WEBVTT

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so it's 2:00 a.m. and you're laying alone on your coach watching reruns and

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suddenly your phone lights up with a message from a friend who needs a copy

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of a very important document that is sitting on your Cheeto dust covered

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coffee table for some reason so you go

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to take a picture of it with your phone but you realize your crappy built-in

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phone camera and the poor lighting from the dingy Bare Bulb hanging from the

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ceiling just aren't cutting it so decisively you dash to your PC and use

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your flatbed scanner and as you sit there listening to the whirling of the

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scanning mechanism and pondering how your life got to this point you find

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yourself asking how the heck do these things work

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anyways great question your typical scanner uses something called a charge

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coupled device or CCD to determine what's on the page the main idea here

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being that the CCD can convert light into an electrical charge which it then

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sends to your computer as Digital Data so when you start scanning a document

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that bright light that you see coming from inside typically from either a

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Xenon lamp or a cold cathode which as you may know is similar to what people

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used in PC case lighting a few years back hits the sheet of paper and was

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reflected back to a series of mirrors underneath the glass surface and then

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focused by a lens onto an array of CCD

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sensors since darker areas of the page containing things like text and clip art

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will reflect less light than the blank usually White areas the CCD array will

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see these differences which will show up as an accurate image of your document on

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your computer screen if you've ever had a scan of something bulky and had to

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leave the lid open a little bit you'll have noticed the scan is black in areas

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that aren't covered by anything this is because nothing's there to reflect the

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light though modern software is often smart enough to crop these areas out for

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you CCD arrays are also what determine a scanner's true resolution the more

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sensors in the array the more points of light it can capture and the more pixels

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it can send to your computer if you're in the market for a scanner make sure to

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check that the resolution on the spec sheet is the hardware resolution that

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reflects the true capabilities of the CCD array not some fake number achieved

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through software trickery like interpolation that uses average values

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of nearby pixels to approximate a higher

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pixel count image but what about color scanning this uses additional lenses and

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built-in color filters to separate the scan into red blue and green versions

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which are then processed to determine what the actual colors of your original

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document are although this is usually done with just one pass of the scanner

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some older models lack these additional lenses and so need multiple passes to

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complete a color scan which is why they were much slower in color mode but not

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every consumer level scanner works this way there are also flatbeds that use

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something called a contact image sensor or CIS instead of these ccds These are

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simpler in construction use an array of LEDs to shine light on the document so

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an image sensor can essentially take a snapshot of it like you were trying to

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do on the table with your cell phone but

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better although the scans from the CIS are typically lower quality than CCD

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scanners CIS is a cheaper more lightweight and more efficient

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technology so you'll find it in a lot of small port scanners that can be powered

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solely from a USB port instead of requiring a wall outlet of course there

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are other types of scanners out there such as expensive drum scanners with

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high dynamic range for professional applications as well as 3D scanners

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which you can learn more about right up here but hopefully this episode has

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given you a little insight into how your scanner at home works and let us know

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down in the comments down below if you'd like to see a future episode on what

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scanner to bu are you racing against the clock as a freelancer challenging yes

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and enter techwiki in the how did you hear about a section all right guys if

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you like this video like if you dislike to dislike it comment down below for

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other stuff that we should cover on this channel um follow this Channel with the

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Subscribe button hit the little bell there that lets you know every single

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time we get a new video also check out Channel Super Fun they're probably doing

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something hilarious over there they usually are and I'm going to roll out

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like a drum scanner