Imaging Devices on your system

  1. Basics: Image Input and Output

    1. Concepts of Input and Output

    2. Input:

      1. Bar code readers
        /Magnetic stripe readers
        /Laser readers

      2. Digital Cameras

      3. Graphic Tablets

      4. Light Pens

      5. Mice

      6. Scanners

      7. Touch Pads

      8. Touch Screens

      9. Web Cameras

    3. Output:

      1. Video Monitors

      2. Display Adapters

      3. Video Editors

      4. Plotters

      5. Printers

  2. Basics: Image Resolution

    1. Concept of Resolution

    2. Input:

      1. Bar code readers
        /Magnetic stripe readers
        /Laser readers

      2. Digital Cameras

      3. Graphic Tablets

      4. Light Pens

      5. Mice

      6. Scanners

      7. Touch Pads

      8. Touch Screens

      9. Web Cameras

    3. Output:

      1. Video Monitors

      2. Display Adapters

      3. Video Editors

      4. Plotters

      5. Printers

  3. Color Depth

    1. Input:

      1. Bar code readers
        /Magnetic stripe readers
        /Laser readers

      2. Digital Cameras

      3. Graphic Tablets

      4. Light Pens

      5. Mice

      6. Scanners

      7. Touch Pads

      8. Touch Screens

      9. Web Cameras

    2. Output:

      1. Video Monitors

      2. Display Adapters

      3. Video Editors

      4. Plotters

      5. Printers

Concepts of Input and Output
       There are several places where imaging devices come into play on your
system. They all have one one thing in common and that is that they transpose pixels or other co-ordinates into a computer readable
 representation. On the output side the devices include  Monitor Displays, Video adapters, Video Editors, Printers and Plotters. On the Input side there are Pointer Devices like Mice, Touch pads, Touch Screens, Light pens and Graphic Tablets as well as Digital Cameras, Scanners, Bar Code readers and Web Cameras.
      Below is the general concept of these devices:
           Output:
                Video Monitors: These devices accept digital or analog (depending
                     on the type of display) signals from a Video Adapter and draw
                     the image repeatedly onto the display surface.

                Video Adapters: Convert the Computer Binary data to be
                     displayed into a digital or analog signal acceptable to a video
                     Monitor.
                Video Editors: Convert Computer Binary data to be recorded into
                     analog NTSC or PAL signals acceptable to Video Recorders
                     like VCR's, Video Printers, and Direct Video Monitors such
                     as those used by security systems. They may also be capable
                     of operation as a video adapter and may also include the
                     abilities to input NTSC or PAL format Video from VCR's and
                     standard Video Camera's.
                 Printers: Convert textual data represented by letters and numbers
                     into graphical blocks of dots which are drawn across the print
                     line. Each letter or number is referred to as a character and may
                     consist of 5 to 12 dot patterns that are printed when the
                     character is encountered. In graphics mode, printers print a
                     series of dot patterns in the order received. Certain patterns
                     are recognized as commands to change colors, advance to the
                     next line, or define that the next x number of patterns is
                     graphics.
                 Plotters: Generally, a plotter receives a series of X Y and color
                     bytes which cause the plotter print head to move to the x/y
                     position of the page and print a single dot of the indicated color.
            Input:
                Mice: Convert user actions of mouse movement and clicks into
                     Binary data that represents the X and Y distances moved and
                    /or the state of the buttons (up/down).
                Touch Pads: A touch Pad is very similar to a Mouse other than
                   instead of the user moving the mouse to reflect the change, the
                   user taps a stationary small pad to indicate a click and touches
                   and drags his/her finger across the surface to indicate movement.
                Touch Screens: Are similar to Touch Pads other than they are
                   either added to the front of a monitor or are part of the monitor
                   screen.  Operation is like that of the Touch Pad but the whole
                   screen surface if usable for making the representation.
                Light Pens: A light pen uses the current display line and display
                    column and a pressure sensitive switch on the end of the pen
                    to set the X and Y position and button state as being (up/down).
                   when the state = up movement of the pen position is ignored.
                Graphic Tablets: Primarily used for drawing these devices send
                    the X and Y position of a stylus on the tablet surface into the
                    computer.
                Bar Code Readers: Used in business applications a bar Code
                    reader sends a laser light out and reads the result of light
                    reflected back. (Security and bank card readers do roughly
                   the same thing except they read a magnetic strip rather than
                   reflected light. Newer Security and bank cards work closer
                   to the principals of CD's where a laser burns the binary image
                   onto the card surface).
                Digital Cameras: Use an image sensor that translates the image
                   in front of the camera into a series of Red Blue Green pixels
                  which arranged in both the X and Y direction and each R G B
                  pixel also has an intensity of each color. A Digital Camera may
                  have a built in LCD display so you can see what you are about
                  to take a picture of. When you actually take the picture it is
                  recorded into memory which can be later downloaded as an digital
                  image file.
                Scanners: Use an image sensor that translates the image
                   in the current scanner line into a series of Red Blue Green pixels
                   which arranged in both the X and Y direction and each R G B
                   pixel also has an intensity of each color. When you actually scan
                   a picture it is transferred 1 line at a time into memory which is
                   then saved usually to a temporary file till the whole image has
                   been retrieved.
                Web Cameras: Very similar to Digital Cameras, a Web Cam
                   sends a continuous stream of pictures known as frames just
                   as if you were taking 10 to 30 pictures per second with a Digital
                   Camera. When you use a Web Cam in stream mode the target
                   of all the frames sent is usually a PC somewhere over the
                   internet and once a frame is sent it is lost forever. When you
                   use the snapshot mode the frame is converted into an image
                   format and saved as an Image file. Some Web Cams also
                   can record the frames as an AVI movie file.

