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Flaming Star Nebula

by Alejandro Tombolini

Introduction

Image of JohnP publicated in Image Processing Challenges - Uncalibrated integration - Main notes: Create a mask and eliminate hot pixels with MorphologicalTransformation Tool. Date: November 2013

Processing

First a crop using Dynamic Crop Tool to remove the black lines in the borders.

Flaming Star Nebula

For removing hot pixels, first duplicate the image and apply noise reduction to the first layer until they are erased as much as possible trying to not affect the small and weak stars.

Flaming Star Nebula

Divide the image by the image clone were previously applied MultiscaleMedianTransform. Note in the preview that the hot pixels are brighten while the stars are soft.

Flaming Star Nebula

Generate a rangemask on the Image25 selecting only the hot pixels.

Flaming Star Nebula

Apply HistogramTransformation and a Dilation with MorphologicalTransformation tool for increasing the hot pixels.

Flaming Star Nebula

Protecting the image with range mask, apply MorphologicalTransformation until the hot pixels disappear (four times)

Flaming Star Nebula

There are very dark pixels in the dark area in the upper left. To partially correct them, I will make a map with the deringing.
For that, duplicate the image and stretch with AdaptiveStretch and consecutively apply HDRMultiscaleTransform.

Flaming Star Nebula

Apply ATrousWaveletTransform adjusting Dark Deringing to maximum, select "Output deringing maps"

Flaming Star Nebula

Now using the map as mask protecting the image, increase a little the HistogramTransformation. The change is dificult to see in this image, but believe me, that there is a little change.

Flaming Star Nebula

Noise reduction using MultiscaleMedianTransform in layers one and two. Previously duplicate the image and stretch using AdaptiveStretch and use the duplicate as mask protecting high signal areas.

Flaming Star Nebula

Stretch the image transfering the ScreenTransferFunction to the control bar of the HistogramTransformation Tool.

Flaming Star Nebula

Build a starmask.

Flaming Star Nebula

Flaming Star Nebula

Flaming Star Nebula

Flaming Star Nebula

Flaming Star Nebula

Protecting stars with starmask, apply ATrousWaveletTransfor for increasing contrast and noise reduction.

Flaming Star Nebula

Invert the mask and apply MorphologicalTransformation for reduction of the stars.

Flaming Star Nebula

More contrast with CurvesTransformation Tool without using mask.

Flaming Star Nebula

Duplicate the image and use it to protect the nebulae and apply GREYCstoration, carefully adjust of anisotropy to fit the need of the darkest areas.

Flaming Star Nebula

Increase luminosity with HistogramTransformation and protecting the nebula with the previous mask.

Flaming Star Nebula

Finally apply HDRMultiscaleTransformation. (Same mask applied)

Flaming Star Nebula

Final Image.

Flaming Star Nebula

Last Update: 22/03/2014 15:43 UT

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