 8, 10, and 12 bits of RGB three colors, that is, the signal is processed into the image output of the above bits.If there are higher quantized digits, it means that the image can have richer levels and depth, but the color range has exceeded the recognition ability of the human eye. So within the range of resolution, for us, the effect of the barcode scanner with higher digits is that the color is smooth and can see more picture details.
Product parameters
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Different products have different parameters.For details, please visit the website of the relevant scanner manufacturer.
type
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Bar code scanner
There are many types of barcode scanners, including the following:
Handheld barcode scanner
The handheld barcode scanner is a product formed by the technology introduced in 1987, and its shape is very similar to the barcode scanner used by the cashier in the supermarket.The vast majority of handheld barcode scanners use CIS technology, with an optical resolution of 200dpi, and there are many types of black and white, grayscale, and color, of which the color type is generally 18 bit color.Some high-end products also use CCD as a photosensitive device, which can achieve true color and good scanning effect.
Small roller bar code scanner
This is the intermediate product of handheld barcode scanner and desktop barcode scanner (a new product has emerged in recent years, which is called notebook barcode scanner because of its built-in power supply and small size). The vast majority of these products use CIS technology, with an optical resolution of 300 dpi. There are two types of color and grayness, and the color model is generally 24 bit color.There are also a few small roller bar code scanners that use CCD technology, and the scanning effect is obviously better than that of CIS technology products, but due to structural constraints, the volume is generally significantly larger than that of CIS technology products.The small roller design is to fix the lens of the barcode scanner, and the moving objects to be scanned are scanned through the lens. During operation, like the printer, the objects to be scanned must pass through the machine and then be sent out. Therefore, the scanned objects cannot be too thick.The biggest advantage of this barcode scanner is that it is small in size, but it has many limitations in use. For example, it can only scan thin paper, and the range cannot exceed the size of the barcode scanner.
Platform barcode scanner
Also known as flat bar code scanner and desktop bar code scanner, most of the bar code scanners on the market are flat bar code scanners, which are now the mainstream.The optical resolution of such barcode scanners is between 300dpi and 8000dpi, the color bits range from 24 to 48, and the scanning format is generally A4 or A3.The advantage of the flat plate type is that as long as the upper cover of the barcode scanner is opened, books, newspapers, magazines and photo negatives can be placed on it for scanning, which is quite convenient, and the scanning effect is the best of all common types of barcode scanners.
Bar code scanner
There are also large spaghetti bar code scanners, pen bar code scanners, bar code scanners, negative bar code scanners for large format scanning (note that it is not a flat bar code scanner that can be fully scanned, and the effect is much better, and the price is of course expensive), physical bar code scanners (not a flat bar code scanner with physical scanning capability, which is somewhat similar to a digital camera),There are also many roller bar code scanners mainly used in the field of industrial printing and typesetting.
Interface type
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Bar code scanner
The common interface types of barcode scanner are as follows:
SCSI (Small Computer Standard Interface)
The maximum number of connected devices of this interface is 8. Usually, the maximum transmission speed is 40M/S, which is fast. Generally, high-speed devices are connected.The installation of SCSI devices is more complicated. Generally, a SCSI card is added to a PC, which is prone to hardware conflicts, but it is powerful.
EPP (Enhanced Parallel Interface)
An enhanced bidirectional parallel transmission interface with a maximum transmission speed of 1.5Mbps.The advantage is that no other card is needed in the PC, the number of connections is unlimited (as long as you have enough ports), and the device is easy to install and use.The disadvantage is that the speed is slower than SCSI.This interface is easy to install and use, so it can be replaced in the low and middle end where performance requirements are not highSCSI interface。
USB (Universal Serial Bus Interface)
Up to 127 peripherals can be connectedUSB1.1The standard maximum transmission speed is 12Mbps, and a secondary channel is used to transmit low-speed data.In the future, if there is a USB2.0 standard bar code scanner, the speed may be extended to 480M/s.With hot plug function, plug and play.The barcode scanner with this interface is gradually popularized with the establishment and promotion of the USB standard pushed by Intel.
PS2 (keyboard interface)
Similar to USB usage, it needs a smart head to switch it. Generally, it comes with the purchase of a scan gun.Many companies still use the PS2 interface.
resolving power
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Bar code scanner
The resolution of barcode scanner should be determined from three aspects: optical part, hardware part and software part.In other words, the resolution of the barcode scanner is equal to the resolution of its optical components plus the resolution obtained by its own processing and analysis through hardware and software.
