How an optical scanner works?

Answer 1

Answer-- A device that can read text or illustrations printed on paper and translate the information into a form the computer can use. A scanner works by digitizing an image -- dividing it into a grid of boxes and representing each box with either a zero or a one, depending on whether the box is filled in. (For color and gray scaling, the same principle applies, but each box is then represented by up to 24 bits.) The resulting matrix of bits, called a bit map, can then be stored in a file, displayed on a screen, and manipulated by programs.

Optical scanners do not distinguish text from illustrations; they represent all images as bit maps. Therefore, you cannot directly edit text that has been scanned. To edit text read by an optical scanner, you need an optical character recognition (OCR ) system to translate the image into ASCII characters. Most optical scanners sold today come with OCR packages.

Scanners differ from one another in the following respects: # scanning technology: Most scanners use charge-coupled device (CCD) arrays, which consist of tightly packed rows of light receptors that can detect variations in light intensity and frequency. The quality of the CCD array is probably the single most important factor affecting the quality of the scanner. Industry-strength drum scanners use a different technology that relies on a photomultiplier tube (PMT), but this type of scanner is much more expensive than the more common CCD -based scanners. # resolution: The denser the bit map, the higher the resolution. Typically, scanners support resolutions of from 72 to 600 dpi. # bit depth: The number of bits used to represent each pixel. The greater the bit depth, the more colors or grayscales can be represented. For example, a 24-bit color scanner can represent 2 to the 24th power (16.7 million) colors. Note, however, that a large color range is useless if the CCD arrays are capable of detecting only a small number of distinct colors. # size and shape: Some scanners are small hand-held devices that you move across the paper. These hand-held scanners are often called half-page scanners because they can only scan 2 to 5 inches at a time. Hand-held scanners are adequate for small pictures and photos, but they are difficult to use if you need to scan an entire page of text or graphics.

Larger scanners include machines into which you can feed sheets of paper. These are called sheet-fed scanners. Sheet-fed scanners are excellent for loose sheets of paper, but they are unable to handle bound documents.

A second type of large scanner, called a flatbed scanner, is like a photocopy machine. It consists of a board on which you lay books, magazines, and other documents that you want to scan.

Answer 2

OCR (Optimal Character Recognition) or an Optimal Character Reader is the process is which a computer converts an image based on text into a editable format on a computer using a series of complex algorithms. A few examples of this would be Pixel based matching and Matrix Matching.

In a pixel based matching OCR algorithm the following steps are taken.

1.The image is first converted to black and white to remove noise and clutter.

2. The image is split into separate letters so each individual letter can be analysed.

3. It is usually compared against a set of stored letter then using this algorithm below.

For each letter in the stored set

Check how many black pixels there are on the image

Paste the split letter over the image (transparent)

Count how many pixels there are now

Match = (Pixels Before / Pixels After) * 100

Move onto next letter until a high match has been found then assign the output to the corresponding letter

Loop

This is a basic algorithm which works.

Answer 3

§OCR systems include an optical scanner for reading text, and sophisticated software for analyzing images. Most OCR systems use a combination of hardware (specialized circuit boards) and software to recognize characters, although some inexpensive systems do it entirely through software. Advanced OCR systems can read text in large variety of fonts, but they still have difficulty with handwritten text. The potential of OCR systems is enormous because they enable users to harness the power of computers to access printed documents. OCR is already being used widely in the legal profession, where searches that once required hours or days can now be accomplished in a few seconds.

Answer 4

With the OCR function, character recognition can be accomplished by just registering characters and specifying the area.

Both alphanumeric characters and user-defined characters can be identified.

The Auto calendar setting allows inspection of the date or lot numbers without the need for daily setting change.

Answer 5

It is a device which used to read an image & convert it into a set of zeroes & ones & stored in computer memory.