Tuesday 24 April 2012

JPEG 2000 VS JPEG

Hi all. In today's post, we will put some info about JPEG VS JPEG 2000. This is one of our lab assignment that need to be completed.

JPEG
  • JPEG is also known as Joint Photographic Expert Group. It is created in 1986 by an International Organization for Standardization (ISO) and International Telecommunication Union (ITU). JPEG is a working group which creates the standard for still image compression
  • JPEG usually only utilize lossy compression and JPEG does have a lossy compression engine but it is separate from the lossy engine and it is not used very often.

PROS
  • JPEG codec has low complexity. Picture quality is generally good enough.
  • This is also memory efficient. i.e. good compression allows to reduce the file size.
  • It works very well for “slide-show” movies that have a very low frame rate.
  • Also it has reasonable coding efficiency
CONS
  • Single Resolution & Single Quality
  • No target bit rate
  • Blocking artifacts at low bit rate
  • No lossless capability
  • Poor error resilience
  • No tiling & No regions of interest

JPEG2000
  • JPEG2000 is a fairly new standard which was meant as an update of the wide-spread JPEG image standard.  JPEG2000 offers numerous advantage over the old JPEG standard. 
  • One of the main advantages is that JPEG 2000 offers both lossy and lossless compression in the same file stream.
  • JPEG2000 files can also handle up to 256 channel of information as compared to the current JPEG standard.
PROS
  • Improved coding efficiency
  • Full quality scalability
  • From lossless to lossy at different bit rate
  • Spatial scalability
  • Improved error resilience compared to jpeg
  • Tiling & Region of interests

CONS
  • Requires more in memory compared to JPEG.
  • Requires more computation time


Major Difference Between JPEG - JPEG2000


Now, lets compare the image produced in jpeg and jpeg2000 format:


The images that were compressed using JPEG 2000 are seen from above picture retain a much higher quality.


The above image is the comparison between a 13KB JPEG and a 13KB JPEG 2000, and notice the JPEG's more prominent artifacts, particularly on edges and contiguous area.


 16k jpeg

16k jpeg2000

JPEG 2000 also supports advanced features such as a lossless compression mode, alpha channels and16-bit color

  • JPEG images is created for natural imagery while JPEG2000 images is created for computer generated imaginary
  • When high quality is concern, JPEG2000 proves to be a much better compression tool. 
  • JPEG2000 offer higher compression ratio for lossy compression. 
  • JPEG2000 able to display images at different resolution and size from the same image files while with JPEG, an image files was only able to be displayed a single way with a certain resolution. 



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