Flatbed Input DevicesFlatbed devices use a surface as an input surface. You just need to place the document on a surface to scan.Scanners can be of two types:Flatbed Scanner Hand-Held ScannersFlatbed ScannerFlatbed scanners use a lid and a glass surface below which the sensor lies. Sensor may or may not have moving parts. There can be two types of sensorsCCDCISWorking:A flatbed scanner sees images and converts them into electronic codes. The scanning unit moves over the image.Reads the image as series of dots and digitizes it.This is then sent to the computer and stored as a file.Advantages:The noise level is low.It is highly reliable.It is very easy to scan.Doesn’t require any previous knowledge to  be able to use it.Light distortion is less.You do not require to move the document.Doesn’t damage the document.DisadvantagesIf it uses a LED lamp then the noise levels are very high.It is bulky and thus isn’t very commercial.Handheld ScannerThese are handheld scanners which require you to move the sensor over the document to be able to scan it. This the biggest disadvantage of using a handheld scanner. This is why has a very few applications. Most of the handheld scanners are used to scan barcodes.Advantages:It is portable which adds to the usability of it.The noise level is low.It is highly reliable.It is very easy to scan.Doesn’t require any previous knowledge to  be able to use it.Light distortion is less.DisadvantagesYou require to move your hand over the document.You need to have a stable hand.If it uses a LED lamp then the noise levels are very high.It is bulky and thus isn’t very commercial.Smartphone ScannersDue to immense advancement in technology in the last decade smartphones have evolved and now provide with several features making several technologies absolute. Scanner is also going that route, with digitalization number of people owning a smartphone has gradually increased.Smartphones these days have a pretty good camera. This camera other than taking pictures and videos can serve several other purposes. Scanning on smartphone has never been easy, you just require to take a picture and application converts it to a scanned document. A lot of applications have been built around this technology. You can also get OCR(Optical Character Recognition) at the palm of your hand, it extracts the text from the scanned document.Examples: CamScanner, Pic Scanner.