Posts
gbeuchel
When it comes to scanners, what is the difference between:
CIS
CMOS
Note: I want to scan family photos
Answer
I'll list some pros and cons and leave it to you to decide.
CIS
pros: cheaper than CMOS, uses less current so some of them can operate entirely off the USB port and won't require an external adaptor meaning they could in theory be hooked up to a laptop and made portable.
cons: my personal impression is that the contrast ratio for CIS is inferior to cmos. Probably because the light used in CIS is different (weaker?) than cmos. But this is easily rectified if you purchase a good quality CIS scanner. CIS can't scan 3D objects.
CMOS:
pros: can scan a surface that isn't entirely flat (CIS only scans surfaces that are in contact with the scanner glass, anything further aware than several fractions of an inch just shows up as a blur). That makes CMOS good for scanning thick books as it will scan words that are printed near the spine and that can't be made to lay entirely flat unto the glass.
Cons: generally heavier than CIS. requires external power supply so not portable. Might be slightly more costly.
I'll list some pros and cons and leave it to you to decide.
CIS
pros: cheaper than CMOS, uses less current so some of them can operate entirely off the USB port and won't require an external adaptor meaning they could in theory be hooked up to a laptop and made portable.
cons: my personal impression is that the contrast ratio for CIS is inferior to cmos. Probably because the light used in CIS is different (weaker?) than cmos. But this is easily rectified if you purchase a good quality CIS scanner. CIS can't scan 3D objects.
CMOS:
pros: can scan a surface that isn't entirely flat (CIS only scans surfaces that are in contact with the scanner glass, anything further aware than several fractions of an inch just shows up as a blur). That makes CMOS good for scanning thick books as it will scan words that are printed near the spine and that can't be made to lay entirely flat unto the glass.
Cons: generally heavier than CIS. requires external power supply so not portable. Might be slightly more costly.
What is an optical scanner and how does it work?
huzaifai
Answer
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.
Powered by Yahoo! Answers
Title Post: What sensor is better? CIS or CMOS in scanners?
Rating: 100% based on 99998 ratings. 5 user reviews.
Author: Yukie
Thanks For Coming To My Blog
Rating: 100% based on 99998 ratings. 5 user reviews.
Author: Yukie
Thanks For Coming To My Blog
No comments:
Post a Comment