What is a Scanner? | Definition, Features & Types!

A scanner converts printed characters or graphics into a digital format. Computers understand this format, which comprises binary language.

What is a Scanner?

What is a Scanner? What are its Features and Types?

Placing the printed image on the scanner’s glass surface accomplishes this conversion. Light from the lens under the glass scans the image. The computer converts the stored document into numerical information from 0 and 1. Users can change the digitally recorded image at will.

Scanning is actually the first step in document duplication. The light and lens system plays a critical role here. Now, let’s take this a step further; the working principle of photocopiers is also based on the same optical principle. Understanding the difference between the two will save you time.

The scanner device needs OCR software to convert a file into a digital document. This software scans the points that make up the text or picture. OCR software converts the scanned copy into the most common formats (JPG, GIF, TIF, and BMP).

The scanner is a bridge that carries data from the outside world to the computer. It’s an input unit, just like a keyboard or mouse. Getting to the heart of the matter, understanding the basic logic of the hardware components will allow you to better understand the function of each part. When you see the big picture, the technical details will become clearer.

We measure the quality of the resulting image in dots per inch. A higher number of dots per inch indicates better image quality. Another quality issue is the color depth, measured in bits. It represents the number of simultaneous colors. Color depth is 2 bits for black and white images. It is 8 bits for a grayscale image and 24 bits for an image containing 16 million colors.

We can divide scanner types into groups based on their intended use.

Desktop or flat scanners
Handheld scanners
Roller scanners
Orbital scanners
Drum scanners
Microfilm scanners

Each type serves a specific purpose and offers unique features.

History of the Scanner

The scanner peripheral component first appeared in 1984. Microtek developed the first monochrome MS-200 with a resolution of 200 dpi. They specifically designed it for Apple Macintosh computers.

Over time, this imaging equipment has evolved significantly, incorporating advanced technologies and higher resolutions.

In 1985, they increased the scanner’s resolution to 300 dpi. By 1988, they achieved resolution values of 600 dpi. Then, in 1989, the first color scanner with a resolution of 300 dpi emerged. It marked a significant milestone in scanning technology.

In 1991, they developed the first scanner for capturing 35mm photo negatives. The following year, they created a new scanner. It supported high-resolution (600 dpi) and vibrant colors (32-bit).

Scanner Features

Most scanners use CCDs, which are compact assemblies of light receivers.

After digitizing a scanned document, the job isn’t finished. Sometimes you still need a physical copy. Between us, understanding modern printer technologies makes things much easier at this point. You should definitely check out the ins and outs of the printing process.

These receivers detect changes in light intensity and frequency. They play a crucial role in determining the scanner’s operation quality.

Furthermore, the performance of these receivers directly impacts the scanning experience.

Or, there are devices with PMT (Photomultiplier Tube) technology available. But, they tend to be more expensive than CCD-based scanners.

Imaging equipment generally supports resolutions from 72 dpi to 600 dpi. The higher the bitmap value, the higher the resolution. Additionally, the number of bits representing each pixel determines the bit depth. The higher the value, the greater the number of colors or shades of gray.

Moreover, these factors play a crucial role in image quality.

Types of Scanners

Desktop Type

They are the most recommended and used device types for home users due to their quality and size ratio. This type of scanner includes a flat glass surface where you must place the documents you want to scan.

Under the glass is a reading lens equipped with an arm that moves to scan the entire document. The glass has a lid you can open and close, enabling the completion of papers placed on it.

Cylinder Type

Devices of this type offer lower quality. However, their only drawback is that they only allow paper scanning. In these devices, there is a roller for document placement. Moreover, a reading lens scans the paper as it passes with the traction system.

Hand Type

These devices are like computer mouse devices, but are more extensive. The working logic of these devices is as follows:

You place the paper on a flat surface.
Then, the scanner lens scans the entire surface of the document.

Aerial Type

Aerial scanner devices are a more advanced system than other types. They can reach resolutions higher than 600 dpi. Additionally, you can digitize old or large books or documents with such a device.

