This page describes the UnBlock library. If you are looking for information on JPEG-Clear, then please click here.
UnBlock is a library that removes the "blockiness" of heavily or moderately compressed JPEG images.
Nothing. UnBlock is freeware. See the "MIT"-style license at the end of this page.
Yes: click here.
No. Many software products now offer similar deblocking filters. UnBlock is just my own contribution.
At the time I developed UnBlock (early 2006), the best existing automatic deblocking filter commercially available was from Pegasus Imaging.
Click here to see a "head-to-head" between Pegasus and UnBlock.
The President of Pegasus Imaging publicly stated that UnBlock also out-performed Pegasus’s own patented but unreleased deblocking algorithm.
That depends on whether you want to:
Save the file unblock.exe (256 kB).
The application does not need to be installed. Just run it from where you saved it to.
To "uninstall" the application, just delete the file unblock.exe. The application stores a few settings in the Windows Registry. If you want these to be removed, then run uninstall_unblock.exe.
Save the file unblock_jpeg.exe (232 kB).
Open a Command Prompt, and go to the folder where you stored unblock_jpeg.exe (or add it to your path). If you have a blocky JPEG image called in.jpg, and you want the UnBlocked image to be stored in out.jpg, then type
unblock_jpeg in out
You need to know how to compile a C program to do this. If you don't know what this means, don't ask me.
Save the zip file unblock_source.zip (64 kB) and unzip it.
You also need the Independent JPEG Group (IJG) JPEG library version 6b (27 March 1998) from ijg.org. All required files are in the file ijg.zip (271 kB).
Compile and link all of the .c files to create the executable unblock_jpeg. A sample command line (shell script or batch file) that will do this for the GCC compiler is gcc_unblock_jpeg.
Save the zip file unblock_source.zip (64 kB) and unzip it.
Read at least the first section of unblock_manual.pdf (285 kB).
If you need to understand how the algorithm works, read the scientific paper unblock_paper.pdf (126 kB).
If you want to know how the library code implements the algorithm, read the second section of unblock_manual.pdf (285 kB).
Copyright © 1989–2008 John P. Costella.
Permission is hereby granted, free of charge, to any person obtaining a copy of this webpage and associated software and documentation files (the "Software") to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY CLAIM, DAMAGES, OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT, OR OTHERWISE, ARISING FROM, OUT OF, OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.