Describe The Various Techniques Used For Video Input

Video input, or video capture, is the process of entering a full-motion recording into a computer and storing the video on a storage medium. Many video devices use analog video signals. To input video from these devices, the device is plugged into a video capture card, an expansion card that converts the analog signal into a digital signal the computer can understand. A digital video (DV) camera is a new generation of video camera that records video as digital signals, instead of using analog signals, and therefore does not require a video capture card. Video files can demand huge amounts of storage space. Video compression reduces the size of video files by recognizing that only a small portion of an image changes from frame to frame. Instead of storing every frame in its entirety, a video compression program might store an initial frame and then store only the changes from one frame to the next. A video decoder is a card that decompresses video. A video digitizer can be used to capture an individual frame from a video and save the still picture in a file.

Explain How Scanners And Other Reading Devices Work

Scanners and optical readers can capture data from a source document, which is the original form of the data. A scanner is a light-sensing input device that reads printed text and graphics and then translates the results into a form a computer can use. One of the more popular scanners is a flatbed ¹ scanner, which works similarly to a copy machine except it creates a file of the document in memory instead of a paper copy. Many scanners include OCR software, which converts a scanned image into a text file that can be edited. An optical reader uses a light source to read characters, marks, and codes and converts them into digital data that a computer can process. Three types of optical readers are optical character recognition, optical mark recognition, and bar code scanner ². Optical character recognition ³ (OCR) is a technology that reads typewritten, computer printed, or handwritten characters from ordinary documents and translates the images into a form that the computer can understand. Optical mark recognition ⁴ (OMR) devices read hand-drawn marks such as circles or rectangles. A bar code scanner uses laser beams to read bar codes, which are identification codes consisting of vertical lines and spaces of different widths. Another type of reader, called a magnetic-ink character recognition ⁵ (MICR) reader, reads text printed with magnetized ink and is used almost exclusively by the banking industry.

In general, scanners and reading devices increase input accuracy and efficiency by reducing the role of the weak link in the input process – the human operator. Optical readers are highly specialized. Devices that read one set of codes, marks, or characters may not be able to read another.

Bar codes minimize input errors, keep inventories up to date, help to track sales trends, and eliminate the need to price individual items. The identifying numbers on a UPC ⁶ code can be entered if the scanner fails. This number is not the item’s cost – prices are obtained from a database when the item is scanned.

Identify Alternative Input Devices For Physically Challenged Users

Whether at work or at home, it may be necessary to obtain input devices that address physical limitations. Voice recognition is ideal for blind or visually impaired users ⁷, but several other input devices also are available. A keyguard, which is placed over the keyboard, allows people with limited hand mobility to rest their hands on the keyboard and guides a finger or pointing device so that only one key is pressed. Keyboards with larger keys and on-screen keyboards on which keys are pressed using a pointing device also can help. Pointing devices such as small trackballs controlled with a thumb or one finger and head-mounted pointers also are available for users with motor disabilities. Two new developments are gesture recognition and computerized implant devices. With gesture recognition the computer will be able to detect human motions. Computerized devices implanted in the brain will allow paralyzed individuals to transmit signals to the computer.

PART II

TEXT 1 OUTPUT