This is the main unit of the scanner that is responsible for the scanning process. The Photoelectric device is often referred to as the scanner.

It converts the scanned image into an electronic signal and this electronic signal is converted back into an electronic image, which can be seen on the display (monitor screen) through appropriate software. Scanners available in India are Flatbed and Sheetfeed.

A CCD scanner is more durable, and most importantly-provides better looking scans. However CIS scanners can be smaller, use less power, and cost less to manufacture.

It is the type of light source used in the photoelectric device like scanner.

There are two different light sources that are generally used and these depend on the photoelectric device. A CCD Scanner used a white cold cathode fluorescent lamp as its light source, and a CIS Scanner uses a three colour LED. Most scanners available in India are fitted with a CCD.

The maximum horizontal resolution of a scanner is governed by the number of elements in the scan line and the maximum width of the original. It is usually measured by DPI (dot per inch). The resolution in vertical and horizontal directions can be different.

The max horizontal resolution vary from scanner to scanner and range from 1200 to 19,200 dpi. You should choose the dpi best suited to the purpose you have for scanning as opting for a scanner having a higher dpi could mean greater expense.

The higher the resolution, the higher the volume of data to be processed.

The maximum Vertical resolution gives the maximum dpi a scanners software can scan vertically. The maximum vertical resolution of a scanner is governed by the step size of the scan head. It is usually given in DPI. The resolution in vertical and horizontal directions can be different.

The max vertical resolution vary from scanner to scanner and from dpi to dpi. You should choose the dpi best suited to the purpose you have for scanning as opting for a scanner having a higher dpi could mean greater expense.

The higher the resolution, the higher the volume of data to be processed.

The maximum number of different colours each pixel can display in an image, often measured in number of bits.

The greater the bit depth, more colours, shades, tones or grayscales can be represented. For example, a pixel defined using one bit of data could be black or white. Two bits of information could define four tones - black, dark grey, light grey, and white. Similarly an 8-bit scanner could capture 256 colours or tones and a 24-bit colour scanner can represent 16.7 million colours. Most computers can actually display only a 24-bit depth (16.7 million colours).

The greater the bit depth, more colours, shades, tones or grayscales can be represented. If you are into web designing, DTP publishing, and so on, you may need a very good scan quality say a 36-bit or a 42-bit scanner.

It is a pixel defining two bits of information namely four tones or a two level (bi-level) bit image.

These in binary terms will be 11 (black), 10 (dark grey), 01 (light grey) and 00 (white).

The scanner software helps to make-up for errors in the image scanned by taking the mean values of surrounding pixels and diffusing it onto the part having errors.

For example, if you scan a picture of nature, where the shades are many, you get a smooth image (in spite of blemishes in the picture scanned) using this feature, and yet maintain the contrasting colours and shades.

You get a smooth image (in spite of blemishes in the picture scanned) using this feature, and yet maintain the contrasting colours and shades.

Dithering is a process of specifying colour to adjacent pixels in order to simulate a third colour in a bitmapped image.

This technique is used when a full range of colours are not available.

This could be used for portraits where you can get a clear complexion of the scanned image.

Text Enhanced Technology can add value to your scanner by making it possible to scan in pages of printed material and convert it to editable text.

Text Enhanced Technology is quite similar to OCR, but is more advanced and better in scanning text. The difference being that the text enhanced technology has a software that is able to identify many more scripts and alphabet fonts and styles.

It saves you the trouble of re-typing documents. Just scan it using this feature and convert the document into editable text.

It is the process of adjusting an image to compensate for scanner deficiencies.

This is a function that is performed by the scanner software. It allows you to correct the colour of the scanned image.

The scanner software gives you a better quality image inspite of the scanner not being good enough.

An optical character recognition (OCR) utility can add value to your scanner by making it possible to scan in pages of printed material and convert it to editable text.

It is similar to Text Enhanced Technology but is not able to identify certain types of text and styles, which the more advanced Text Enhanced Technology can. While OCR programs often produce less than excellent results from faxes or magazine pages, they certainly eliminate the need to retype many documents -particularly business letters and other fairly plain printed pages. The most convenient kind of OCR software automatically pastes its OCRed results directly into your word processor or other application.

It saves you the trouble of re-typing documents. Just scan it using this feature and convert the document into editable text.

Automatic Document Feeder is a feature where the paper is automatically taken by the rollers and fed into the scanner for scanning.

The documents can be automatically fed into the scanner thus reducing manual effort. In a scanner, paper can be fed either manually or automatically. This eliminates the need to manually feed the paper. Generally about 30 sheets can be put into the scanner and can be scanned one at a time, all feeding of the paper is done automatically. Few flatbed scanners have this feature.

It saves you time.

3D scanning is the fast and accurate process of using a 3D scanner to capture and convert physical objects into digital 3D data.

3D scanners come in many flavors, but the purpose of every one of them is to capture the shape, and sometimes color, of real-world physical objects or environments.The captured data is typically stored as a list of xyz-coordinates in a point cloud file. 3D scanners can be categorized as contact (CMM arms) or non-contact (white light or 3D laser scanners). Some can even capture internal features.

An optical input system for digitizing images from small format positive or negative transparency film.

An add-on device used with a scanner to scan slides and other see-through media.