Usage

The Entropy module makes for a fantastic narrowband manipulaton tool; here it was used to effortlessly boost the prevalence of O-III emissions in a SHO-mapped image.

The Entropy module is very flexible in its image presentation. To start using the Entropy module, an entropy map needs to be generated by clicking the 'Do' button. This map's resolution/accuracy can be chosen by using the 'Resolution' parameter. The 'Medium' resolution is sufficient in most cases.

For the entropy module to be able to identify detail, the dataset should ideally be of an image-filling object or scene.

After obtaining a suitable entropy map, the other parameters can be tweaked in real-time;

The 'Strength' parameter governs the overall strength of the boost or attenuation of luminance. Overdriving the 'Strength' parameter too much may make channel transitions too visible. In this case you may wish to pull back, or increase the 'Midtone Pull Filter' size to achieve a smoother blend.

The 'Dark/Light Enhance' parameter enables you to choose the balance between darkening and brightening of areas in the image. To only brighten the image (for example if you wish to bring out faint H-alpha, but nothing else), set this parameter to 0%/ 100%. To only darken the image (for example to better show a bright DSO core) bring the balance closer to 100%/0%.

The 'Channel Selection' parameter allows you to only target certain channels. For example, if you wish to enhance S-II more visible in a Hubble-palette image, set this parameter to red (to which S-II should be mapped). S-II will now be boosted, and H-alpha and O-III will be pushed back where needed to aid S-II's contrast. If you wish to avoid the other channels being pushed back, simply set the 'Dark/Light Enhance' to 0/100%.

The 'Midtone Pull Filter' and 'Midtone Pull Strength' parameters, assist in keeping any changes in the brightness of your image confined to the area where they are most effective and visible; the midtones. This feature can be turned off by setting 'Midtone Pull Strength' to 0%. When on, the filter selectively accepts or rejects changes to pixels, based on whether they are close to half unity (e.g. neutral gray) or not. This feature works analogous to creating a HDR composite from different exposure times. The transition boundaries between accepted and rejected pixels are smoothened out by increasing the 'Midtone Pull Filter' parameter.