Every day we meet with such a device as a scanner: in the store at the checkout, at the automatic entrance doors, at the elevators. In the office, one of the first assistants is also a scanner. So what is he really like? Let's try to understand the article.
What is a scanner?
A few decades ago, we could not even imagine that old faded photographs that are stored in grandmother's albums can be given a second life. All thanks to the device with the short name "scanner."
A scanner is a modern technical device, with which you can enter any information from paper onto a personal computer, and then, using special programs, edit and give the information the necessary look. Thus, the scanner can significantly save time. Indeed, for example, in order to print text in a standard format, it takes from two to five minutes. The scanner does this in about twenty seconds. Like any peripheral devices, scanners must be connected to a personal computer or other system that receives digital data.
Who invented the scanner
Like every subject, the scanner also has its own inventor. And before turning into a compact fashionable computer accessory, he went a long way in development.
In the middle of the XIX century, in 1856, a certain abbot named Giovanni Caselli, who lived in Italian Florence, invented an apparatus that could transmit any image at a certain distance. The device was called pantelegraf, and it was only a primitive device. The principle of the scanner of this kind was as follows: the picture that needed to be transferred was applied to a special drum with ink that transmitted current, and the picture was read with a needle.
The next round in the development of the scanner device happened in 1902. The German scientist Arthur Korn for the first time received the rights to photoelectric scanning technology, which is still known worldwide as telefax. The principle of operation was based on the following actions. The picture was fixed on a rotating drum. A light lamp moved along the drum. Its beam, passing through the picture and a special prism, fell on the selenium receiver.
Types of Scanners
Today there are several types of scanners:
- The very first scanner in the world was a drum. It was invented in the USA in 1957. The resolution of the picture was very low, only 176 pixels of black and white ink pigment. Modern drum scanners have highly sensitive components, thanks to which they can depict the smallest details. A picture or text can be retouched so many times until the result is completely satisfactory. Xenon or halogen beams are included with the drum scanner. Special requirements apply to their reflection. If a transparent document is scanned, then the lamps inside are working. When illuminating documents with a high reflective surface, lamps located on the outer perimeter come into effect.
- The most popular device is a flatbed scanner. It is he who stands in every office and is used to scan documents and graphic materials. This scanner is designed for formats up to A4. The principle of operation is based on a movable carriage, which moves along the glass on which the image is located. The information in encoded form falls on the photosensitive elements. They, in turn, analyze the data obtained for the presence of the primary colors of the spectrum. Modern models of flatbed scanners have the ability to instantly recognize text and reformat it to pdf files.
- Laser scanner. The most common in everyday life. We are under his supervision in stores, he opens us automatic doors with a motion sensor. The device is widely used in architecture, construction, in various social enterprises.
- Wide format scanners. These are mainly used by architects and builders in order to fully convey the image of the object and make the necessary changes without breaking the diagram into parts.
- Hand scanners. They were especially popular in the nineties of the last century. Their principle was based on the mechanical (manual) dragging of the scanner device over the surface of the paper. To make a quality picture, you had to hold your hand firmly.
- Book scanners. They are also called planetary, because such equipment is arranged in a special way. He does not need to contact documents. A specially installed highly sensitive sensor sees the document at a distance either entirely using an infrared beam, or views the data with a special laser ruler. Many have the function of leveling the page height. Basically, book scanners are used to scan ancient shabby documents that cannot be picked up or subjected to mechanical pressure.
- Network scanners. The only peripheral device family that can do without a computer. All information is transmitted and stored in special clipboards. Each user connected to the network can transfer their information or use the existing one.
Some devices are morally obsolete; humanity still uses something. One thing is clear: the input device - the scanner will always be on a par with the technical samples of primary necessity.
Image Type Classification
If the technical characteristics of the scanners can be divided into five main types, in terms of the processed images of these types, there are only two: black and white scanners and color.
