Commonly Used Image File Formats

  • 237 views
Uploaded on

basic information about image files and why we use lots of kinds image file formats. …

basic information about image files and why we use lots of kinds image file formats.
Some key terms like pixels, pixel depths, resolution, monochore, grayscale and colored images which will be used in the next sections of the presentation.
Basic compression methods which are used in image compression and give information about lossy/lossles images.
JPEG, PNG, GIF and BMP detailed

  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
    Be the first to like this
No Downloads

Views

Total Views
237
On Slideshare
0
From Embeds
0
Number of Embeds
1

Actions

Shares
Downloads
25
Comments
0
Likes
0

Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide

Transcript

  • 1. Fatih Özlü Image File Formats
  • 2. Content  Introduction to Image File Formats  Image FileTypes (Bitmap/Vector)  KeyTerms for Images  Pixels  Pixel Depth  Compression Methods: Lossy-Lossless  Common Image File formats  JPEG  PNG  GIF  BMP  Conclusion
  • 3. Why so many Image File Formats? … - BMP – PBM – TGA – TIFF – GIF – JPEG – PSD – DXF – CGM – PNG – SVG – RAW – WPG – FITS –PCX– PCD – RAS – TGA – BPS – EPS – PDF – PCT – WBM – FITS – XBM – VFF – RIB – PCX – DMP – AVS – IMG – ICO – JFIF – IFF –WMF - …
  • 4. Image File Types  Bitmap(Raster) images:  collection of dots  each pixel can hold 1,8,24,… bit of color information  fixed resolution  best for photographic quality images, for printing, scanners, digital cameras  examples: bmp, gif, png, jpeg, tiff, …  Vector graphics:  based on mathematical instructions  basically defined by shapes and lines  not resolution dependent: infinitely scalable  examples: svg, ai, wmf, …  Metafile graphics:  combination of bitmap and vector
  • 5. Pixels  image elements  smallest addressable part of the screen  stored as a binary code representing a color  between 1 and 32 bits of binary code  RGB (Red, Green Blue)  CMYK (Cyan, Magenta,Yellow, Black)  resolution  density of dots on image  measured in DPI (dots per Inch)
  • 6. Pixel Depth Images retrieved from http://en.wikipedia.org/  number of bits to store each pixel  greater depth, more colors  greater depth, bigger file size  monochrome : 1 bit(white and black)  grayscale, 16, 256 color  truecolor: 24 bit 1 bit 2 bit 4 bit 8 bit 24 bit
  • 7. Compression  large amount of data  lossy/lossless  quality  Some algorithms  LZW(Lemple-Zif –Welch)Algorithm  RLEAlgorithm  ZIP Compression  JPEG Compression -> lossy  Deflation – used in PNG, MNG, andTIFF
  • 8. JPEG (Joint Photographic Experts Group)  most applications and browsers, digital cameras  good compression algorithm : reduce file size in a ratio between 10:1 and 20:1.  degree of compression is adjustable  lossy compression  not support transparent color  not interlaced:???  extensions: .jpeg, .jpe, .jpg, .jif, .jfif, .jfi Higher quality (Q = 100) High quality (Q = 50) Medium quality (Q = 25) Low quality (Q = 10) Lowest quality (Q = 1) 83,261 bytes 15,138 bytes 9,553 bytes 4,787 bytes 1,523 bytes the uncompressed 24-bit RGB bitmap image below 313 × 234 image (73,242 pixels) would require 219,726 bytes
  • 9. GIF (Graphics Interchange Format)  most widely used  few colors: 8 bit or less  LZW lossless compression algorithm  less space, less loading time  interlaced and non-interlaced  supports animation: can contain more than one image  LZW algorithm patent issue resulted PNG.
  • 10. PNG (Portable Network Graphics)  developed due to legal problems with compression algorithm  PNG's Not GIF  new format targeted for Internet use, becoming common  lossless compression (more than GIF, less than JPEG)  24-bit RGB, 32-bit RGBA or up to 48 bit color  transparency (A:Alpha channel)  no animation support  better interlacing: Adam7 algorithm Illustration of the 7 passes of the Adam7 algorithm, running over a 16×16 image
  • 11. BMP (Bitmap Image File)  Microsoft native image format  Windows,OS/2, no MAC compatibility.  backgrounds, graphics, wallpaper  1(monochrome), 4, 8, 24-bit RGB  generally uncompressed, too large size  lossless RLE compression
  • 12. Conclusion  compression  larger file, larger storage and slower download  few color, smaller file, worse quality  There is really no reason to ever use this format BMP  GIF and JPG are the formats used for nearly all web images. PNG is supported by most of the latest generation browsers.  But Microsoft Internet Explorer does not support PNG transparency.  PNG does everything GIF does, and better, so expect to see PNG replace GIF in the future. PNG will not replace JPG, since JPG is capable of much greater compression of photographic images, even when set for quite minimal loss of quality
  • 13. Thanks  Questions?