The purpose of hand-held scanner

In computing, a scanner is a Input device that analyzes & captures an image (such as a photograph, printed text, or handwriting) or an object (such as an ornament) from the source documents into the Computer system and converts it to a digital image. Scanner facilitates the capturing information in graphical as well in editable format. The graphical images thus scanned can be seen and processed directly by the computer.

Two types of scanner are CONTACT and LASER. Most scanners today are variations of the desktop (or flatbed) scanner. The flatbed scanner is the most common in offices.
Hand-held scanner is the laser scanner, where the device is moved by hand. The main purpose of using hand-held scanner is for quickly capturing text.
Hand-held scanner is that, which moves across the image to be scanned by hand. They are small and less expensive than their desktop counterparts, but rely on the dexterity of the user to move the unit across the paper. Trays are available that keep the scanner moving in a straight line.

Handheld scanners are a convenient way to get printed text into an editable format on your computer, but the best devices are prohibitively expensive.

Hand scanners are manual devices, which are dragged across the surface of the image to be scanned. Scanning documents in this manner requires a steady hand, as an uneven scanning rate would produce distorted images. They typically have a "start" button which is held by the user for the duration of the scan, some switches to set the optical resolution, and a roller which generates a clock pulse for synchronization with the computer. A typical hand scanner also had a small window through which the document being scanned could be viewed.

Handheld scanners have scan heads 4-5 inches wide, which makes them very portable. They plug into parallel port so they're easy to share among people and can be a good addition to laptop.

You can get cheap handheld scanners for under $150, but their declining popularity might make them hard to find. Another kind of handheld scanner is the pen scanner. You drag a pen scanner over a line of print like a highlighter. The built-in optical recognition software turns the scan into text, which can be transferred in to a computer via serial or USB port. Handheld Barcode scanners are also well known & in use for reading barcode of the items in a most of the shopping centers.

In case of some advanced Hand-held scanners for e.g Wizcom Handheld scanner, the device can "see" text and automatically activate the scanner when text comes into its field of view. Then, you only have to roll the pen smoothly over the line you want to capture and lift it off the page at the end of the text line. The optical character recognition (OCR) engine then translates the scanned images into editable text.

Handheld scanners use the same basic technology as a flatbed scanner, but rely on the user to move them instead of a motorized belt. It is briefly popular but is now not used due to the difficulty of obtaining a high-quality image.