When a child reads a book, he adds letter by letter and form words; collects words together and make a sentence; goes through sentence by sentence and completes a page. Similarly, a picture is scanned in computer, TV, etc.,
A picture is divided into number of lines and each line is split up into number of points. A point is called a pixel(picture element). Hence the picture is read pixel by pixel and line by line.
Each pixel has brightness info and colour info. Each pixel's info is converted into electrical signal(voltage) then into digital form(0s and 1s). When the whole picture is converted into electrical form or digital form, it can be stored, manipulated and transmitted using high frequency waves.
Scanning occurs in TV, camera, Computers, CAT scan , photocopier etc,.
Note: In TV. 625 lines are scanned in one picture and 25 pictures are transmitted to the TV in one second. One line is scanned in 64 microsecond.
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