| Lanjut ke konten Multiple Choices Buat situs web Anda dengan WordPress.com Mulai Presentation on theme: "Advanced Computer Science (Computer Peripherals) Fourth Year (First Semester) Dr. Hany Mahgoub TANTA UNIVERSITY FACULTY OF SCIENCE Lecture Seven."— Presentation transcript: 1 Advanced Computer Science (Computer Peripherals) Fourth Year (First Semester) Dr. Hany
Mahgoub TANTA UNIVERSITY FACULTY OF SCIENCE Lecture Seven 2 Input Devices 3 Outline KeyboardsKeyboards Pointing DevicesPointing Devices 1.Mouse 6. Touch Screen
2.Trackball 7. Light pen 3.Touchpad 8. Electronic Pen 4.Pointing Stick 9. Graphics Tablet 5.Joystick Scanners and Reading DevicesScanners and Reading Devices Digital CamerasDigital Cameras Audio InputAudio Input Video InputVideo Input 4 Trackball Trackerballs are
used on laptops or by people who may have difficulty moving their fingers. A large ball is rotated at the top of the device and the user’s palm turns the ball and hence the pointer on screen. (Trackerballs have mostly been replaced by trackpads on laptops.) Around the ball mechanism, usually a trackball also has one or more buttons that work just like mouse buttons. Trackball
5 Touchpad A touchpad or trackpad is a small, flat, rectangular pointing device that is sensitive to pressure and motion. To move the pointer using a touchpad, you slide your fingertip across the surface to the pad. Some touchpad have one or more buttons around the edge
of the pad that work like mouse buttons. Many notebook computers have a touchpad that allows you to move the pointer with the tip of your finger. 6 Pointing Stick A pointing stick or trackpoint is a pressure-sensitive pointing device shaped like a pencil
eraser. Because of its small size, the pointing stick is conveniently positioned between keys on the keyboard. To move the pointer using a pointing stick, you push the pointing stick with your finger. The pointer on the screen moves in the direction that you push the pointing stick. Some notebook computers use a pointing stick to control the movement of the pointer.
7 Joystick A joystick is a pointing device that has a vertical lever mounted on a base, usually used for running game and simulation software such as a driving or flight simulator. You move the lever in different
directions to control the actions of a vehicle or player. The lever usually includes buttons called triggers that you can press to activate certain events. A joystick helps the user control the actions of player and vehicles in game and simulation software. 8 Touch Screen A touch
screen is a monitor that has a touch-sensitive panel on the screen. You interact with the computer by touching areas of the screen with your finger that acts as an input device. Touch screens often are used in banks located in stores, hotels, airports, and museums. You interact with the touch screen by touching areas of the screen with your finger. 9 Light pen A light pen is a handheld input device that contains a light-source or can detect light. You press the light pen against the surface of the screen or point the light pen at the screen and then press a button on the pen. Light pens are used in applications where desktop space is limited such as in the health-care or industrial field. Selections with a light pen.
10 Graphics Tablet Architects, mapmakers, artists, and designers create drawings and sketches by using an electronic pen on a graphics tablet. A graphics tablet, also called digitizer, consists of a flat, rectangular plastic board used to input
drawing, sketches, or other graphical data. Each location on the graphics tablet corresponds to a specific location on the screen. When you draw on the tablet with an electronic pen, the tablet detects and converts the movements into digital signals that are sent into the computer. 11 These
pens are quite sophisticated, featuring erasers and programmable buttons. Some digitizing tablets also use a crosshair device called cursor instead of a pen. - Businesses ( electronic signatures) Stylus, graphics tablet, and cursor are used by artists, architects, mapmakers, and designers.
12 Scanners and Reading Devices Optical recognition systems use a light beam to scan input data and convert it into electrical signals, which are sent to the computer for processing. Devices that capture data
directly from source documents include optical scanners, optical character recognition devices, optical mark recognition devices, bar code scanners, and magnetic-ink character recognition readers.
13 Optical Scanner An optical scanner, usually called a scanner, is a device that can convert text, drawing, or picture into computer- recognizable data by using a form of optical recognition. In a
process called imaging, a scanner converts source documents to an electronic version, which can then be stored on a disk and retrieved when needed. A variety of scanners are used to read and interpret information on printed matter. Four common types of scanners are flatbed, sheet-fed, drum, and handheld. 14 How an optical scanner works.
