M3 - U3 - S7 - Scanners and Cameras

Scanner - Digital File - Flatbed Scanner - Ambient Light - Cold Cathode Fluorescent Lamp (CCFL) - Charged Coupled Device (CCD) Array - Pixels - Proportion - Light Intensity - Resolution - Pixels Per Inch (PPI) - Sheet-fed Scanner - Windows Image Acquisition (WIA) Software - Optical Character Recognition (OCR) Software - Digital Camera - Flash Memory Card

Scanner

• Imaging device

• Creates a digital file from a page of print, photo, or another object

• Typically handles flat objects

• Flatbed Scanner

• Sheet-fed Scanner

The 2 types of scanner in ITF+

Flatbed Scanner

• Works like a photocopier

• Object is placed on glass faceplate and cover is closed

  • Prevents ambient light affecting image

Flatbed Scanner Mechanics

• Bright light usually from a Cold Cathode Fluorescent Lamp (CCFL), illuminates the object

• The image is recorded using a Charge Coupled Device (CCD) array

Charged coupled device (CCD)

• Composed of picture elements (pixels) that generate an electrical charge in proportion to the intensity of light shined on them

• Records the image whilst CCFL is shining on it

  • This is used to create a digital image

Scanner Quality

• Determined by resolution (number of pixels) in the CCD array

  • Measured in Pixels per Inch (PPI)

Sheet-fed Scanner

• Alternative to flatbed scanner

• Only handle fairly thin paper objects

• TWAIN

  • Older

• Windows Image Acquisition (WIA) Software

  • Presents options for image output format + tools for correcting image

The 2 types of scan acquisition software (ITF+)

Optical Character Recognition (OCR)

Software that converts text images into a computer-editable text document

Digital Camera

• Stores images on flash memory based card

  • E.g. CompactFlash or SecureDigital

• Can transfer images via:

  • USB | Memory Card Slot | Wi-Fi