CCD (Charge Coupled Devices)
Welcome back friends... Previously we discussed about working of a webcam and I will be discussing the working of a CCD now...
We all love to take pictures of things happening around us.
When we take a picture, all we can see is pretty colors and eye catching light effects. So
the question is what makes the camera to capture stuff like these? There is
very interesting concept behind all these. Every camera has a tiny light
sensitive chip called a CCD chip.
The history:
The CCD was invented in 1969 by Willard S. Boyle and George
E. Smith, two colleagues working at Bell Laboratories. They were trying to
develop a new kind of computer memory, originally called “charge bubble device”
in their notes but what they invented was far more useful for capturing and
storing images in digital form. The science behind CCD is the Photoelectric
effect discovered by Albert Einstein.
What is a CCD?
A CCD chip is a tiny grid light detector used in cameras to capture images. This CCD chip converts the stuff which the lens sees into digital information (a binary string of 0s and 1s) which the computer can store and
manipulate.
A CCD chip is considered as the “electronic eye” of a
digital camera. It is a semiconductor chip made of millions of tiny, light
sensitive squares in a grid pattern. These tiny squares are called as pixels. A
megapixel is millions of pixels. This is why we compare cameras by megapixels.
So this is how a CCD looks like,
The megapixel concept:
A good camera has a CCD with many megapixels. The more the
megapixel the better the photo is. Let’s understand this concept with an
example.
If a camera has 6
megapixels (6 million pixels) then it means, pixels are arranged in grid such
that there are 3000 rows of pixel and 2000 columns of pixels (3000x2000=6
million).
If a camera has 12 megapixels then it means that the pixels
are arranged such that there are 4000 rows and 3000 columns
(4000x3000=12 million)
So if you compare the photos taken by these two cameras you
can see that the 12 megapixel camera gave extra 1000 dots both in rows and
columns.
For those who didn't understand the calculation:
6 megapixel : 3000 rows x 2000 columns
12 megapixel : 4000 rows x 3000 columns
So, there are extra 1000 dots in rows and 1000 dots in columns in a 12 megapixel camera when compared with 6 megapixel camera.
The more the dots the more the details and higher resolution. A single
pixel in CCD is 10 micrometers which is 5 to 10 times smaller than human hair.
How do they work?
Let’s imagine… You are pointing your camera towards a bicycle to
take a picture of it.
This is how it works:
- When you point your camera lens towards the light from the cycle falls on the CCD chip through the camera lens.
- The CCD breaks the picture into individual pixels.
- The CCD measures the amount of light arriving at each pixel and turns the information into digital data (a binary string of 0s and 1s) and stores it in the memory.
In
simple “A CCD converts a picture into binary data”
Each number describes one pixel in image. It describes the
brightness, colors and stuff like that.
Hope this was informative..!! :)
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