Digital camera part 1

Hmm haven't wrote for the past 2 days... well think today's topic on digital camera should be quite easy for most ppl. As I look through the article, I think there are certainly more than meets the eye...

First, the difference b/n a digital camera and a normal camera. Well, digital camera has a built-in computer which can store images in electronic form rather than rely on chemical and mechanical processes. Instead of focusing light on a film(normal camera), digital camera focuses light onto a semiconductor device. The computer then breaks this electronic info into digital data. Most digi cam use the image sensor known as charge coupled device (CCD). Some low-end cam use complementary metal oxide semiconductor(CMOS) technology.CCD is basically a group of tiny light-sensitive diodes(photosites) which convert photons(light) into electrons(electrical charge). Photosite is sensitive to light, so the brighter the light that hits onto a photosite, the more electrical charge the photosite accumulate.

CCD vs. CMOS Sensors
"Charge is transported across the chip and read at one corner of array. An analog-to-digital converter turns each pixel's value into a digital value. In most CMOS devices, there are several transistors at each pixel that amplify and move the charge using more traditional wires.The CMOS approach is more flexible because each pixel can be read individually. "

• CCD sensors create high quality, low-noise images while CMOS sensors are more prone to noise.
• Light sensitivity of CMOS lower due to the fast that many photons hitting the chip hit the transistor rather than the photodiode.
• CCDs consume as much as 100 times more power than an equivalent CMOS sensor.
• CMOS chips can be fabricated on just about any standard silicon production line, so they tend to be extremely inexpensive compared to CCD sensors.
• CCD sensors have been mass produced for a longer period of time, so they are more mature. They tend to have higher quality pixels, and more of them.

CMOS are less expensive and have a longer battery life than CCD.

The amount of detail a camera captures is called resolution which is measured in pixel. Typical resolutions that you find:

• 256x256 pixels - This is 65,000 total pixels.
  
• 640x480 pixels - This is the low end on most "real" cameras. This resolution is great if you plan to e-mail most of your pictures to friends or post them on a Web site. This is 307,000 total pixels.
  
• 1216x912 pixels - If you are planning to print your images, this is a good resolution. This is a "megapixel" image size -- 1,109,000 total pixels.
  
• 1600x1200 pixels - This is "high resolution." Images taken with this resolution can be printed in larger sizes, such as 8x10 inches, with good results. This is almost 2 million total pixels. You can find cameras today with up to 10.2 million pixels.

There are five ways to capture colours for digital cam.

1. Light is directed to the different sensors by placing a beam splitter in the camera. Picture light entering camera as water flowing through a pipe. Beam splitter would be like dividing an identical amt of water into three diff pipes. Each sensor gets an identical look at the image. Each sensor only responds to one of the primary colors due to the filters.
2. This method is known as spinning disk. Basically, it is to rotate a series of red, blue and green filtersin front of a sensor.

A spinning disk filter

3. Interpolation is to permanently place a filter over each individual photosite. This is the process of looking at the other pixels in the neighborhood of a sensor and making an educated guess.

4. Bayer filter pattern alternates a row of red and green filters with a row of blue and green filters.Only one sensor is required, and all the color information (red, green and blue) is recorded at the same moment. That means the camera can be smaller, cheaper, and useful in a wider variety of situations.

5. "Digital cameras use specialized demosaicing algorithms to convert the mosaic of separate colors into an equally sized mosaic of true colors. The key is that each colored pixel can be used more than once. The true color of a single pixel can be determined by averaging the values from the closest surrounding pixels. "

Diamonds?

Well, i guess for ppl like me who don't even patronise the jewellery shop it's something new. So if you tell me what are the "4 Cs", I would give you a blank stare. What the hell are you talking about???

And the salesperson may tell you they stand for clarity, cut, carat and colour...So what is so great about this carbon thingy? Btw, carbon makes up more than 18% of our body. Diamonds form about 161 km below the Earth's surface, in the molten rock of the Earth's mantle, which provides the right amounts of pressure and heat to transform carbon into a diamond. In order for a diamond to be created, carbon must be placed under at least 435,113 pounds per square inch (psi or 30 kilobars) of pressure at a temperature of at least 400 Celsius.

Now there is this thing about kimberlite pipes which are created when the magma flows through deep fractures in the earth.The eruptions push the diamond, rock and minerals through the mantle and crust.This can happen within a few hours. Btw, the crust is abt 100km thick and mantle is abt 2900 km thick. The magma eventually cooled inside these kimberlite pipes, leaving behind conical veins of kimberlite rock that contain diamonds. Kimberlite is a bluish rock that diamond miners look for when seeking out new diamond deposits.

A diamond ranks a 10 on the Mohs Hardness Scale which is much harder than Quartz and Topaz... Basically, cut refers to how the diamond has been cut and its geometric proportions. Clarity is the measurement of a diamond's flaws, which can rank from flawless to Very very slight, very slight...Well, carat is the weight of diamond. 1 carat is 200 mg.
Color - In referring to transparent diamonds, the color scale runs from D to Z, beginning with Icy White -- the color of the most expensive diamonds -- and ending with a light yellow.

Diamonds were actually not that popular with the American public. The reason why we pay so much is because of the diamond cartel, called De Beers Consolidated Mines, Ltd., which is based in South Africa started advertising and the market was mostly controlled mainly by them."A diamond is forever" sounds so familiar to us. Actually , it was created by the N.W. Ayer advert agency in 1947 which greatly changed the diamond mkt.

"Later ads by De Beers told consumers to hold onto their family's diamond jewelry and to cherish them as heirlooms -- and it worked. This eliminated the aftermarket for diamonds, which further enabled De Beers to control the market. Without people selling their diamonds back to jewelers or to other people, the demand for new diamonds increased. "

"Although we often think of diamonds as being clear, there are also blue, red, black, pale green, pink and violet diamonds. These colored diamonds are the truly rare ones. "

Bits and Bytes

Well, you should have heard about bits and bytes just by coming into contact with them. But what exactly are they and how do they come about?

Computers operate on the base-2 number system(aka binary number system).This is because the system is eay to use. Come on, only 2 digits are used 0 or 1.Bit is actually the abbreviation for Binary digIT. An example to find out what 1011 stand for is this:
1 * 2^3) + (0 * 2^2) + (1 * 2^1) + (1 * 2^0) = 8 + 0 + 2 + 1 = 11
So computers use 1011 to store the digit 11.

We normally see bytes in computer. 1 byte is actually 8 bits. Why is it so? This is like asking why are there 12 eggs in a dozen. So it is just like a common consent. With 8 bits in a byte, you can represent 256 values ranging from 0 to 255:

0 = 00000000
1 = 00000001
2 = 00000010
...254 = 11111110
255 = 11111111

In the ASCII character set, each binary value between 0 and 127 is given a specific character.
Using the eg of "Four score and seven years ago," Notepad would use 1 byte of memory per character (including 1 byte for each space character between the words -- ASCII character 32)

Name Abbr. Size
Kilo K 2^10 = 1,024
Mega M 2^20 = 1,048,576
so 1kb =1024b actually..

Here's an eg of binary math:
010
+ 111
---
1001
To summarize, when u add 0 to 1, you get 1. But when you add 1 to 1 u need to carry over so put 0 first then 1 is added to (0+1:extreme left side). You would get another carry over. Again put 0 first then the left over of 1 is displayed as 1.

Wow, actually this whole thing is so simple... can't believe it :Þ