View Issue Details
|ID||Project||Category||View Status||Date Submitted||Last Update|
|0000101||Siril||[All Projects] Siril||public||2016-01-22 11:19||2017-03-08 16:42|
|Platform||GNU/Linux 64bits||OS||Debian||OS Version||Testing|
|Target Version||1.0.0||Fixed in Version|
|Summary||0000101: Background extraction result needs to be expressed in 32 floating bits|
|Description||Since we have implemented the background extraction module, calculation are done in 32bits integer format. However, the result is stored in a fits structure before applying the correction.|
The fits structure is in 16bit. In consequences, information is lost.
A background model image is an extremely smooth function that usually requires a 32-bit format to be represented correctly and in some cases 16-bit is clearly not enough, leading to a posterized image.
In fact, the background model should be generated in 32-bit integer or 64-bit floating point format because sometimes it is exceeding the range of 32-bit floating point.
|Tags||No tags attached.|
m51bug.jpg (1,633,902 bytes)
||We should find a workaround by using OPENCV to handle temporary images ....|
Wouldn't it be possible to create a virtual background image?
Instead of creating a temporary bitmap, one would create an object that just stores the background formula (polynom?) and calculates pixel values on demand, with whatever precision needed.
Your suggestion matches with previous comment. However changes to do that are a bit tricky. On the other hand, a new library will be implemented for handling 32 and 64bit precisions.
I would suggest you, to workaround this bug, to stretch your image a bit with "Histogram transformation" tool. Indeed, by doing this you enhance dynamic and 16bit is not a problem anymore.
|2016-01-22 11:19||lock42||New Issue|
|2016-01-22 11:19||lock42||Status||new => assigned|
|2016-01-22 11:19||lock42||Assigned To||=> lock42|
|2016-01-22 11:27||lock42||File Added: m51bug.jpg|
|2016-01-22 11:31||lock42||Description Updated||View Revisions|
|2016-01-27 11:11||vinvin||Relationship added||child of 0000103|
|2016-01-27 11:20||lock42||Target Version||0.9.2 => 1.0.0|
|2016-09-27 16:07||lock42||Note Added: 0000357|
|2016-12-19 16:32||lock42||Category||General => Software Development|
|2016-12-19 16:50||lock42||Category||Software Development => Software|
|2016-12-19 23:30||lock42||Category||Software => Siril|
|2017-03-08 16:34||steffens||Note Added: 0000367|
|2017-03-08 16:42||lock42||Note Added: 0000368|