Optical resolution refers to the actual number of light points that can be captured by the optical components of the barcode scanner within each square inch area. It refers to the physical resolution of the barcode scanner CCD (or other photoelectric devices), and is also the true resolution of the barcode scanner,Its value is the value obtained by dividing the pixel points captured by the photoelectric element by the maximum horizontal scanning size of the barcode scanner.For example, for a barcode scanner with a resolution of 1200DPI, the resolution of its optical part is only 400-600DPI.The resolution of the expansion part is jointly generated by the hardware and software. This process is generated by the computer's analysis of the image and mathematical filling of the blank part (this process is also called interpolation processing).
Optical scanning and output are one-to-one. What is scanned, what is output.After the computer software and hardware processing, the output image will become more realistic and the resolution will be higher.At present, most bar code scanners sold on the market have software and hardware expansion functions for resolution.Some bar code scanners advertise 9600 × 9600DPI, which is only the maximum resolution obtained by software interpolation, not the true optical resolution of the bar code scanner.So for barcode scanner, its resolution includes optical resolution (or optical resolution) and maximum resolution. Of course, we are concerned about optical resolution, which is hard work.
When we say that the resolution of a bar code scanner is up to 4800DPI (this 4800DPI is the sum of optical resolution and software difference processing), it means that 4800 × 4800 pixels can be collected on a scanning format of 1 square inch when using the bar code scanner to input images.For a scanning area of 1 inch square, the image size generated after scanning with a resolution of 4800DPI is 4800Pixel × 4800Pixel.When scanning an image, the higher the scanning resolution is set, the finer the effect of the generated image is, and the larger the generated image file is, but the more interpolation components are.[1]
Photoelectric device
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At present, there are four types of photosensitive devices used by barcode scanners in the market:Photomultiplier tube, silicon oxide isolation CCD, semiconductor isolation CCD, contact photosensitive device (CIS or LIDE).
The mainstream is two kinds of CCD, and its principle is simple: thousands to tens of thousands of phototransistors are integrated on a single silicon crystal. These phototransistors are divided into three columns, which are respectively covered with red, green and blue color filters to achieve color scanning.Compared with the two kinds of CCD, the silicon oxide isolation CCD is better than the semiconductor isolation CCD. Those who are familiar with physics naturally know why.To put it simply, the leakage phenomenon between semiconductor CCD triodes will affect the scanning accuracy. Isolation with silicon oxide will greatly reduce the leakage phenomenon (this is insulator). Of course, it is better to add temperature control, because both semiconductor and conductor are generally temperature sensitive, and the conductivity will generally improve when temperature rises.At present, most of the mainstream markets are used for semiconductor isolation CCD, and there are few silicon oxide isolation CCD, apparently because of the high cost.If you want to know the effect of a barcode scanner, it is very important to know what kind of photoelectric element is used for the barcode scanner, even if it is the same as the semiconductor isolation quality.
Contact type photosensitive device, which usesPhotosensitive materialGenerally, the production cost of cadmium sulfide, which we use to manufacture photoresistors, should be much lower than that of CCD (this is why CIS barcode scanners with the same accuracy are always much cheaper than CCD barcode scanners on the market).The scanning distance is short, the scanning definition is low, and sometimes it can not reach the nominal value. The temperature change is easy to affect the scanning accuracy. These are the fatal problems of this barcode scanner.Those who are familiar with physics should know that the leakage phenomenon between the resistances of cadmium sulfide is larger than that of semiconductor insulation, which also reduces the accuracy.
Photomultiplier tubeThe photosensitive material is mainly cesium oxide.Its scanning accuracy, even the degree of temperature influence and noise are the best, but the price is also the most expensive.Ordinary users like me have always dreamed of it. The price is too expensive, so we will skip its specific technical features here.
The photoelectric device of a bar code scanner is an important factor to determine its performance. Other factors such as control circuit and software are also important.It may be difficult to understand these materials directly.We often can only know a limited amount of content (trade secrets). When we judge the performance of a barcode scanner, we can only know it by actual operation and evaluation software.
type
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In recent years, domestic major shopping malls, chain stores and other commercial enterprises have realized the huge benefits of commercial POS system to commercial enterprise management, and have built commercial POS network systems.For the design and installation principle of the network system, all professional publications have detailed introductions. Here we mainly talk about how to select the commercial barcode scanner as the front-end data acquisition part of the commercial POS system.
Common commercial barcode scanners include:
CCD scanner
CCD scannerIt uses the principle of photoelectric coupling (CCD) to image the bar code printed pattern, and then decode it.Its advantages are: no shaft, motor, long service life, low price.
When selecting a CCD scanner, the most important parameters are:
Depth of field: Since the imaging principle of CCD is similar to that of a camera, if the depth of field needs to be increased, the lens should be increased accordingly, so that the CCD volume is too large to operate.Excellent CCD shall be readable without sticking to the bar code, and shall be of moderate size and comfortable operation.
