Digital Scanners - The Scanning Process, Color Scanning, Digital Scanners For Publishing, Scanners That Can Read
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A scanner is a computer accessory (peripheral) used to digitize pictures.
A scanner converts a visual image to a digital signal. The signal is interpretable by computer software, which allows the image to be recorded, manipulated, and even sent electronically to another computer.
Even in the early 1990s, computers were used more for "in house" functions, such as preparing documents. But, with the expanding power of the Internet and the development of powerful and sophisticated software, computers became important for the preparation and publication of professional quality documents that included graphics.
One means by which photographs can be efficiently transferred from one computer to another is by scanning the image and digitizing the information as a computer file.
In the recording of music, compact discs convert the spectrum of instrumental or vocal sound into the 1s and 0s of digital code. Scanners perform an analogous function for images. A digital scanner converts the continuous tones in a photograph (light) into the digital code that is the language understood by computers. All words, numbers, images, and instructions to the computer ultimately consist of series of ones and zeroes.
Digital scanners can use laser light to scan an image. These scanners, while offering superb quality, are so expensive as to be beyond most budgets. The scanners that use conventional visible light are more affordable and, hence, far more popular.
Additional Topics
A scanner initially operates much like a photocopier. An image such as a photograph or a drawing is placed on a transparent plate. The lid of the scanner is closed to keep stray outside light from entering. When the scan is begun, an incandescent or fluorescent light illuminates the image on the transparent plate. The light that reflects off of the image enters a lens. At this point the scanner op…
Depending on the configuration of the machine, a scanner can produce images that are black and white or color. In a color scanner the digital color image consists of three gray-scale images. These images are often called layers. One layer defines which areas will be green in the final color image. The other two layers do the same for red and blue. To create the differently colored layers, the scan…
High-end (technically complex and expensive) digital scanners are typically used where a professional quality image is necessary, such as in magazine publishing. These scanners often use lasers to read the original images. The image is placed in a transparent drum, which rotates past the laser. The document is scanned in a precise pattern, and is scanned in great detail (i.e., one pixel at a time)…
Scanning artwork and photographs for reproduction is only one reason to use a digital scanner. Another important use is to enable computers to read printed documents. This process is called optical character recognition. In optical character recognition, a black-and-white digital scan is first made of a document. Using various software programs, a computer is able to recognize this image as variou…
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