What is Scanner?

A scanner is an electrical device can read and translate text, images, and other materials into a digital signal. This transforms the documents into a format that computer software programs can use to view and/or edit them. There are many different types of scanners with various resolutions on the market.

What is a Scanner?

A Scanner is an electronic device that is used to read and convert documents such as photographs, magazines, posters, and images into digital copies for display, editing, and archiving. The digital copies can be further modified by using different software tools. Most scanners are connected to computers using cords that plug into a port that is readily accessible. Some modern scanners also come equipped with Bluetooth and wireless features which offer greater accessibility and flexibility. Scanners work in conjunction with software applications. By installing scanning plug-ins, the images can be directly imported into the software applications. For example, by installing a plug-in for Adobe Photoshop the users can create new images directly from the linked scanner.

History of Scanner

Modern scanners are considered evolutions of early telephotography and fax input devices. The pantelegraphy was the first device to be used commercially in the 1860s. It had the capacity to transmit handwriting, signatures, or drawings within an area of up to 150 × 100 mm.

The first scanner developed for use with a computer as we know it today was created by a team led by Russell A. Kirsch at the United States National Bureau of Standards in 1957. The first image ever scanned was a picture of Kirsch's son which was 5x5 cm in measurement and had a resolution of 176 x 176 pixels.

How Does a Scanner Work?

Different versions from different companies may have slight variations in the working and design but the core principle remains the same among all the scanners.

The document is placed on the scanner and the lid is closed after which a light source is used to illuminate the document from below. A scan head which comprises of mirror, lens, filter and CCD (Charge-coupled device) array is then moved across the document with the help of a belt and a stepper motor. A stabilizer is used to keep the scan head stable. A pass means that the scan head has completed one complete scan of the entire document. The image of the document is then reflected by an angled mirror on another secondary mirror. Secondary mirror reflects the image onto a lens. The lens focuses the image on the CCD array through a filter. The arrangement of the lens and CCD array may differ from scanner to scanner. Most scanners utilize a three pass method where different color filters (red, green or blue) are used between the lens and CCD array to generate the image. After all the three passes are complete the software assembles all the three filtered images into a single full-color image.

Types of Scanner

There are several types of Scanner that are mentioned below.

Drum Scanner

The drum scanner rotates scanned page around a drum for faster scanning. It scans with a photomultiplier tube rather than a charge-coupled device which is used in flatbed scanners. The drum scanners use photomultiplier tubes which are excessively sensitive to light. The image is mounted on the glass tube available in the scanner and when the scanning start the light is moved on top of the image while the photomultiplier tubes (PMT) pick up its reflection and process it. Drum scanners are generally known for their high resolution.

Flatbed Scanner

It is the most commonly used type of optical scanner which is readily available in the market. The documents are placed on a flat surface by lifting the cover and then the lid is closed after placing the documents. It is easy to operate and user friendly. It can be used to scan a wide variety of documents such as books, magazines and images. Some flatbed scanners also come equipped with Bluetooth or wireless technologies as well as automatic feeders which makes the process easy and simple.

Sheetfed Scanner

The main characteristic of a sheetfed scanner is that they are specifically designed to handle loose sheets of paper. These scanners are great in scanning enormous amount of paper sheets. They are generally a little smaller than flatbed scanners and feature a lesser image resolution. They are mainly used by business and offices who have a limited amount of space. Sheetfed scanners are fast in terms of paperweight and size (pages per minute). They are equipped with a feeder tray which automatically feeds into the scanner.

Handheld Scanner

It is a portable handheld device that works similarly to a flatbed scanner. Instead of inserting the document as its is done in flatbed, here, the scanner is dragged over the document to be scanned. Handheld scanners are preferred over flatbed scanner as they are very compact, easy to use and offer greater flexibility . They are mainly used in shopping stores and storage houses to evaluate goods by scanning barcodes.

Uses of Scanner

• Copying: Scanners can be used to make multiple copies of a physical document such as flyers or posters.
• Archiving: One of the popular uses of scanners is for archiving. Physical documents can be scanned and stored digitally for preservation.
• Sharing Photos: Photos taken from old and traditional film cameras can be scanned to share digitally with friends and family over the internet.
• Research: Scanners are also useful for research purposes. Relevant documents can be scanned for referencing later when required.
• Portability: Portable scanners provide flexibility as they are small and easy to carry. Portable scanners are very good at digitizing documents, scanning images and making PDFs.

Advantages of Scanner

• Cost Effective: A scanner helps in saving cost as it transforms physical documents into digital ones that helps in saving space.
• Reliability: Digitally scanned documents are safe from physical corrosion caused due to environmental factors such as humidity. Thus digitally scanned documents can be preserved in original format over a long period of time.
• Ease of Use: Modern scanners are equipped with user friendly interface which makes them easy to operate. Most of the functions are automatically adjusted for simple operations. Most modern scanners also come equipped with wireless technologies such as bluetooth making them more accessible.
• High Quality: They can replicate physical documents with a high degree of accuracy and resolution.
• Efficiency: Large quantities of documents can be scanned through with quicker speed and higher resolution due to faster operations provided by modern scanners.
• Environment friendly: Less use of paper for documenting leads less wastage and healthy environmental impacts.

Disadvantages of Scanner

• Maintenance: Maintenance for some scanners can be costly which adds to overall cost of operations.
• Limited Functionality: Although scanners are quite versatile, they still offer only limited functionality as compared to cameras and phones which can also be used for taking videos.
• Security Concerns: Sensitive documents such as personnel information or financial records can be subject to compromise due to lack of security layers. This may require using encryption to prevent unauthorized access.
• Quality Control: The quality of the digital document depends upon the quality of the scanner and the settings used. This can lead to issues such as blurriness, distortion, or color inaccuracies.
• Physical Incompatibility: Scanning deformed documents such as curved or folded pages can lead to inaccurate scanning and distorted output.