Scanning Devices : Scanning Devices Copy data from a source
Scanners take paper and convert it into a bitmap
Types of scanners
Bar code readers
Character and Mark recognition Optical Scanners : Optical Scanners Convert text or drawings into machine readable format
Can be displayed, printed, or stored
Types of optical scanners
Source placed on glass surface
Image scanned from below
Handheld device that slides across source Slide 3: Flatbed scanner If we talk about scanners, thus we mean usually flatbed scanner. The scan documents (texts, photo, diagrams etc..) are put on a glass plate like a copier, under which a carriage with an exposure item and the read head moves. Then the picture is scanned The picture information is entered by a CCD (Charge Couple Device). CCDs are semiconductor chips, with an array of photo-sensitive cells, which are used for the transformation from electromagnetic waves of light into electrical signals. Bar Code Readers : Bar Code Readers Photoelectric scanner
Using Optical Recognition, a light beam scans the item and changes it into electrical impulses for processing Contain photoelectric cells that read bar codes
Read bar codes
Alternating black & white vertical bars
Universal Product Code (UPC)
Seen in grocery stores, retail stores Character & Mark Recognition : Character & Mark Recognition Magnetic-ink character recognition (MICR)
Reads magnetically encoded characters
Optical-character recognition (OCR)
Optical character recognition (OCR) converts bitmap back into text
• different fonts create problems for simple “template matching” algorithms
• more complex systems segment text, decompose it into lines and arcs, and decipher characters that way
Optical-mark recognition (OMR)
Senses presence or absence of marks Types of Scanners : Types of Scanners A flatbed scanner scans one sheet at a time by laying the sheet face down on the bed of the scanner
Sheetfed scanner use motorized rollers to feed the document across the scanning mechanism
Handheld scanner-portable device that requires users to pass the scanning element over the item to be scanned Some More Optical Recognition Methods : Some More Optical Recognition Methods Bar codes-each product has a unique product code (UPC) represented by a pattern of bars
Bar code scanner scans the bars using reflected light which is then processed to retrieve product information assigned to that bar code
Handwriting Recognition Network Scanning is New : Network Scanning is New Scanners are typically envisioned as connected to a co-located host computer.
Submitting “Jobs” to network scanners is unnatural since a walk-up user must be present to submit the originals anyway.
Jobs may be most naturally started at the scanner and not at a workstation.
Will be more prevalent as networked MFPs provide scanning capability. Scanning Purpose : Scanning Purpose Archive-Communicate
recording a facsimile of an image, such as a form or a signature for storage, transmission or reproduction. Parameters and area probably well defined, fidelity important. Includes Copying, Fax.
Capturing an image for inclusion in a document or display, often with modification, scaling, cropping, etc. Parameters may not be known and area to be scanned may be inconsistent, fidelity important.
Processing an image for analysis or interpretation, such as OCR or feature analysis. Parameters and area probably well defined, fidelity not too important for extraction. Analysis required very high fidelity. Scanning Devices : Scanning Devices Character and mark recognition devices
Scanners that recognize special characters & marks
Magnetic ink character recognition (MICR)
Optical-character recognition (OCR)
Optical-mark recognition (OMR) Slide 11: We finds CCD CHIPS in scanners, digital photo cameras and video cameras (analogue and digital).
During subsequent treatment of the signal in the device the signal must be converted by a A/D converter (analogue/digital) into digital data. Scanners operate with the RGB Spectrum, i.e. the colors of the flash spectrum are filtered into the three basic colors red, green and blue and processed in the transmission path as RGB signals. The quality of a scanner depends particularly on the maximum resolution in dpi (dots per inch). Slide 12: A further test of value for scanners is their operating speed. On the one hand it depends on the quality of the mechanical and electronic components, on the other hand on the type of its data interfaces (plug link). Devices at the printer link are slow. Scanners with SCSI link are particularly fast, however they need a SCSI card. Many scanners come with USB link, which is faster and easier to attach. Scanners : Scanners Scanners read and interpret information on printed matter
The information is converted to a format for storage Optical Mark Recognition : Optical Mark Recognition Grades test
The sense marks are compared on the test by the scanner
Corrections are calculated Scanners : Scanners Scanners capture and digitize printed images. There are several types of scanners:
Sheet-fed scanners Sheet-fed : Sheet-fed Item to be scanned is to be pulled into a stationary scanning mechanism
Smaller and less expensive than flatbed scanner DRUM SCANNER : DRUM SCANNER Item to be scanned rotates around stationary scanning mechanism
Very large and expensive
Used in the publishing industry. Slide 18: IT Fundamentals 18 Examples of Direct Entry Input Devices MICR : Used with cheques OMR : Tattslotto & TAB
OCR : Scan type-written pages…. Scanners