Multimedia Technology Image Technology Krich Sintanakul Multimedia and Hypermedia

Technology Multimedia Types of Images Raster Image –Digitize or sampling from the real world –Store in bitmap orientation –Need large storage and High compression –Edit by retouching tool Vector Image –Synthesized image –Store in object structure list (Smaller) –Reusable, Scalable, Animating –No stair problem

Technology Multimedia Types of Images Raster Image

Technology Multimedia Types of Images Vector Image (x min,y min ) (x max,y max ) Object Rectan01 Pivot center Data (x min,y min,x max,y max ) Rectangular (x min,y min,x max,y max ) begin lineto (x min,y min,x max,y min ) lineto (x max,y min,x max,y max ) lineto (x min,y min,x min,y max ) lineto (x min,y max,x max,y max ) end end object

Technology Multimedia Types of Images From vector to raster display system

Technology Multimedia Displaying Image in Computer Cathode-Ray Tubes and LCD panel

Technology Multimedia Displaying Image in Computer Source of color

Technology Multimedia Displaying Image in Computer Source of color in CRT

Technology Multimedia Displaying Image in Computer Color Mixing in RGB model

Technology Multimedia Displaying Image in Computer Raster scan display system

Technology Multimedia Displaying Image in Computer Raster scan display system

Technology Multimedia Displaying Image in Computer Color Raster scan display system

Technology Multimedia Displaying Image in Computer Raster scan display system

Technology Multimedia Type of color display system True Color system –24/16 Bits each pixel –3/2 Bytes per pixel –Keep Color intensity in Frame buffer Index Color system –8 bits (1 byte) per pixel –Display 256 from index table at a time –Keep address of table in Frame buffer

Technology Multimedia Type of color display system True Color system N M Bit depth Video controller CRT

Technology Multimedia Type of color display system True Color system –VGA 24 Bits 640*480 = Pixels = Bytes –VGA 16 Bits 640*480 = Pixels = Bytes –SVGA 24 Bits 800*600 = Pixels = Bytes –SVGA 16 Bits 800*600 = Pixels = Bytes 1 Byte

Technology Multimedia Type of color display system Index Color system x y Color Table R GB colors x 8 bits/column = 24 bits D/A y x 8 bits Frame Buffer

Technology Multimedia Type of color display system Index color system –VGA 256 Color 640*480 = Pixels = Bytes Index table 256*3 (24 bits) 768 Bytes Total = Bytes –SVGA 256 Color 800*600 = Pixels = Bytes Index table 256*3 (24 bits) 768 Bytes Total = Bytes –SVGA 256 Color 1024*768 = Pixels = Bytes Index table 256*3 (24 bits) 768 Bytes Total = Bytes

Technology Multimedia How to display an image file(1) BMP indexed file structure

Technology Multimedia How to display an image file(2) Step 1 Load image information

Technology Multimedia How to display an image file(3) Step 2 Load color index to video pallet

Technology Multimedia How to display an image file(4) Step 3 Load pixel information by lookup color pallet