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vdBH 15 Reflection Nebula

by Alejandro Tombolini

Introduction

Image of CEDIC team publicated by Herbert in Gallery in PixInsight Forum - Image with faint nebulosity - Main notes: Reparation of defect lines with CanonBandingReduction Script. Contrast with Adaptive Stretch on masks and special masks to work over the background with faint details and noise reduction. Date: March 2015

Processing

This image is a difficult target to process due that the faint nebulosity is mixed at the level of noise, but was taken on wonderfull skies, so I will try to push details working with masks and give contrast saturating the image.

Open RGB and L images for inspection

vdBH 15 Reflection Nebula

Adjust ScreenTransferFunction for better visualization of the image. Ctrl+Atomic buttom and a adjust Shadows clipping

vdBH 15 Reflection Nebula

CosmeticCorrection in L and RGB images

vdBH 15 Reflection Nebula

vdBH 15 Reflection Nebula

There are dark lines originated in bright stars, the brightest the star the more notorious the line. Using CanonBandingReduction I will try to minimize the big one. I did not try to correct the smallest

vdBH 15 Reflection Nebula

Found the correct settings on CBR to reduce the line, but with residual and worst effects on the rest of the image, then I decided to crop it and correct it separatly

Generate two previews, one of them including the defect and the other with certain superposition over the first in both, L and RGB images.

vdBH 15 Reflection Nebula

Perform identical CBR value to both RBG and L on upper section of the image

vdBH 15 Reflection Nebula

Crop both images to the original size of the image

vdBH 15 Reflection Nebula

Idem for the bottom of the image. Perform the same CBR value to both RBG and L.

vdBH 15 Reflection Nebula

Crop both images to the original size of the image

vdBH 15 Reflection Nebula

Save both RGB_previews and use GradientMergeMosaic to reconstruct RGB image without the dark line

vdBH 15 Reflection Nebula

Save both L_previews and use GradientMergeMosaic to reconstruct the L image without the dark line

vdBH 15 Reflection Nebula

Following the process of RGB image, first apply BackgroundNeutralization

vdBH 15 Reflection Nebula

Color Calibration

vdBH 15 Reflection Nebula

Reparation of the saturated stars cores using RepairedHSVSeparation script

vdBH 15 Reflection Nebula

Before and after of the repaired stars when still linear

vdBH 15 Reflection Nebula

MaskedStretch on the RGB image. Here starts the non linear post processing of the image and is where more easily can be followed different approaches to the final image

vdBH 15 Reflection Nebula

Saturation and color using CurvesTransformation tool

vdBH 15 Reflection Nebula

Noise Reduction in Chrominace using ACDNR tool

vdBH 15 Reflection Nebula

Noise Reduction using k-Sigma Noise Thresholding in MultiscaleLinearTranform tool

vdBH 15 Reflection Nebula

ExponentialTransformation

vdBH 15 Reflection Nebula

Now continue with L image. Use DynamicPSF to find the PSF for deconvolution

vdBH 15 Reflection Nebula

Select the PSF in Deconvolution tool and using StarMask tool generate a starmask to be used protecting stars during deconvolution. Set the correct parameters for Wavelet Regularization to protect the background. See before and after in faint stars.

vdBH 15 Reflection Nebula

MaskedStretch. Here starts the non linear post processing of the image and is where more easily can be followed different approaches to the final image

vdBH 15 Reflection Nebula

Clone L_image and apply AdaptiveStretch to generate a mask with high contrast

vdBH 15 Reflection Nebula

Apply the clone as a mask protecting bright area of the image and use LocalHistogramEqualization to give contrast to the image

vdBH 15 Reflection Nebula

Extract the B channel to be use as mask and protecting bright areas of the image adjust CIE c using Blue channel as Reference in InterChannelCurves

vdBH 15 Reflection Nebula

Before adding L to RGB, clone L_image and apply noise reduction using TGVDenoise and MultiscaleLinearTransform

vdBH 15 Reflection Nebula

Add L To RGB image

vdBH 15 Reflection Nebula

Generate a mask to protect stars and background using PixelMath to subtract the previously created starmask from L image

vdBH 15 Reflection Nebula

Use MultiscaleLinearTransform to noise reduction using k-sigma Noise Thresholding and protecting bright areas increasing Bias in layers of 4,8 and 16 pixels

vdBH 15 Reflection Nebula

Extract _G channel using ChannelExtraction tool to be used as mask protecting the nebulae while decreasing saturation in the background and adjusting a and b channels

vdBH 15 Reflection Nebula

BackgroundNeutralization tool to equalize the values of the background still protecting with _G channel

vdBH 15 Reflection Nebula

SCNR to reduce green cast. Apply without mask

vdBH 15 Reflection Nebula

To recover a more sharp look of the background add more L from the original L (MergeMosaic) but protecting L with the stretched Lmask.

vdBH 15 Reflection Nebula

Generate a mask to work over the background. Extract RGB channels and subtract R-G and B-G from the new image

vdBH 15 Reflection Nebula

vdBH 15 Reflection Nebula

Adjust Cuves protecting the nebula with image40

vdBH 15 Reflection Nebula

Generate a mask to work over the background. Extract RGB channels and subtract B-R and B-G from the new image and finally use RangeSelection tool to generate a range_mask over it

vdBH 15 Reflection Nebula

vdBH 15 Reflection Nebula

vdBH 15 Reflection Nebula

Adjust Cuves protecting the nebula with range_mask

vdBH 15 Reflection Nebula

Create a starmask using StarMask tool to be used with MorphologialTransformation tool

vdBH 15 Reflection Nebula

Use Morphological Selection to noise reduction and reduction of stars protecting with starmask

vdBH 15 Reflection Nebula

Extract L and use it to protect background and apply HDRMultiscaleTrasform to compress the dynamic range of the image

vdBH 15 Reflection Nebula

Over the L image apply RangeSelection tool to generate a rangemask to be used for protection of background and stars while using MultiscaleLinerTransform to give contrast in the small scale bright areas of the nebula, including little stars, increasing Bias in the smallest layers

vdBH 15 Reflection Nebula

Over the L image apply RangeSelection tool to generate a rangemask to be used for protection of stars while using SCNR tool for decreasing the green cast

vdBH 15 Reflection Nebula

Assign Profile to the image

vdBH 15 Reflection Nebula

Increase Saturation protecting the background with L

vdBH 15 Reflection Nebula

Over the previously created starmask apply two MorphologicalTransformation process to expand the area of protection

vdBH 15 Reflection Nebula

With the new mask protecting the background apply ACDNR to Chrominance to reduce the increased chrominance noise from color saturation

vdBH 15 Reflection Nebula

Decrease Blue using SCNR and protecting the nebula with the previously created range_mask

vdBH 15 Reflection Nebula

Rotate the image for publication

vdBH 15 Reflection Nebula

Final Image

vdBH 15 Reflection Nebula

Last Update: 16/03/2015 03:48 UT

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