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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
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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
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 Binary Code
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 • 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 This is why we have a 256 color limit in an 8-bit system
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
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://electronics.howstuffworks.com/digital-camera4.htm
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. Resolution
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
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
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