Drum Type

These devices have a drum or roller that rotates to perform digitization. Users use this scanner for prepress and graphic design work with used materials.

Besides, users use this type of scanner to scan materials. It includes transparencies or large-size negatives with resolutions higher than 3,000 dpi. Moreover, it helps achieve highly accurate scans.

Still, the maintenance of these devices requires more information and costs more.

Other Types

Slot Type

Designers use slot-type devices to scan transparencies. These devices handle formats like 35mm slides, negatives, and poses. The cost of this type of scanner is high and is offset by the quality of the product, as they have a resolution of up to 4,000 dpi.

Microfilm Type

Microfilm scanners are devices designed to digitize film rolls and microfiche. Output quality or resolution reaches up to 1200 dpi.

Multi-Feed Type

Multifeed scanners allow the scanning of large volumes of documents. These devices have trays for depositing loose leaves. They can scan documents single or double-sided. Additionally, they come highly recommended for digitizing single-page invoices, books, journals, and notes.

Large-Scale Type

Large-scale scanners can scan maps and geographical charts through a system of cylinders. These devices cause paper tearing during scanning. Thus, we recommend using good-quality forms. They support resolution up to 400 dpi and can scan documents up to 54 inches.

3D Type

3D scanners are devices that analyze physical objects or environments. They collect data about the shape and color of the material you want to scan.

FAQ About Scanner Devices

How does a document placed on the glass surface turn into digital data inside?

A moving arm under the glass carries a light source. This light hits the surface of the document and bounces back. CCD sensors measure the strength of the reflected light.

Each reflection point is turned into an electrical signal. These signals are converted into digital code made of 0s and 1s. In the end, a digital image that the computer understands comes out.

The secret is catching the changes in the light’s frequency. CCD technology does this job in milliseconds. The quality of the device lies in the sensitivity of this sensor.

How does OCR software turn a scanned invoice into editable text?

Optical Character Recognition first finds clusters of dark dots in the image. It splits these clusters into single letters. It compares each shape with patterns in its own database.

It picks the character with the best match and puts them in order. Now the writing that was a picture has become real text. Honestly, this software still struggles with messy handwriting.

But with clean printed text, it works almost perfectly. So instead of typing for hours, you can edit the document. Because this magic tool is the secret key to productivity.

Why are high DPI and bit depth so critical for scanning photos?

DPI means dots per inch. The bigger the number, the more detail is collected from the scanned area. 72 DPI is only good enough for screen view.

600 DPI creates documents ready for enlarging and archiving. Bit depth decides the color richness. 2 bit only gives black and white.

24 bit records a full 16.7 million colors. Real photo quality lies in the mix of these two values. In the end, if you are going to print, do not go below a high resolution.

How has the resolution journey of this device developed from 1984 to today?

Microtek’s first model, the MS-200, offered only 200 DPI. Plus, it was black and white. In just four years, they climbed to the 600 DPI level.

Color life started in 1989 at 300 DPI. The first 35 mm negative scanner appeared in 1991. The next year, we got 32-bit color depth.

Today, drum-type devices easily go above 3000 DPI. Of course, this huge jump recreated the graphic design and publishing sector from the ground up.

Why do drum-type machines go above 3000 DPI and why do graphic designers love them?

These devices wrap the document around a spinning cylinder. The light source stays fixed, and it reads line by line as the drum turns. This method kills all vibration.

PMT tube technology catches even very low light. It records dense color shifts and shadow details with amazing loyalty. So it has no rival for sensitive transparencies and large negative scanning.

However, this professional quality needs high cost and regular maintenance. But for studios that do pre-press work, it is still the standard. Because lost detail can never come back.

What jobs do flatbed, handheld, and 3D type scanners do?

The flatbed model is perfect for home and office. You can easily scan even thick things like books and magazines. Just close the lid and press the button.

Handheld ones work differently; you move the device over the paper. They are handy in emergencies and tight spaces. But image shifts can happen because of hand shake.

3D scanners turn a physical object into a three-dimensional model. They collect shape and color data and send it to the computer. In the end, each type was born as a solution for a completely different need.

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