The main characteristics of the scanner and their types

What if you needed to send an e-mail printed on paper? Probably everyone already knows such a device as a scanner. It more than once helped people save old photos that our grandfathers and grandmothers were doing, translating some important documents into the electronic format without having their source on the PC.

In general, the scanner is a useful thing and is now indispensable in many offices. To properly determine what model you need, you need to study the basic characteristics of the scanner.

What is it?

It is better not to refer to scientific terms, but to explain in simple language what kind of device it is. The scanner is responsible for executing the reading process, which is directed to a flat data carrier (for example, paper). In the end, the user receives a digital document for transmission at a distance or in an electronic format. Scanning leads to the creation of a digital image of the external image of the object due to the ADC. After that, the picture is sent to the computer using an input / output system.

First attempts

Few people know, but the main characteristics of the scanner were known to researchers since 1857. Then an alternative to the modern device was created by the abbot from Florence Giovanni Caselli. His device worked very primitively on current technologies. Then, in order to transfer the image to a distance, it was necessary to apply it to the drum with the help of conductive ink, and then count the picture using a needle. Such a device was called a pantheraph.

Already half a century later the German physicist conducted his experiment, during which the facsimile was patented. Arthur Korn developed a technique for photoelectric scanning. Its principle was not simple: the picture was attached to the same drum, but it was already transparent. The lamp was so fixed that the stream of light could move. He passed through the original image and headed to the selenium photodetector, and then penetrated through the prism and the lens.

The faster the semiconductors developed, the sooner the photodetector improved. Despite the fact that later invented the tablet method, the principle itself remained virtually unchanged.

Characteristics

Before you deal with the species, you need to pay attention to the technical specifications of the scanner. There is a whole spectrum of them, and there is no generally accepted classification. Each parameter depends on the purpose of the device. Nevertheless, there are the main characteristics by which the scanner should be selected. Among them, speed of operation, color depth, resolution of the resulting image, etc.

Beauty in Detail

The characteristics of the scanner are varied, but the resolution is one of the main parameters. In simple language: this property is responsible for the size of the smallest details of the picture that will be transmitted during the scan. The resolution is specified in dpi. This value shows the number of visible dots per inch of the picture. Usually the manufacturer indicates the performance of all three resolutions:

• Mechanical;
• Optical;
• Interpolation.

The first is necessary in order to determine the placement of the carriage with a CCD ruler while moving around the image. The fact that the mechanical resolution is twice the optical one, the manufacturer uses against an incompetent user. In TX, he indicates that the optical value is 300x600 dpi. But if the device does not have interpolation, it will work with a minimum value of 300 dpi.

Interpolation resolution is responsible for the size that can be obtained when the image is scaled 16 times. In principle, this is the least important parameter, and it practically does not carry any additional data. But also its manufacturer can use against the buyer, pointing to a box of 4800 dpi. Such a figure can impress an ignorant person. But anyone who does not know the characteristics of the scanner, but is going to buy this device, should take into account that the real optical value can be only 300 dpi.

The main parameter is the optical resolution. To determine it, you need to calculate the concentration of the elements in the photosensitive ruler. To do this, you need to divide the number of parts on it by its width. This parameter, as mentioned earlier, is the most significant in determining the detail of the picture. Therefore, it can rarely be found on the box with the device, as both the manufacturer and the seller try to hide the real indicators.

"Dry" numbers

As mentioned earlier, it is not easy to choose such a device. The characteristics of scanners can confuse an inexperienced buyer, so before buying it is better to understand each parameter. The next after resolution is the bit depth, or the depth of the hue. This characteristic indicates the number of bits that are required to store color information about each pixel. The black-and-white scanners need the least memory. They have one rank. Monochrome is slightly larger - 8, and color - 24 bits. Scanners in a more expensive segment can be 36-bit.

The depth of color is external and internal. It is these indicators that indicate the manufacturer. The internal is characterized by the width of the analog-digital transformer, helps to determine the number of colors that the scanner can "see". External depth is the number of shades that the device can transmit to a PC.

If you need a device in the office or home, the usual bit width is 24 bit. If you need a scanner in printing and similar organizations, it is better to look for a device for 48 bits.

Optical density

This scanner does not end there. There is a maximum optical density. If you do not go into details and scientific explanations, this is the ability of the device to scan dark pictures: the more sensitive the device, the better the dark areas of the image are digitized.

Along with this parameter there is an interval of optical density. It can be calculated with a decimal logarithm. It is equal to the ratio of the amount of light incident on the original to the amount of light reflected. On average, the range for 24-bit capacity should be 1.8-2.3 D.

Speed

This parameter is also often forgotten to indicate or at all graft. However, the scan rate depends on several factors. Primarily this resolution and the size of the script. The speed can indicate the number of pages per minute or simply the time at which one sheet is processed. There is also a measurement of the scanned lines per second.

The size of the scanned area can also be varied. The most common solution is the A4 sheet. Such models are found in offices and homes. Any enterprises can use the A3 format. For handheld scanners, the strip size is 11 cm.

