Image:
A few details & credits:
You can view all the details and interesting features of the image on astrobin here: https://www.astrobin.com/zzoau6/
Processing workflow:
The processing steps here are a result of an iterative processes where I determined the best methods for this dataset.
Background flattening:
DBE was used to remove the gradients from R, G, B, Ha, and Oiii. Due to flattener issue with the Oiii data, a circular gradient appeared after DBE. This was removed by creating a pseudo-large-scale-MSGR reference using clean Oiii data and then pixelmath division.
Noise reduction:
In order to effectively noise-reduce the image, deepsnr was used. Because this noise reduction algorithm requires an rgb image with independant chrominance profiles, SHO was denoised as one image and RGB was denoised as one image. Further MMT noise reduction was applied to Oiii to remove the mid-scale noise
Other linear processing
I worked quite hard on Luminance to balance the amount of noise reduction and detail that I could bring out. The following steps were used to processes the SHO image in the linear state:
- Deconvolution using the Regularized Van-Cittart algorithm
- BlurX only targeting stars to shrink the stars
- Deepsnr
- MMT noise reduction
- Color balancing
Because the RGB image is only used for color information, there was a strong bias towards reducing chrominance noise. The following steps were used to processes the RGB image in the linear state:
- TGV denoise targeting Chrominance
- DeepSNR with a star mask
- NoiseX with a star mask
- Spectral photometric color calibration fit to a average spiral galaxy
- BlurX only targeting stars to shrink the stars
Non-Linear Processing (SHO)
Below are various states of the SHO image.
1. Pure stretch done with Histogram transformation
2. Color equalization done with histogram transformation and curves transformation
3. Contrast enhancement done with curves and LHE
4. Saturation and color enhacements done with various masks and curves trasnformation
5. Green removal using MMT to even out overall lightness balance
6. Star addition done through relinearazationNon-Linear Processing (SHOO)
Below are various states of the SHOO image. This was processed to be closer to true color while also preserving channel identity. The SHOO image was created by color-calibrating an HOO and SOO image, then adding with equal weights.
1. Pure stretch done with Histogram transformation
2. Blue channle equalization done with histogram transformation and curves transformation
3. Contrast enhancement done with curves and LHE, blue enhancement done with a B-R mask
4. Saturation and color enhacements done with various masks and curves trasnformation
6. Star addition done through relinearazation
One thought on “ A Tapestry of Nebulae and first color image of the pulsar wind nebula around pulsar PSR B1951+32: Processing notes”
You have a unique way of looking at things that’s incredibly helpful.