Resolution: If the CCD resolution is to be improved, the unit element of the photosensitive element at the imaging place must be added.The low-cost CCD is usually 5 pixels. It is enough to read EAN, UPC and other commercial codes, but it will be difficult to read other codes.The middle CCD has 1024pixel, some even reach 2048pixel, and can distinguish the bar code with the narrowest unit element of 0.1mm.
Laser handheld
The laser handheld scanner is a single line scanner using laser diode as the light source. It mainly has two types: rotating mirror type and vibrating mirror type
The representative brand of the rotating mirror type is ACAN 8500, which uses a high-speed motor to drive a prism group to rotate, so that the single point laser emitted by the diode becomes a line.This laser line sweeps to the bar code itself, the black bar code absorbs most of the laser, and the white bar code reflects most of the laser. At the same time, the reflected light passes through the optical lens in the "engine", reflects, and focuses on a photoelectric triode. Observed in the time domain, the photoelectric triode laser output on the black bar code is low, and the photoelectric triode on the white belt is high.After several times of amplification, it is shaped into a rectangular wave, which corresponds to the scanned barcode.The waveform obtained is then transmitted to the "decoder" part through the data line."Decoder" is actually a single chip computer, which mainly depends on the interrupt and the single chip computer counter to record the waveform jump time. The collected data series will be digitally decoded in the next scan or scan back, and the corresponding barcode will be decoded mainly based on the time proportion obtained by these counters. In practical application, there are many kinds of barcodes, and irregular wrinkles such as bubble packaging will be encountered,Therefore, the decoding part needs a certain fault tolerance, but it cannot generate error code.At present, the decoder microcontroller is generally divided into 8 bits and 32 bits. The 8 bit advantage lies in the price, and the 32 bit advantage lies in the speed.The laser bar code market is a mixture of good and bad people, following the lead of the ccd scanner. The price has been falling again and again, and copycat is rampant. However, there are several powerful manufacturers in China. Consumers need to carefully consider what brand to use and choose the most suitable one.
The production cost of the vibrating mirror type is lower than that of the rotating mirror type, but the laser gun based on this principle is not easy to improve the scanning speed, which is generally 33 times/second.Individual models, such as OPTION, can reach 100 times/second. The representative brands are Symbol, PSC and OPTION, and the most representative is SYMBOL 2208
Commercial enterprises are choosingLaser scannerThe most important thing is to pay attention to the scanning speed and resolution, while the depth of field is not the key factor.Because when the depth of field is increased, the resolution will be greatly reduced.An excellent handheld laser scanner should have a high scanning speed and a high resolution within a fixed depth of field.
All angle laser
The omni angle scanner is a bar code scanner that refracts the laser emitted by the laser diode or has multiple scanning lines through the optical system. Its main purpose is to reduce the labor of the payee to align the bar code when entering the bar code data. When selecting, attention should be paid to the distribution of the scanning line speckle:
1. There are several lines in one directionParallel line
2. Multiple scanning lines pass through a certain point
3. The interpretation probability of each point tends to be consistent within a certain space
All angle scanners that meet the above three points must be the preferred application for businesses.
Mobile phone barcode
Mobile barcode scannerIt can scan bar codes to various smart phones and integrate with them, making mobile phones transformdata collectorIt can be well applied to express logistics, medical management, home appliance after-sales, sales management, government affairs and other industries to help enterprises improve mobile service efficiency and reduce scale costs.
Related technologies
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Barcode is a set of bar and space symbols arranged according to certain coding rules to represent information composed of certain characters, numbers and symbols.Bar code system is composed of bar code symbol design, production and scanning readingAutomatic identification system。Barcode technology has the following advantages:
1. Fast input speed: compared with keyboard input, the bar code input speed is 5 times that of keyboard input, and can achieve "real-time data input".
2. High reliability: the error rate of keyboard input data is one in three hundredOptical character recognitionThe technical error rate is one in ten thousand, while the code error rate of bar code technology is less than one in a million.
3. Large amount of information collected: The traditional one-dimensional barcode can collect information of dozens of characters at a time, while the two-dimensional barcode can carry information of thousands of characters, and has certain automatic error correction capability.
4. Flexible and practical: Bar code identification can be used alone as a means of identification, or can form a system with relevant identification equipment to realize automatic identification, or can be connected with other control equipment to realize automatic management.
In addition, bar code labels are easy to make, there are no special requirements for equipment and materials, identification equipment is easy to operate, no special training is required, and the equipment is relatively cheap.
