IMAGE BASICS Vector and Raster Images vector images

IMAGE BASICS

Vector and Raster Images vector images - mathematically defined - scale does not affect image quality raster images - consist of a grid of pixel values - scale does affect image quality

Raster Image Types • bitmap • grayscale • true color (RGB color) • indexed color - reduced color - pseudocolor (false color)

Raster Image Types • bitmaps - 1 bit per pixel - pixel is either black or white - grayscale images must be dithered

Bitmaps

Raster Image Types • grayscale - 8 bits per pixel - pixel is a shade of gray represented with a pixel value from 0 to 255 - suitable for black & white photographs - allows for antialising in line drawings

Grayscale Images

Raster Image Types • true color (RGB color) - 24 bits per pixel - pixel is one of over two million colors represented with a pixel value from 0 to 255 for each red, green and blue - suitable for color photographs

True Color Images RED GREEN BLUE

Raster Image Types • reduced color images - 8 bits per pixel - represented with a pixel value from 0 to 255 which is an index into a color table - some loss of color (only 256 total) - more efficient than true color

Reduced Color Images

Raster Image Types • pseudocolor images - 8 bits per pixel - represented with a pixel value from 0 to 255 which is an index into a color table - color not necessarily relevant to image content

Pseudocolor Images