Image Capture Devices These devices are used to capture the images from outer environment. Following are the important image capture devise: 1. Digital Camera 2. Digital Video Camera 3. Camcoder 4. Webcam 5. Scanner
Digital Camera A digital camera is an important image capturing device. It has a grid of light sensors that captures image of outer environment. The sensors generate analogue signals representing the image and send these signals to the embedded/built-in processor of camera. This processor digitizes the analogue signals and displays them on the LCD screen of camera. A digital image is made up of pixels. A pixel is a small rectangular sized picture element. A digital image with more number of pixels has good resolution/image quality. The camera processes and stores the images in non-volatile memory or it may save images on removable digital storage.
Digital Camera Advantages of digital camera are below: 1. There is no repeated cost of purchasing and processing films. 2. There is no long delay in processing which means you can preview the captured image immediately and delete if it is not good enough. 3. It is easier and quicker to edit the digital images. 4. A digital image can be easily sent and shared on social media networks. 5. A digital image can be attached and sent with an email easily.
Digital Video Camera A digital video camera captures the sequence of digital images at the rate of usually 30 images per second. This sequence of digital images is stored as a video file. The file may also include audio as well.
Camcoder It is a portable digital video camera that has facility of recording. It captures image sequence and stores them as a video file.
Webcam Webcam is used in video calling or video conferencing. It captures images and sent them to computer where computer transmits them over Internet so that other party can see. Webcam is not used for recording video but it is used for broadcasting video. It can also be used for remote monitoring of a place or a building.
Scanner A scanner creates a digital photograph of a paper document. A scanner has a single row of hundreds of light sensors. It throws light on the document and each sensor generate an analogue signal depending upon the intensity of light it receives. The built-in computer/processor of scanner receives these analogue signals from sensors and digitizes them, processes them and finally send to the computer. The processor of computer reconstructs the image of document on the basis of signals received from scanner and display the scanned image on LCD or monitor screen. The scanners we usually use are 2D scanners. A 3D scanner is a device that analyzes a real-world object or environment to collect data on its shape and possibly its appearance (i.e. color). The collected data can then be used to construct digital three-dimensional models.
Sound & Music Capture Devices There are two main devices: 1. Microphone 2. MIDI (Musical Instrument Digital Interface) A microphone (Mic) is a very common sound capturing device. It receives sound from outer environment and coverts it into analogue signals. The microphone is connected with the soundcard of computer. The soundcard has an Analogue-to-Digital Converter (ADC) which converts the received analogue signals into digital signals. Microphone is usually used to make voice calls over Internet which is known as VoIP. Microphone can also be used with speech recognition software that will receive the voice signals coming from microphone and will convert them into the text which is really helpful for those with physical disabilities. One disadvantage is that, sometimes, a speech recognition software may translate voice into incorrect text.
MIDI (Musical Instrument Digital Interface) It is a musical keyboard which is connected to the computer through a special MIDI interface. When a key is struck on the musical keyboard then keyboard sends signals representing particular pitch and volume related to that key. The MIDI software can be used to record the music produced by stroking the keys of MIDI keyboard. It can also edit as well.
Remote Control A remote control is a small hand-held device with a relatively small number of labelled buttons to perform various operations. It is used to operate Television, satellite or cable TV receiver, DVD player, home entertainment system etc. When a button is pressed, the remote control sends a coded infrared (IR) signal to the equipment to perform an operation corresponding to that signal. Advantage is that you can control the devices wirelessly while sitting at small distance. Disadvantage is that the Infrared (IR) signal may interfere with other equipment.