Flatbed peripheral devices. As they all have flat

Flatbed Input DevicesThe word flatbed input devices are generally points to the Scanners. Scanners are the very useful input peripheral devices. As they all have flat surfaces to scan the documents they are referred as Flatbed input devices. Now the formal introduction of Flatbed Scanners are as below:Flatbed Scanners are an optical scanner that uses a flat surface to scan documents. The scanner can capture all elements of the document and do not require any movement of the documents. Flatbed Scanner are effective Scanners for sensitive materials such as vintage documents, photographs, and other fragile documents.WORKINGDifference from the other types, flatbed scanners only requires the user to lay the documents onto the glass and close the lid. Most of the flatbed scanner have an adjustable lid which can be raised to allow thicker material to be scanned. A transparent media adapter found in some flatbed scanner. That can scan film and glass negatives. Some of them can also have additional features like automatic document feeding and wireless connectivity. They can be connected via USB to the computer.Advantages of Flatbed ScannerThey can scan larger images and are more accurate than handheld Scanner.The price of Flatbed scanners are comparatively less.They are also capable of interfacing with computer networks so multiple computers and user can access the devices.It’s pretty much easy to use.CCD ScannerFull Form of CCD is Charged Couple Device. This is the same type of imaging sensor found inside a digital camera. CCD uses an actual lens to reduce the full image onto the imaging sensor. This method is great for capturing very high resolution details along with widened color space. A flat CCD scanner typically consists of a glass panel (or plate) under which there is a bright light (often xenon, LED or a fluorescent cathode) that illuminates the panel and an optical assembly that travels in the sweep CCD. CCD scanners typically contain three rows (rows) of sensors with red, green, and blue filters. The light source, normally a cold cathode light, is reflected by the original, deflected by mirrors and captured by a lens on the sensor. This involves capturing lightweight CCD elements. In some cases, the CCD elements may also have a micro-lens in front of each photodiode to more efficiently collect light.Advantages of CCD ScannerSignal/noise ratio is high because of florescent lamp light sourceInsensitive of focusing depth because of cameras with apochromatic lenses.Disadvantages Of CCD ScannerGenerally price of CCD is bit highIt’s not simplest to use and the technology which is used in this is also little bit complex.Optical resolution is lowLens distortion is a problemCIS SCANNERThe word CIS stands for Contact Imaging Sensor. Instead of using a standard lens to reduce the original image on the sensor, CIS technology uses many fiber optic lenses to transfer information from the original image to a series of sensors. CIS technology is cheaper than traditional CCD models, that is, there are no cameras to calibrate and the sensors are software controlled, there is much less maintenance with a scanner CIS But, due to the shallow depth of field of optics, the fold line and wrinkles will create an image with CIS. In addition, there is a reduction in color space information with CIS. Unless you want to capture primarily primary colors, CIS may want you a little bit more.However, keep in mind that although CIS physical technology has some limitations, many manufacturers have overcome this problem by implementing sophisticated software that offsets CIS deficiencies. A good example is the Canon Image Logic used by all Canon / Océ wide format systems.Working of CIS ScannerThe CIS scanner consists of a mobile set of red, green and blue strobe LEDs for illumination and a monochromatic photodiode array connected under a rod lens array for light collection. The images to be scanned are placed face down on the glass, an opaque lid is lowered to exclude the ambient light and the sensor array and the light source are moved on the glass, and the entire area is read. An image is visible to the detector only by the light it reflects. Transparent images do not work in this way and require special accessories that illuminate them from above. Many scanners offer this option.Advantages of CIS ScannersLess CostHigh reliabilityMore compactNo stitching requiredHigher optical resolutionNo lens distortionDisadvantages of CIS ScannerSensitive to focus depth & Lower signal/noise ratio due to LED light sourceHand Scanner Hand scanners come in two forms: documents and 3D scanners. Hand Document Scanners are handheld devices that are dragged over the surface of the image to be scanned. Scanning documents in this way requires a firm hand, as an irregular scanning speed would produce distorted images: a small light on the scanner would indicate if the movement was too fast. In general, they have a “start” button, which is held by the user during the scan; some switches to set the optical resolution; and a roll, which generates a clock pulse for synchronization with the computer.Most hand scanners were monochromatic and produced light from a series of green LEDs to illuminate the image. A typical hand scanner also had a small window through which you could see the document being scanned. They were popular in the early 1990s and generally had a proprietary interface module.While the popularity of document scanning has declined, the use of portable 3D scanners remains popular for many applications, including reverse engineering, industrial design, inspection and analysis, digital manufacturing and applications. medical to compensate for the irregular movement of the human hand, most 3D scanning systems rely on the placement of reference markers, usually reflective adhesive tabs that the scanner uses to align elements and mark positions in space.SMARTPHONE SCANNER APPSSmartphone scanner apps can be broadly divided into three categories: Document scanning apps: –                                                                                                                                           These are primarily designed to handle documents and output PDF files – although some can also output JPEGPhoto scanning apps: –                                                                                                                         These output JPEG files , and have editing functions useful for photo rather than document editing. QR scanning apps: –                                                                                                                                          These can use scanned QR images to automatically search the internet for related information. Nowadays Smartphone cameras have achieved a resolution and quality that allows for quality scans by taking a picture with the phone and using a scanning application for processing (for example, bleaching the background of a page, correcting the distortion that a document output is a correct rectangle, converting to black and white, etc.)Most smartphone platforms now have a range of scanner applications available. These applications can typically scan multi-page documents using multiple camera exposures and send them to a PDF document or as separate JPEG images. Some smartphone scanning applications can also save documents directly to online storage locations, such as Dropbox and Evernote, e-mail or fax via e-mail to fax gateways.


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