Scannning Process

1.0 Introduction

A scanner is a device that captures images from photographic prints, posters, magazine pages, and similar sources for computer editing and display. Scanners come in hand-held, feed-in, and flatbed types and for scanning black-and-white only, or color. Very high resolution scanners are used for scanning for high-resolution printing, but lower resolution scanners are adequate for capturing images for computer display. Scanners usually come with software, such as Adobe's Photoshop product, that lets you resize and otherwise modify a captured image. Scanners usually attach to your personal computer with a Small Computer System Interface (SCSI). An application such as Photoshop uses the TWAIN program to read in the image. Some major manufacturers of scanners include: Epson, Hewlett-Packard, Microtek, and Relisys. (Margaret Rouse, 2018)     

According to Online Dictionary Scanning means look at all parts of (something) carefully in order to detect some feature. In other word Scanning is reading a text quickly in order to find specific information, e.g. figures or names. (TeachingEnglish.org.uk, 2018)

1.1 Aim

·         The aim of this work is to figure out the procedures of document scanning

1.2 Objectives

·         The objective of this research is to outline the procedures of scanning process and how does it scanner work

2.0 Review Related Literature

Modern scanners are considered the successors of early telephotography and fax input devices. The pantelegraph (Italian: pantelegrafo; French: pantélégraphe) was an early form of facsimile machine transmitting over normal telegraph lines developed by Giovanni Caselli, used commercially in the 1860s, that was the first such device to enter practical service. It used electromagnets to drive and synchronize movement of pendulums at the source and the distant location, to scan and reproduce images. It could transmit handwriting, signatures, or drawings within an area of up to 150 x 100mm.

Édouard Belin's Belinograph of 1913, scanned using a photocell and transmitted over ordinary phone lines, formed the basis for the AT&T Wirephoto service. In Europe, services similar to a wirephoto were called a Belino. It was used by news agencies from the 1920s to the mid-1990s, and consisted of a rotating drum with a single photodetector at a standard speed of 60 or 120 rpm (later models up to 240 rpm). They send a linear analog AM signal through standard telephone voice lines to receptors, which synchronously print the proportional intensity on special paper. Color photos were sent as three separated RGB filtered images consecutively, but only for special events due to transmission costs. (Wikipedia, 2018)

An image scanner—often abbreviated to just scanner, although the term is ambiguous out of context (barcode scanner, CT scanner etc.) is a device that optically scans images, printed text, handwriting or an object and converts it to a digital image. Commonly used in offices are variations of the desktop flatbed scanner where the document is placed on a glass window for scanning. Hand-held scanners, where the device is moved by hand, have evolved from text scanning "wands" to 3D scanners used for industrial design, reverse engineering, test and measurement, orthotics, gaming and other applications. Mechanically driven scanners that move the document are typically used for large-format documents, where a flatbed design would be impractical.

Modern scanners typically use a charge-coupled device (CCD) or a contact image sensor (CIS) as the image sensor, whereas drum scanners, developed earlier and still used for the highest possible image quality, use a photomultiplier tube (PMT) as the image sensor. A rotary scanner, used for high-speed document scanning, is a type of drum scanner that uses a CCD array instead of a photomultiplier. Non-contact planetary scanners essentially photograph delicate books and documents. All these scanners produce two-dimensional images of subjects that are usually flat, but sometimes solid; 3D scanners produce information on the three-dimensional structure of solid objects.

Digital cameras can be used for the same purposes as dedicated scanners. When compared to a true scanner, a camera image is subject to a degree of distortion, reflections, shadows, low contrast, and blur due to camera shake (reduced in cameras with image stabilization). Resolution is sufficient for less demanding applications. Digital cameras offer advantages of speed, portability and non-contact digitizing of thick documents without damaging the book spine. As of 2010 scanning technologies were combining 3D scanners with digital cameras to create full-color, photo-realistic 3D models of objects. (Wikipedia, 2018)

In the biomedical research area, detection devices for DNA microarrays are called scanners as well. These scanners are high-resolution systems (up to 1 µm/ pixel), similar to microscopes. The detection is done via CCD or a photomultiplier tube.

2.1 How does it scanner Work

Scanners have become an important part of the home office over the last few years. Scanner technology is everywhere and used in many ways:

• Flatbed scanners, also called desktop scanners, are the most versatile and commonly used scanners. In fact, this article will focus on the technology as it relates to flatbed scanners.
• Sheet-fed scanners are similar to flatbed scanners except the document is moved and the scan head is immobile. A sheet-fed scanner looks a lot like a small portable printer.
• Handheld scanners use the same basic technology as a flatbed scanner, but rely on the user to move them instead of a motorized belt. This type of scanner typically does not provide good image quality. However, it can be useful for quickly capturing text.
• Drum scanners are used by the publishing industry to capture incredibly detailed images. They use a technology called a photomultiplier tube (PMT). In PMT, the document to be scanned is mounted on a glass cylinder. At the center of the cylinder is a sensor that splits light bounced from the document into three beams. Each beam is sent through a color filter into a photomultiplier tube where the light is changed into an electrical signal.