15 The types and uses of scanners. 16 The higher the resolution, the sharper and clearer the resulting image. dotsThe electronic version of
scanned material is in the form of rows and columns of dots called a bitmap. The density of the dots, known as the resolution, determines sharpness and clearness of the resulting image. The higher the resolution, the better the image quality, but the more expensive the device. Resolution typically is measured in dots per inch (dpi). The more dots per inch, the sharper and clearer the resulting image. For example, a 600x1200 dpi scanner has 600 columns and 1200 rows of dots.
17 Optical Character Recognition (OCR) OCR is a technology that involves reading typewritten, computer- printed, or handwritten characters from ordinary
documents and translating the images into a form that the computer can understand. Most OCR devices include a small optical scanner for reading characters and a software (OCR software) for analyzing what is read. OCR devices read characters printed using an OCR font. During the scan of a document, an OCR device determines the shapes of characters by detecting patterns of light and dark. OCR software then compares these shapes with predefined shapes stored in memory and converts the shapes into
characters that computer can understand. 18 An OCR use. 19 Optical Mark Recognition (OMR) OMR devices read hand-drawn marks such
as small circles or rectangles. A person places these marks on a form, such as a test, survey, or questionnaire answer sheet. The OMR device first reads a master document, such as an answer key sheet for a test, to record correct answers based on patterns of light; the remaining documents then are passed through the OMR device and their patterns of light are matched against the master document.
20 OMR devices. 21 A bar code scanner A bar code scanner uses laser beams to read bar codes. A bar code is an identification code that consists of a set of vertical lines and
spaces of different widths. The bar code scanner uses light patterns from the bar code lines to identify the item. There is a variety of bar-coding systems. Each industry uses its own type of bar code. The retail and grocery stores use the Universal Product Code (UPC). The U.S. Postal Service uses a POSTNET bar code. 22 The Bar code scanner. 23 A magnetic-ink character recognition (MICR) A magnetic-ink character recognition (MICR) reader is used to read text printed with magnetized ink. MICR is used almost exclusively by the banking industry for check processing. Each
check has precoded MICR characters on the lower-left edge; these characters represent the bank number, your account number, and the check number. Each check is inserted into an MICR reader, which sends the check information to a computer for processing. 24 An MICR reader.
25 Digital Cameras A digital camera allows you to take pictures and store the photographed images digitally instead of on traditional film. dots per inch (dpi)1-megapixelOne factor that affects the quality of a digital camera is its resolution. dots per
inch (dpi) or pixel,1-megapixel (million pixel). There are three basic types of digital cameras: studio cameras, field cameras, and point-and-shoot cameras. A studio camera, the most expensive and highest quality of the three, is a stationary camera used by professional studio work. A field camera is a portable camera that has many lenses and other attachments. It often used by photojournalists. A point-and-shoot camera is more affordable and lightweight and provides acceptable quality
photographic images for the home or small business user. 26 How a digital camera works. 27 A digital vision-inspection system.
28 Audio Input Audio input is the process of entering (recording) any sound into the computer such as music, speech, or sound effects. To record high quality sound, your computer must have a sound card. Sound is entered via a device such as a microphone, tape
player, or audio VD player, each of which plugs into a port on the sound card. External Musical Instrument Digital Interface (MIDI) devices such as an electric piano keyboard also can connect to the sound card for audio input. The use for a microphone is voice recognition. Voice recognition or speech recognition, is the computer's capability of distinguishing spoken words. 29 How voice recognition works. 30 Video Input Video input is the process of entering a full-motion recording into a computer and storing the video on a storage medium. A new generation of video cameras
produces digital signals. A digital video (DV) camera is a video camera that records video as digital signals, instead of analog signals. In addition to video, you also can capture still frames with these cameras. A DV camera connects directly to a parallel port or USB port on the computer. 31 Video files can
require huge amounts of storage space. Video often is compressed to decrease the size of the files. Video compression works by recognizing that only a small portion of a video image changes from frame to frame. A video compression program might store the first frame and then store only the changes from one frame to the next. Before you view the video, the program decompresses the video segment.
32 A PC video camera is a DV camera that allows the home user to record, edit, and capture video and still images and to make video telephone calls on the Interne. A PC video camera. A Web cam, also called a cam, is a video camera
whose output displays on a Web page. A Web cam attracts Web site visitors by showing images that change regularly. |
Architects, mapmakers, designers, artists, and home users create drawings and sketches on a
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