Digital Cameras

And Digital Information

How a Camera works

Light passes through the lens

Shutter opens for an instant

Film is exposed to light

Film is developed using chemicals

Analog vs. Digital

Analog Continuous Smooth Gradations Natural capture Mechanical

Digital Values measured Points and positions Binary Code Electrical

Binary Code Bit = "Binary digIT."

Binary Code: Base 2 system, 8 bit 2^0, 2^1,2^3….2^7= 8 bits

The code: 1011 (1 * 2^3) + (0 * 2^2) + (1 * 2^1) + (1 * 2^0)

Conversion = 8 + 0 + 2 + 1 = 11

Bits and Bytes

8 Bits in a Byte 01100111 (Byte)

With 8 bits in a byte, you can represent 256 values ranging from 0 to 255, as shown here:

0 = 00000000

1 = 00000001

2 = 00000010

...

254 = 11111110

255 = 11111111

Bits and Color

This is why we have a 256 color limit in an 8-bit

system

•variation of the voltage applied

•subpixel can range over 256 shades.

•Combining the subpixels produces a possible palette of 16.8 million colors (256 shades of red x 256 shades of green x 256 shades of blue

Digital Camera

Charged Coupling Device Contains array of millions

of pixels Record Light intensity Convert light in to binary

information CCD in Action

http://electronics.howstuffworks.com/digital-camera1.htm

Capturing Color

CCD cells are colorblind Only see in B/W or 1/0

RGB and CMYK filters Allows only one color to pass through

Color Capture http://electronics.howstuffworks.com/digital-camera3.htm

CCDs and Arrays

Color Filtering

Color Filter Array Permanent Filter

pattern placed on each photo site (pixel group)

Interpolation Process of using

neighboring colors to determine the true color of a pixel

Algorithm (compression) http://

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Resolution

Resolution Table http://fred.dsimprove.be/__offSite/pixel/static.php

The overall quality of an image Printed or Digital Standards for each DPI, PPI

printing resolution, in particular the number of individual dots of ink a printer or toner can produce within a linear one-inch space.

DPI & PPI

Dots per Inch measure of printing resolution, in

particular the number of individual dots of ink a printer or toner can produce within a linear one-inch space.

Pixels Per Inch Screen resolution of 1024x768 means

1,024 pixels (dots) horizontally across each of 768 lines (www.answers.com)

x65k or x60 hz Colors or cycles

Pixel Depth & Resolution

Bitmap Graphics

Rectangular grid of pixels Color

The color of each pixel is often consist of colored pixels defined by three bytes RGB

Depth of Color image that stores 24 bits of

color information per pixel (the standard for all displays since around 1995)

1 byte for each color

How Does it Work?

Vector Graphic

based upon vector mathematical equations to represent images in computer graphics

Since the art is made from a series of mathematical formulas it will print very crisp no matter how you resize the art.

File Types & Ratings

TIFF Lossless (uncompressed) Raw Files from Cameras and Scanners 16 bit grayscale as well as 24 bit color capable commonly used file format for scientific images (no

loss of info) Very large files Not compatible with all programs

File Types & Ratings

PNG / PSD portable network graphics No Flattening (preserves layers) lossless compression supports 48-bit color and 16 grayscale, lossless

compression Supports Transparency Compatible with Original Software only

File Types & Ratings

JPEG joint photographic experts group 24-bit color lossy compression technique (discrete cosine

function) Flattened Images (no layers) Does not support Transparency!!! Compatible with all software High quality 319K, medium quality 188K

File Types & Ratings

GIF graphics exchange format Supports Transparency has a 256 color palette limitation small, limited files Compatible with all software

BMP lossless compression only 256 colors Small & simple Compatible with all software

Works Cited

Structure of digital cameras http://www-users.mat.uni.torun.pl/~olka/budowa.html Binary numeral system

http://en.wikipedia.org/wiki/Binary_number#Conversion_to_and_from_other_numeral_systems

www.howstuffworks.com How Digital Cameras work www.howstuffworks.com How Cameras work