Interface

Not always the characteristics of the scanner are of particular importance. In this category, you can send a device parameter such as an interface. It can be of several kinds. This includes its own interface from the developer. It was used earlier in scanner models. Its popularity faded after it became possible to update the PC operating system. This was due to the fact that after the release of a particular scanner, the scanner lost the optimization of its interface to another system, which means it did not function at all.

The next interface has a parallel port, which can now be found in younger samples of flatbed scanners. These devices are mediocre enough and stand out nothing. They are usually used to scan photos or pairs of pages of text.

The PCMCIA interface can also be found infrequently, but SCSI remains the standard for devices with high quality and performance. Now, with this interface, more powerful machines with 30 and 36-bit capacity are produced.

USB-interface - the latest and most fashionable option. It is actively recommended for many models, but not good enough for high-performance devices.

Light source

This parameter is rarely taken into account when selecting a scanner. There are three types of lighting:

• Xenon;
• Fluorescent;
• LED light.

Xenon lamps have small dimensions, they serve for a long time and have a short warm-up time. Fluorescent lighting is quite cheap, but it will also last a very long time. LEDs are small, they consume little energy and quickly heat up. Usually it is the latest LED scanners that are considered to be better.

Diversity

After the scanner itself appeared, it began to be modified and take different forms. Now this device can be classified according to a number of parameters. Types of scanners and their characteristics have now become generally accepted, and so far no technological innovations in this area have been observed.

To break these devices into categories, you need to study the following signs:

• Method of image formation;
• The structure of the kinematic mechanism;
• A variety of images;
• Characteristic of the original;
• Interfaces: hardware and software.

Kinds

So, for all the above parameters, you can choose a scanner for yourself. He can be:

• Tablet;
• Book;
• Manual;
• Sheet-straight;
• Planetary;
• Drum;
• Ultrasound, etc.

In general, there are a lot of scanner types. We will talk about the main and most popular.

Tablet at the moment is the most popular and convenient. Usually models of this type are very high-quality and fast. Externally similar to the tablet, and therefore received the name. To scan an image with such a device, you need to open the lid, put the sheet down on the glass, close the lid and press "start".

The handheld scanner does not have an engine. Therefore, to process the image, you need to move it yourself. The main advantage of such models is their price. But there are too many shortcomings: poor resolution, low scanning quality and low speed.

The book scanner is designed to process brochure documents. To scan the necessary information, it must be placed not down "face", as in the tablet, but upward. The quality is very good.

The scribe scanner is not very comfortable. To process the document, the sheet is inserted into the slot and pulled through the shafts inside. This scanner works with certain formats and separate sheets.

The planetary apparatus works with papers that are easy to damage. It eliminates contact with the object, due to which it is possible to preserve the integrity of the material.

Drum devices are found in printing enterprises and produce a high-quality image. Slide scanners work with film slides. Bar code scanners we meet every time we arrive at the store at the cash register. 3D device is something newfangled. It can scan real objects that are digitized and reincarnated into a three-dimensional model. Ultrasound scanner is a famous ultrasound used in medicine for the study of internal organs.

Four in one

There is a multifunction device (MFP), which combined a copy unit, facsimile mechanism, printer, scanner. Its characteristics are different. Basically, such devices can be inkjet, laser or LED based on printing technology. Like any scanner, the MFP can be colored or monochrome.

The main advantage of such a device is the saving of a place at home or in the office. The user does not need to move paper from one place to another. It is convenient to work with one device. Also, the IFIs have a fairly small price, relative to the amount that would have to be paid for each purchase of each device.

New in 2016

When you are familiar with the characteristics of the scanner, you can start searching for this device. This year, there were many new models that may interest the user. For example, the HP ScanJet scanner, whose performance is impressive, can cost only 2,000 rubles. In this case, you will be able to access the device with a depth of color scanning of 48 bits, a popular USB 2.0 connector and compatibility with many operating systems. In general, HP scanners, whose characteristics have always been at the highest level, are the leaders in the market in this segment. The company also has excellent models of multifunctional devices.

This year, the market appeared and those who impressed not only functions, but also the price. The characteristics of the Epson Perfection V850 Pro scanner are indeed very high. In addition to the fact that this tablet device has an adapter for film sliders and a USB 2.0 interface, its main characteristic is the resolution of 6400 × 9600 dpi. Along with these parameters, the price of the scanner ranges from 80 to 100 thousand rubles.

Among the new products is a budget option. The Canon CanoScan 9000F scanner is a poor camera. Its resolution is 9600 × 9600 dpi. The price is 12 thousand rubles. Reviews about this model for the "four". The thing is that marketers are again starting their "song", telling about the unprecedented parameters. In fact, instead of 48 bits, we get only 12. That is, in each channel instead of 16 only 12 bits. Nevertheless, there are those who are satisfied with the speed of work, high resolution and quality of the materials of the device itself.

In general, to select a good scanner, scientists do not need to be, especially for ordinary users. For scanning documents and photocopies, large resolution is not required. Ultra-high speed is also not important. Therefore, it is better to choose the scanner that you really need in its full functionality.