Concept of Resolution
       Resolution defines the number of plot points that represent an image
or movement. The more plottable points the more precise the device is.
There are two sides to the resolution equation, on one side there is maximum
defined resolution a device can handle, and on the other side there is the
current defined resolution that is being desired. The current defined
resolution can at no time exceed what the device can handle. Attempts to
exceed what the device can handle can and usually does result in device
failure. Each device works with resolution in it's own specific way as detailed
below:
      Video Monitors:
These display devices have something called Dot Pitch
            which in many circles defines the number of millimeters a single pixel
            occupies on the display. Values typically range between .22 and .35.
            The smaller the dot pitch value, the greater the clarity of the displayable
            image. Monitors have a maximum resolution which defines the maximum
            number of dots (pixels) which can be displayed across and down the
            display. There are 2 main types of display CRT and LCD.
              A CRT display repeated draws the most current image view. Changes to
            the image view are reflected in the next redraw. If the image sent to the
            monitor is at a resolution lower than the monitors maximum then many dots
            may be used to show 1 pixel. At the maximum resolution 1 dot = 1 pixel.
            A CRT display has brightness, contrast, width, height, and V/H  adjustment.
            A CRT works equally well for Textual applications as it does for Graphics
            but tends to be both bulky and heavy. The displayable area of a 17" monitor
            is about 15" because the monitor cannot display right to the edge of the
            CRT.
              An LCD display redraws the image when there has been a change.
            Changes to the image are reflected in the next redraw. The Image has a
            certain afterglow (shadow the the previous image that fades away).
            Generally, an LCD display should only be run at it's ideal maximum
            resolution where 1 dot = 1 pixel. An LCD display uses a contrast factor
            which can range from 150:1 to 600:1 where you want the highest ratio
            you can get. Due to the slower response of LCD, they are best suited
            to Textual and still graphics rather than streaming graphics found in games
            and videos. The LCD is thin compact and light and can display right to the
            edge so 15" = 15".
                     Typical Monitor Resolutions:
                         640 x 480
                         800 x 600
                       1260 x 900
                       1440 x 1200
      Video Adapters:
      Video Editors:
      Printers/Plotters:
      Bar Code Readers / Magnetic Stripe Readers / Laser Stripe Readers:
      Mice:
      Digital Cameras:
      Graphic Tablets:
      Light Pens:
      Scanners:
      Touch Pads:
      Touch Screens:
      Web Cams: