Immix aligns and merges a set of similar images in order to decrease their noise.
Immix project is available for Linux and Windows.
In a low-light environment, when the flash is not an option (for distance or lighting quality reasons), a digital photographer has the option of either using a low-ISO (low sensibility) setting with a long exposure time, or using a high-ISO setting with a shorter exposure time.
While the former produces high-quality output, the long exposure time involved imposes the use of a tripod (otherwise the image will be blurred).
On the other hand, a high sensibility allows handy exposure times, but at the expense of increased numerical noise - this approach is in fact automatically chosen by most cameras.
The third option consists of taking several pictures of the same scene with a short exposure, then aligning them and merging them to decrease the noise. The signal/noise ratio grows with the square root of the number of images : for example, a combination of 16 ISO 400 images has no more noise than a single ISO 100 image.
The images are loaded into the programme, then automatically aligned using 2 specified reference points (this allows for a small shift, rotation or scaling between images, to be corrected), then merged (average).
The images are aligned by means of a cross correlation algorithm on two zones. These "reference" zones are chosen by the user on the first image. The use of the excellent fftw library allows nearly instantaneous correlation calculation for 200x200 px reference zones (N log N algorithm).
What's New in This Release:
· Image alignment is now threaded, and should use multi-core machines to their full potential.
· Threaded image alignment also means that the UI doesn't freeze anymore.
· A new dialog is shown during alignment, displaying image transformation data.
· A Russian translation was included.
· A Slackware package is now available.
· Icons were added here and there.
· There were various bugfixes, improvements, and optimizations.