The basic principle of a scanner is to analyze an image and process it in some way. Image and text capture (optical character recognition or OCR) allow you to save information to a file on your computer. You can then alter or enhance the image, print it out or use it on your Web page. (Jeff Tyson, 2018)

2.2 What does it mean to scan a document?

Present on a variety of business and office printers, scanning is a function that digitizes printed documents and pictures and sends the files to your computer or outputs a duplicate copy of the items via the printer. Printers that contain built-in scan components include all-in-one, inkjet and laser printers. (Nick Davis, 2018)

2.3 Types of Document Scanning

PDF (Portable Document Format): A PDF file is among the most commonly used file types. This file type is great for documents with text, forms, and images that contain words. Certain programs use OCR technology to make the characters in the document searchable and editable. PDFs can even be used for images since they include automatic image compression.

JPG or JPEG (Joint Photographic Experts Group): JPEGs are great for images because they can compress very large files down to a small size. This is achieved by using what’s called lossy compression, a process that extracts some of a file’s data in order to decrease the storage demand. Because lossy compression removes data from the original file, lines can show up poorly (such as logos and other graphics with lines) so it’s best to use JPEGs for files without those attributes.

PNG (Portable Network Graphics): PNG files were actually created as a workaround for GIF files, which were owned by a company that charged licensing fees for usage. PNG files are mostly for digital image files and they utilize document compression, but not as much as JPEGs do. But, if you’re scanning a document with text in it or lines then PNGs can be good because they’re considered “lossless”, meaning they will produce a less pixelated file.

TIF or TIFF (Tagged Image File Format): TIFs are great for files that you don’t want compressed, because you want every bit of the data in your document. Because of this, TIF files tend to be very large, but they will hold much more detail than other file types. With the larger file size, you also get more flexibility when it comes to color and content. Colors can be grayscale, printable CMYK and even RGB for the internet. Your content can also be stored with layers and tags intact. (Ilmcorp.com 2015)

2.4 Types of Scanners

The four common scanner types are: Flatbed, Sheet-fed, Handheld, and Drum scanners.

Flatbed Scanners: Flatbed scanners are some of the most commonly used scanners as it has both home and office functions. The way they scan documents is that a mechanism rolls under the document to obtain the image. For businesses that have a need for high processing abilities, the flatbed scanner can scan any number of documents with a click of a button. (Wikibooks, 2018)

Figure 1: Flatbed Scanner

Sheet-Fed Scanners: Sheet-fed scanners cost between $300 and $800. This type of scanner works like a flatbed scanner except that the image is fed through the scanner and moves along the beam to be read rather than the beam moving. This type is not useful for books, but only single sheets. (Wikibooks, 2018)

Figure 2: Sheet-Fed Scanners

The aforementioned scanner types are the most common types of scanners used in homes and small offices.

Integrated Scanners: Integrated scanners are becoming one of the most modern types of scanners when it comes to obtaining images. ATMs feature this type of built-in scanner for check-processing and approval. (Wikibooks, 2018)

Figure 3: Integrated Scanners

Drum Scanners: These types of scanners are used mainly for capturing a picture and producing at a very high resolution rate. There are only a few companies that make these scanners, considering the high cost of producing a scanner such as this. It is considered a tremendous upgrade to a regular flatbed scanner. (Wikibooks, 2018)

Figure 4: Drum Scanner

Portable Scanners: Portable scanners are designed to capture text and other data while you are on the go. The scanner is powered by batteries and once you scan the text, the content is stored on the portable scanner. Once you get home, you can transfer the content to a computer. Transferring to your computer is done by using a cable or a wireless connection. (Wikibooks, 2018)

Figure 5: Portable Scanners

Scan quality

Color scanners typically read RGB (red-green-blue color) data from the array. This data is then processed with some proprietary algorithm to correct for different exposure conditions, and sent to the computer via the device's input/output interface (usually USB, previous to which was SCSI or bidirectional parallel port in older units).

Color depth varies depending on the scanning array characteristics, but is usually at least 24 bits. High quality models have 36-48 bits of color depth.

Another qualifying parameter for a scanner is its resolution, measured in pixels per inch (ppi), sometimes more accurately referred to as Samples per inch (spi). Instead of using the scanner's true optical resolution, the only meaningful parameter, manufacturers like to refer to the interpolated resolution, which is much higher thanks to software interpolation. As of 2009, a high-end flatbed scanner can scan up to 5400 ppi and drum scanners have an optical resolution of between 3,000 and 24,000 ppi.