Black and white devices work on a simple principle. A fluorescent lamp that gives white light illuminates the scanned image. Then the reflected light, passing through special lenses, falls on special photosensitive elements, which, in turn, fix the encoded information and transmit it to the computer.
Scanners that could transmit color images were much more difficult to enter the market. The first devices appeared in 1989, but they did not win popularity among users because of the price that was too high compared to black and white scanners. Their cost reached several tens of thousands of dollars. The color scanner device differs significantly from the achromatic counterpart, since the work is built on a special light filter. This filter is based on three colors: red, green and blue. To completely scan text or an image, the operation for each color is performed separately. As a result of passing the triple stage, a certain image image is obtained, which undergoes color correction. After that, the information is transmitted to the computer. In addition to the high price, color scanners have another drawback: the time to scan one document is increased three times. Problems can also occur when aligning colors in each of the passes. On the sheet, the image will be blurry and fuzzy.
The principle of the scanner
The device of the scanner and printer, sometimes forming a single complex, varies significantly. Like any computer accessory, it consists of mechanical and electrical parts, which together represent a rather complex structure. However, at first glance, the device and the scanner work quite simply. You can understand the principle of operation on the tablet type.
Before starting work, make sure that the device is connected to the computer. A scanner is an information input device, and to obtain an ideal result it is with the help of a computer that all the necessary settings are made.
The document to be scanned is placed with text or a pattern down on a special glass. As soon as you press the scan button, a chain reaction starts.
Under the glass are several mirrors fastened together, photosensitive sensors, lenses and a small light source that is attached to a movable trolley. This trolley comes in motion, rolling along the entire document. The light from the scanned paper is reflected and passed through a system of mirrors and lenses, and then sent to photosensitive sensors.
Each element of the scanned document has its own degree of illumination, and this information is transmitted to the main device in the form of a specific digital code. Then it is processed by special devices into binary code and appears on the personal computer as a copy of the just scanned document.
Dual purpose device
A popular device like a printer also has a place to be in our lives. Quite well-known, it nevertheless at some point lost ground, having teamed up with the scanner. This contributed to an increase in working space. The new sample was called the MFP - a multifunctional device, the printer and scanner in which were combined into a single mechanism.
Despite the combination, each device still has its own function. If the scanner is a device for inputting information into a personal computer, then the printer is a device for outputting data to paper media.
The quality of the data output by the printer, be it text or a picture, depends not only on the quality of the source material in the computer, but also on the sensitivity sensors built into the device itself.
Typically, a multifunction printer-scanner device is preferred for home use. It is useful for schoolchildren, students, teachers or representatives of economic professions in order to perform simple tasks that do not require improved technical characteristics.
For the same purpose, a copy machine and scanner are used in one device. If the task of the scanner is to enter information, then the purpose of the copier is to copy, make the required number of copies from one source of information.
Advanced MFP
On the shelves of electrical goods stores you can find an apparatus that is ready to perform the most complex office tasks. This is a multifunctional device with a printer, scanner and copier. Distinguish between such samples of home and industrial use. The technique combines many features:
- saves space, which is especially important at home;
- works with documents;
- prints and processes high quality photographs;
- an irreplaceable thing for schoolchildren and students whose parents are not ready to give round sums to private organizations that are involved, for example, in the printing of texts.
Most multifunctional devices with a printer, scanner and copier have the ability to send and receive data via wifi. At the same time, designers are trying to give the devices a stylish economical appearance so that it serves not only for work, but also fits perfectly into the interior. This is an advantage for home appliances.
Industrial devices, of course, are different. If you ever ever printed or edited documents in specialized office centers, you probably noticed a rather impressive size of the machine. This is the very MFP that has a large amount of power and is ready to work 24 hours a day without interruptions. The list of functions for office devices is practically no different from standard devices, but it greatly simplifies life.
Laser scanners
The scanner is a fairly wide profile device. Among the large number of types of this apparatus, the widest range of applications is with a laser scanner.
