Flatbed Scanners
Scanner are divided into following categories such as
Flatbed scanners
Sheet-fed-scanners
Handheld scanners
Drum scanners
Portable scanners
Production scanners and
Bar code laser scanners
Scanners Definition
The scanner is nothing but a device which captures (scan) images , texts , three dimensional objects etc (in other words the device which optically scan images and convert them in to digital images) from magazine pages , posters , photographic prints and from other similar source for display and editing in computer. They scanning the documents in black and white or also in color depends upon there configuration.
Flatbed scanners - Flatbed scanners are used in home and offices. They are the most commonly used scanners and they also known as desktop scanners. For holding a paper sheet etc , these have large glass surface and under the glass scan head is moved. The light source move with same light and speed across the document and give a uniform exposure to document. The light reflected back to machine after shining on the document and after it reflected on lens by mirrors.
Flatbed scanners have two common types -
1) CIS - Contact image sensor
AND
2) CCD - Charge coupled device
Some models came as all in one device , they work as scanners , printers , fax machine and copy machines.
Sheet-fed-scanners - They work like flatbed scanners but in sheet-fed-scanners the document moved and scan head is immobile. It means that image fed through scanners and move further along beam to be read and beam is not moving .In flatbed scanners we have insert and remove each page but sheet-fed-scanners scan large stack of papers. They have additional tray for small items. They are also known as automatic document feeders scanner (ADF scanner) and are used in offices to scan documents and by archives or libraries for scanning books.They also used by editors and by professional photographers. They resembles inkjet printers and they scan graphic images in to there original form. They are having two types -
Reserve automatic document feeders (RADF) - They scan only one side.
Single pass automatic document feeder (SADF) - scan both sides and convenient in use.
Handheld scanners - Handheld scanners are not expensive and they are smaller than desktop counterparts. They are used for scanning physical documents into digitized print document that are stored , transferred , edited and emailed digitally. They can scan items of all sizes as they are rely on steady hand but produce lower quality output in comparison to flatbed scanners. With the help of tray (for keeping straight) you can move it over the material you want to capture. Experience is must for operating them .
Drum scanners - These scanners are used by publishing industry to capture detailed images. They are used for scanning transparent and reflective materials on a very high resolution. During scanning the spun speed reached greater than 1000 RPM , the transparencies and photograph are clamped and taped in a drum (cylinder). These scanners use analog light to capture image resulted in detail color channel and converted the image to digital file. A reflected light source is used for opaque items and from center of drum light is directed for transparencies. RGB values filtered by mirrors and these values send to cylinder scanners photo-multiplier tube (PMT).
Portable scanners - As the name indicates you can use them on the go. When you scan the text or other data , it is stored on these scanners. After storing you can transfer it to your computer by using a cable or by wireless connection. These scanners have batteries for there operations.
Drum scanners - These scanners are used by publishing industry to capture detailed images. They are used for scanning transparent and reflective materials on a very high resolution. During scanning the spun speed reached greater than 1000 RPM , the transparencies and photograph are clamped and taped in a drum (cylinder). These scanners use analog light to capture image resulted in detail color channel and converted the image to digital file. A reflected light source is used for opaque items and from center of drum light is directed for transparencies. RGB values filtered by mirrors and these values send to cylinder scanners photo-multiplier tube (PMT).
Production scanners - These scanners are like flatbed scanners but provide faster operations for high volume work. They have a feed device to scan large volumes of documents quickly.
Bar code laser scanners - They are used for reading and decoding of data in bar codes. They also have some types such as -
Ring scanners
Integrated scanners
Tethered and wireless scanners.
Flatbed scanners are easy to use and frequently used in home and offices complexes .
Flatbed scanners are easy to use and frequently used in home and offices complexes .
MR. DEEPAK PAWAR has been working as Finger Print Expert / Police Officer in Finger Print Bureau , Delhi Police at New Delhi since 2001 . He is the senior most Finger Print Expert , attending / visited several scene of crime and solved many crime cases .He has passed M.Sc (Chemistry) and he is the Member of International Association of Identification . He is the Member of Delhi Police welfare association . He is supervising the Forensic , New Delhi District , Mobile Crime Team . He is one of the Expert in the Special Investigation Team held for investigation of important cases . He has been giving fingerprint proficient training to Delhi Police personnel's . He has been Presented / giving lectures on topics related to forensic science . He is also making examination paper of Finger Print proficient course . He is awarded with Police Medal by MHA and Delhi Police.