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level: Input device

Questions and Answers List

level questions: Input device

QuestionAnswer
What is the definition of 2D scannersAn input device that is used as a method of inputting paper documents and storing them in computer as digital form
How does 2D scanners work?1. Documents are placed on the glass panel of the scanner 2. A bright light is shined onto the document 3. A scan head moves under the panel, scanning the document 4. An image is produced and sent to a lens by mirrors, which focuses on the image 5. The focused image then falls onto the CCD Charge Couple device which consist of Integrated Circuit coated by silicon 6. It scans image and makes it into digital form
What does CCD stand forCharged Couple Device
What is CCD made up ofIt is made up of thousands of light-sensitive elements, which produces electrical charges when light is shined on
After document is scanned by the scan head, where has it be sent to?A lens using mirrors which focuses on the documents image
After the document is sent to the lens of mirrors, where does the focused image go?It falls onto a Charged Couple Device (CCD)
What does the CCD consist ofIt consists of integrated circuit coated by silicon
What does a scan head doA scan head moves from under the panel and scans the document
What does OCR software stand forOptical Character Recognition software
What does a OCR do?It allows scanned text to convert into text file format
What are the uses of 2D scanners?Airport to read passport, OCR can change copy text into digital form of password information
When image of person in passport are compared to real life face, how do they examine it?By scanning distance between eye, nose width, shape of cheek bones, length of jawline, shape of eyebrows
What is the definition of a 3D scannerAn input device that scans a solid object and produce a 3D digital image of it
What does a 3D scanner use to scan?It uses tomography
What is the definition of tomographyIt means object are scanned by scanner taking multiple pictures of object with different angle and put them together to form 3D object
What are the 3 rays used in 3D scannerX-ray, radio waves and gamma rays
What type of scanner uses X-rayCT (computerised tomography)
What type of scanner uses radio wavesMRI (magnetic resonance imaging )
What type of scanner uses Gamma RaysSPECT (single photon emission computed tomography )
Scanned image form 3D scanners can be used in?CAD (computer aided degign)
What is the definition of barcode?A series of black and white parallel line of different thickness
Why can a barcode be scanned from any direction?The digit on the left starts with white bar, right hand side stars with black
How can a barcode be readBarcode is read by LED or red laser, white bars reflects light, black bars absorb light, barcode is then read
How can the reflected light by be read form a barcodeIt is read by photoelectric cells, pattern generated and converted to digital data
What are the 3 advantages of barcodesFast and easy to check price or info of product, automatic stock control, reduction of errors
What are the disadvantages of barcodeIf not printed properly or been blocked or tore then it can’t be scanned
How does a barcode scanner in the mall work?1. Barcode is scanned and numbers looked up in stock database 2. When number is found, stock items record look up 3. Details of item shown 4. Number of stock reduced by 1, new value written 5. Number of stock compared to reordered level
What does QR code stand forQuick Response code
What is the definition of QR codeQuick response code is made out of matrix of black squares on white background
What are the difference between barcode and QR codeBarcode can hold up to 30 digits, QR code could hold up to 7000 digit
What are the 3 advantages or QR code?No need to type url, easily scanned, can be displayed everywhere
What are the 2 disadvantages of QR codeCan be easily scam, not as well known
What is the definition of digital camerasA camera which can produce digital image that can be stored in computer
What controls digital cameraMicroprocessor
What are the 6 things that a microprocessor of digital camera can doAutomatically focus on image, auto operate flash, adjust speed of taking photos, adjust aperture size, adjust size of image, remove red eye
How are photograph taken?They are taken when light passes through the lens onto light-sensitive cells which are made of pixels
Why are ergonomic keyboards formed?To prevent RSI
What does RSI stand forRepetitive Strain Injury
What is the definition of keyboardAn input device which is used to input data by pressing a set of keys
What are the advantages of keyboard?Easy to use, keys are letters that humans understand
What is the definition of a pointing deviceA device used to control the moves ment of cursor on computer screen
What is the definition of microphoneAn input device that can input sound into a device
What are the two types of recognition of microphone?Voice and speech recognition
How does a microphone work?When microphone detects sound, a diaphragm vibrates producing on electrical signals, the signal is then transmitted to sound card and converted into digital data
After microphone detects sound, what happens?Diaphragm vibrates producing electrical signals
Where does the signal produced by diaphragm form a microphone go to?It is transmitted to sound card and converted to digital data
What is The difference between Voice recognition speech recognition?Voice recognition detects a person speaking, speech recognition detects the words spoken
How does a voice recognition work?User voice is detected and converted into digital wave pattern, software compared wave pattern with stored wave pattern, if true, person has been correctly identified.
What are the limitation of voice recognitionThey are limited in recognising words and phrases
How does a speech recognition work?When sound is inputted, sound card in device converts sound wave into digital data, software takes digital value and breaks them up into phonemes, phonemes compared with words in dictionary, word spoken will then be suggested and output
After a sound is inputted in speech recognition, what happensthe Sound card in device converts sound wave into digital data
During speech recognition, after sound waves are converted into digital data, what happens?Software breaks digital values down into phonemes, phonemes is compared to dictionary
What is the definition of touchscreen?A device that allows the user to interact with a device by touching areas on the screen
What are the three types of touchscreen?Capacitive, resistive, infra-red
What is capacitive touchscreen made out ofIt is made up of multiple layers of glass, creating electric fields between them
When capacitive touchscreen is touched, what happens?The electric current changes when glass is touched. Then coordination where it is touched is determined by microprocessor
What are the 4 advantages of capacitive touchscreen?Medium cost, good screen visibility, durable screen, multitouch capability
What are the disadvantages of capacitive touchscreenAllows only to touch by finger (not gloves)
What is resistive touchscreen made up of?It’s upper layer is made up of polyester while bottom layer is glass
What happens when resistive touchscreen is touched?When surface (top layer) is touched, it completes circuit with he bottom layer, signals are then send to microprocessor which calculate coordination on where is touched
What is the 2 advantages of resistive touchscreen?Cheap, can use bare fingers, gloves to touch
What are the 3 disadvantages of resistive touchscreen?Poor screen visibility, no multitouch, fair screen durability
What is the definition of interactive whiteboardA device which can display computer image on whiteboard using projector
What are the 3 advantages of interactive whiteboardCan do what computers can do (play games), many can view form big screen, can save data written on board and use further