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in computing, a scanner is a device that analyzes an image (such as a photograph, printed text, or handwriting) or an object (such as an ornament) and converts it to a digital image. Most scanners today are variations of the desktop (or flatbed) scanner The flatbed scanner is the most common in offices. Hand-held scanners, where the device is moved by hand, were briefly popular but are now not used due to the difficulty of obtaining a high-quality image. Both these types of scanners use charge-coupled device (CCD) or Contact Image Sensor (CIS) as the image sensor, whereas older drum scanners use a photomultiplier tube as the image sensor.
Another category of scanner is a rotary scanner used for high-speed document scanning. This is another kind of drum scanner, but it uses a CCD array instead of a photomultiplier.
Other types of scanners are planetary scanners, which take photographs of books and documents, and 3D scanners, for producing three-dimensional models of objects.
Scanners typically read red-green-blue color (RGB) 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 SCSI or USB, or LPT in machines pre-dating the USB standard). Color depth varies depending on the scanning array characteristics, but is usually at least 24 bits. High quality models have 48 bits or more color depth. The other 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 2004, a good flatbed scanner has an optical resolution of 1600â3200 ppi, high-end flatbed scanners can scan up to 5400 ppi, and a good drum scanner has an optical resolution of 8000â14,000 ppi.
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. The higher the resolution, the larger the file. In most cases, there is a trade-off between manageable file size and level of detail. Resolutions higher than 1200dpi are overkill for colour printers and monitors.
The third important parameter for a scanner is its density range. A high density range means that the scanner is able to reproduce shadow details and brightness details in one scan.
in computing, a scanner is a device that analyzes an image (such as a photograph, printed text, or handwriting) or an object (such as an ornament) and converts it to a digital image. Most scanners today are variations of the desktop (or flatbed) scanner The flatbed scanner is the most common in offices. Hand-held scanners, where the device is moved by hand, were briefly popular but are now not used due to the difficulty of obtaining a high-quality image. Both these types of scanners use charge-coupled device (CCD) or Contact Image Sensor (CIS) as the image sensor, whereas older drum scanners use a photomultiplier tube as the image sensor.
Another category of scanner is a rotary scanner used for high-speed document scanning. This is another kind of drum scanner, but it uses a CCD array instead of a photomultiplier.
Other types of scanners are planetary scanners, which take photographs of books and documents, and 3D scanners, for producing three-dimensional models of objects.
Scanners typically read red-green-blue color (RGB) 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 SCSI or USB, or LPT in machines pre-dating the USB standard). Color depth varies depending on the scanning array characteristics, but is usually at least 24 bits. High quality models have 48 bits or more color depth. The other 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 2004, a good flatbed scanner has an optical resolution of 1600â3200 ppi, high-end flatbed scanners can scan up to 5400 ppi, and a good drum scanner has an optical resolution of 8000â14,000 ppi.
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. The higher the resolution, the larger the file. In most cases, there is a trade-off between manageable file size and level of detail. Resolutions higher than 1200dpi are overkill for colour printers and monitors.
The third important parameter for a scanner is its density range. A high density range means that the scanner is able to reproduce shadow details and brightness details in one scan.
Why all the hoopla over 3d printer guns?
Obama fail
What are the odds that normal folks have 2 - 50k to shell out for the machines that do this stuff. Just more hysteria from the media.
Latest example at nypost.com
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Oh, you mean the thought that for say $5,000-$10,000 a group of terrorists like the Arian Brotherhood could create an arsenal of untraceable guns that could pass right through airport scanners, is all right with you? Well, it is NOT alright with 90% of Americans.
I have worked with 3D printers and the current generation IS capable of creating weapons that are untraceable and undetectable by airport scanners. And once you understand the process and practice creating the raw materials to print with you can literally create ceramic guns and cartridges and bullets that can't be detected by airport scanners. So what if one out of ten crack in the kiln if you are creating 1,000 that still leaves 900 working firearms.
Oh, you mean the thought that for say $5,000-$10,000 a group of terrorists like the Arian Brotherhood could create an arsenal of untraceable guns that could pass right through airport scanners, is all right with you? Well, it is NOT alright with 90% of Americans.
I have worked with 3D printers and the current generation IS capable of creating weapons that are untraceable and undetectable by airport scanners. And once you understand the process and practice creating the raw materials to print with you can literally create ceramic guns and cartridges and bullets that can't be detected by airport scanners. So what if one out of ten crack in the kiln if you are creating 1,000 that still leaves 900 working firearms.
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Title Post: What is an optical scanner and how does it work?
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Author: Yukie
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Rating: 100% based on 99998 ratings. 5 user reviews.
Author: Yukie
Thanks For Coming To My Blog
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