"Effective resolution" is the true resolution of a scanner, and is determined by using a resolution test chart. The effective resolution of most all consumer flatbed scanners is considerably lower than the manufactures' given optical resolution. Example is the Epson V750 Pro with an optical resolution given by manufacturer as being 4800dpi and 6400dpi (dual lens), (Wikipedia 2018) but tested "According to this we get a resolution of only about 2300 dpi - that's just 40% of the claimed resolution!(Wikipedia, 2018) “Dynamic range is claimed to be 4.0 Dmax, but "Regarding the density range of the Epson Perfection V750 Pro, which is indicated as 4.0, one must say that here it doesn't reach the high-quality [of] film scanners either." (Wikipedia, 2018)  

Manufacturers often claim interpolated resolutions as high as 19,200 ppi; but such numbers carry little meaningful value, because the number of possible interpolated pixels is unlimited and doing so does not increase the level of captured detail.

The size of the file created increases with the square of the resolution; doubling the resolution quadruples the file size. A resolution must be chosen that is within the capabilities of the equipment, preserves sufficient detail, and does not produce a file of excessive size. The file size can be reduced for a given resolution by using "lossy" compression methods such as JPEG, at some cost in quality. If the best possible quality is required lossless compression should be used; reduced-quality files of smaller size can be produced from such an image when required (e.g., image designed to be printed on a full page, and a much smaller file to be displayed as part of a fast-loading web page).

Purity can be diminished by scanner noise, optical flare, poor analog to digital conversion, scratches, dust, Newton's rings, out of focus sensors, improper scanner operation, and poor software. Drum scanners are said to produce the purest digital representations of the film, followed by high end film scanners that use the larger Kodak Tri-Linear sensors.

The third important parameter for a scanner is its density range (Dynamic Range) or Drange (see Densitometry). A high density range means that the scanner is able to record shadow details and brightness details in one scan. Density of film is measured on a base 10 log scale and varies between 0.0 (transparent) and 5.0, about 16 stops. (Wikipedia, 2018) Density range is the space taken up in the 0 to 5 scale, and Dmin and Dmax denote where the least dense and most dense measurements on a negative or positive film. The density range of negative film is up to 3.6d, (Wikipedia, 2018) while slide film dynamic range is 2.4d.(Wikipedia, 2018) Color negative density range after processing is 2.0d thanks to compression of the 12 stops into a small density range. Dmax will be the densest on slide film for shadows, and densest on negative film for highlights. Some slide films can have a Dmax close to 4.0d with proper exposure, and so can black-and-white negative film.

Consumer-level flatbed photo scanners have a dynamic range in the 2.0–3.0 range, which can be inadequate for scanning all types of photographic film, as Dmax can be and often is between 3.0d and 4.0d with traditional black-and-white film. Color film compresses its 12 stops of a possible 16 stops (film latitude) into just 2.0d of space via the process of dye coupling and removal of all silver from the emulsion. Kodak Vision 3 has 18 stops. So, color negative film scans the easiest of all film types on the widest range of scanners. Because traditional black-and-white film retains the image creating silver after processing, density range can be almost twice that of color film. This makes scanning traditional black-and-white film more difficult and requires a scanner with at least a 3.6d dynamic range, but also a Dmax between 4.0d to 5.0d. High-end (photo lab) flatbed scanners can reach a dynamic range of 3.7, and Dmax around 4.0d. Dedicated film scanners (Wikipedia, 2018) have a dynamic range between 3.0d–4.0d. (Wikipedia, 2018) Office document scanners can have a dynamic range of less than 2.0d. (Wikipedia, 2018) Drum scanners have a dynamic range of 3.6–4.5.

By combining full-color imagery with 3D models, modern hand-held scanners are able to completely reproduce objects electronically. The addition of 3D color printers enables accurate miniaturization of these objects, with applications across many industries and professions.

For scanner apps, the scan quality is highly dependent on the quality of the phone camera and on the framing chosen by the user of the app. (Wikipedia, 2018)

3.0 Methodology

The method involved internet review based on search engines and investigation on Scanning Process.

3.1 Scanning Process

The Windows Fax and Scan utility enables you to scan documents and pictures. Before you can scan documents and pictures, you must have a scanner installed on your computer. Your scanner must be listed in the Devices section of the Devices and Printers Control Panel window.

Remember to check to see if your scanner is properly installed, open the Device Stage. Choose Start→Devices and Printers. If Windows doesn’t automatically find your scanner, you can manually add it in the Devices and Printers window by clicking the Add a Device button in the toolbar and following the wizard’s commands.

1. Choose Start→All Programs→Windows Fax and Scan.
2. Click the Scan button in the Navigation pane, then click the New Scan button on the toolbar.
3. Use the settings on the right to describe your scan.
4. Click the Preview button to see what your document will look like.
5. If you're happy with the preview, click the Scan button.

6.      Click the Save As button and complete the necessary information. Enter the filename, the type of graphics file you want saved, and then click the Save button. (Greg Harvey, 2018)

To automatically forward the document you’ve just scanned as an attachment to a new fax message, click the Forward as Fax button.

Remember: The scan feature in the Windows Fax and Scan utility is set primarily to scan text documents. If you want to scan a photograph or other graphic, you’re better off doing that directly within the Windows Live Photo Gallery.