Such a scanner is a progressive type of device that is used in construction, surveying, even in the military and space fields. The principle of operation is quite simple at first glance: the laser beams directed at the object in question reach and fix the distance between all surfaces and the points that make up the object in space. Then the data is processed by the computer and displayed on the monitor. Laser scanning has many advantages:
- Low cost of work, and classic options are expensive.
- The speed of information processing using laser technology is several times higher.
- Highest estimation accuracy with minimal error.
- The laser scanner is a device with unique technical characteristics: they are able to accurately capture data even of microscopic dimensions.
- There is no interference with the laser beam: trees, dark, fog or rain will not cause an incorrect assessment of the object.
- No special conditions are needed. Laser shooting can be carried out from anywhere in space.
Despite the fact that the device of laser scanners is not particularly different, the technical characteristics of the devices are divided into several subspecies. So, for example, one type of scanner can be used to work with large objects, others are perfect for determining data from medium and small objects.
When buying a laser scanner, it is necessary to consider several points that will have a significant impact on future work. One of the important indicators of the device is the accuracy of measurements and the level of resolution. This affects the operation of the output device: the scanner captures the smallest details. It is also worth immediately dealing with the range and speed of scanning. Now many manufacturing companies are introducing additional options into their flagship copies, thereby increasing technical functionality, for example, the ability to connect a video camera or output information to several devices at the same time.
Barcode Scanner
Barcode scanners have taken a strong place in the field of trade and construction, logistics and accounting. The use of such devices makes it several times easier to enter data on goods or services. The device barcode scanner differs in technology. There are laser, LED and photo scanners.
LED scanner works as follows. An LED falls on the product barcode. The reflected light falls on a specially tuned sensitive matrix, which encrypts the data and displays them on the monitor. Both the scanner of the device and any additional accessories must be directly connected to the computer. The advantages of the LED type include low cost, high speed scanning and information processing, stroke recognition from 0.1 mm. There are also disadvantages, for example, the short scanning distance and the restriction on the recognition of large barcodes.
The principle of a laser-type scanner is similar to LED, but with the only difference being that the laser generates a denser luminous flux for recording data. Such devices are capable of recognizing barcodes of increased complexity at a distance of up to fifty centimeters. However, in terms of price, they will cost more.
The photo scanner is fundamentally different from its counterparts. Unlike previous versions, the photo scanner simply photographs the bar code and, on the basis of algorithms similar to computer ones, processes the received data, which it transfers to the user. You can photograph information from any angle, the data will still be recorded.
Barcode scanners can be stationary or not, wired or wireless, working on the functions of bluetooth or Wi-Fi.
Other types of scanners
In addition to common types of scanners, there are narrow-profile devices that are used in specialized fields.
Smartphone manufacturers are now reaching a new level of security by endowing their flagship products with retinal scanners. These are biometric technologies that protect your personal data from dishonest people or scammers, if, for example, you lose your phone. The technology itself was invented and proposed to the public in the distant 1936. Then ophthalmologist Frank Burch noted that the iris of each person is unique. And only in 1994, almost sixty years later, engineer John Duffman first patented a mathematical algorithm that is able to determine the differences in the iris.
The work of such scanners is based on the use of infrared radiation, which is sent to the pupil. The camera determines the color and the smallest details of the iris, and the system compares them with the sample in the database. If the options match, access is opened. . , , , . .
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3D scanners are gaining great popularity. Such technology appeared at the end of the 20th century, and the first test apparatus was assembled in the 60s of the same century. The scanner could not boast of special functions. Improvement occurred in the mid-80s. Lasers were added, additional sources of white light and blackout, which allowed to improve the vision of the scanned object. Cameras located at different angles capture the smallest details of the object from different angles. Further, all received pictures are saved, analyzed and assembled into a single three-dimensional model. There are contact and non-contact scanners. In the first case, the studied model should stand on a special plate. The second option uses a special light. It can be infrared radiation, x-rays or ultrasound.