StarTools Main Window Use

Notes from users, documentation addendums.
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StarTools Main Window Use

Post by Guy »

Here are some notes relating to using StarTools. It is not the only way to use it and experimentation is encouraged.
They relate to StarTools versions 1.7, 1.8 and 1.9
Please let me know if anyone sees any errors or has any additional advice they think helpful.
Many thanks to Ivo for his feedback and tireless support. Thanks also to Jochen for his help with v1.6 and others who have contributed,
I will update this post as needed.
To see a full alphabetical list of module topics click here.

Offline Use
There are a number of ways you can create a copy of these notes for use offline:
  • Print the notes using the browsers print function. The results may vary depending on the browsers used.
  • Create a PDF file using the browsers 'print to PDF' fucntion usually available as an option when printing.
  • Create a PDF file using one of the web page to PDF converters available online.
StarTools' Main Window

  • To load the initial image(s), select modules to apply, change the mask, undo changes, and save the desired result.
Useful Sources
The StarTools Quick-Start Guide is a useful starting point, while the StarTools main online documentation StarTools Modules is also a good source of help. The StarTools Links page has a lot of very useful links.
There is also a Official StarTools English Manual (pdf). It relates to StarTools version 1.6+.
The Unofficial StarTools English Manual (pdf) is a good general source of help. There are versions that relate to StarTools version 1.6 and
version 1.7

When to use:
  • At the start of processing to load the files(s).
  • To select the next module to apply (see below for example workflow).
  • Between modules to set a mask or undo some changes.
  • To turn Tracking off towards the end of the workflow.
See the Quick Start Tutorial for a quick generic workflow.

Full Workflow Example (v1.7):
{Compose}-AutoDev-{Lens}-Bin-Crop-Wipe-AutoDev(or FilmDev)-{Contrast/HDR/Sharp/Decon}-Color-{Shrink/Filter/Entropy/Super Structure}-Unified De-Noise-{Layer/Flux/Repair/Heal/Synth/Stereo 3D}
Key: {...} optional modules

Full Workflow Example (v1.8):
{Compose}-AutoDev-{Lens}-Bin-Crop-Wipe-AutoDev(or FilmDev)-{Contrast/HDR/Sharp/SVDecon}-Color-{Shrink/Filter/Entropy/SuperStr/NBAccent/}-Track/NR(Unified-Denoise)-{Flux/Repair/Heal/Layer/Synth/Stereo 3D}
Key: {...} optional modules

Full Workflow Example (v1.9):
{Compose}-OptiDev-{Lens}-Bin-Crop-Wipe-OptiDev(or FilmDev)-{Contrast/HDR/Sharp/SVDecon}-Color-{Shrink/Filter/Entropy/SuperStr/NBAccent}-Track/NR(Unified-Denoise)-{Flux/Repair/Heal/Layer/Synth}
Key: {...} optional modules

  1. Open a file with the Open button, or combine multiple files with the LRGB button.
  2. In turn, select the modules you want to apply (see above for example workflow).
  3. Turn Track off. Denoise at this stage.
  4. Select any remaining modules required.
  5. Save the desired result.
Description of Controls:

Used to open single monochrome or colour images:
  • StarTools reads FITS, PNG and uncompressed TIFF files.
  • StarTools works best with images that are linear and without preprocessing apart from registration and stacking
  • The image should not have had any stretching, noise reduction, colour balancing or deconvolution.
  • For more information see Background Notes.
  • After loading you are prompted about the image source. This will affect how you open the image in StarTools:
    • If it is a (stacked) RAW image - either monochrome or white-balanced colour - select 'Linear, was not Bayered or is white balanced.
    • If it is a (stacked) RAW colour image that is not white balanced - select 'Linear, was Bayered, is not white balanced'. As of StarTools v1.5.366 standard OSC/DSLR data that is not white balanced uses the Compose mode by default. See the Compose module notes for more details of the Compose mode.
    • If it is a JPEG or video source use 'Modified and not linear'.
Used to merge multiple files such as those representing Luminance and Red, Green, and Blue channels, or those representing the Hubble palette. Also allows creation of synthetic luminance channels, and allows different ways of combining this data, such as LLRGB.
See separate Compose module description for details on how to use it.

Saves the current image:
  • To save as a 16-bit TIFF file use the extension .tiff or .tif
  • To save as a JPEG file use the extension .jpg
  • To save as a 8-bit PNG file use the extension .png (StarTools v1.5+ only)
  • Undoes the effects of the previous module.
For general instructions on using the mask see Mask Module Use.

Turns off tracking and provides and opportunity to do the final Denoise.
Note: Moved to left hand side column in v1.7.
See more in Background Notes below and the StarTools page: Tracking.

Allows us to return to the image at a previous stage in the processing - but with the option, for example, of reverting to Linear data but keeping Deconvolution intact - even though that was done after the global stretch.
  • Original - revert to the original Linear, Binned and Cropped image.
  • Linear, Wiped - revert to the Linear image after being Binned, Cropped and Wiped.
  • Linear, Wiped, Deconvolved - revert to the Linear image after being Binned, Cropped, Wiped, and Deconvolved.
  • Globally Stretched, Wiped, Deconvolved - revert to the image after being Binned, Cropped, Wiped, Globally stretched, and Deconvolved.
The modules are all accessed by clicking the corresponding button to the left of the image area. Click on the module name below to get the description of how to use that module.
  • Lens - Correct for lens defects.
  • Bin - Reduce resolution - improve signal to noise ratio.
  • Crop - Crop image edges - remove stacking artefacts.
  • Wipe (v1.7+) - Remove Gradient, light pollution, vignetting and bias issues (v1.7+).
  • OptiDev (AutoDev) - Automated global stretching (v1.5+).
  • FilmDev (Develop) - Global stretching with more manual control.
  • Contrast - Optimise Local contrast.
  • HDR (v1.8+) - Automated Local Dynamic Range Optimization.
  • HDR (v1.7) - Optimise Localised dynamic range.
  • Sharp (v1.6+) - Noise Aware Sharpen detail (v1.6+)
  • SVDecon (v1.8) - Recover detail from seeing-limited and diffraction-limited data (v1.8).
  • SVDecon (v1.9) - Recover detail from seeing-limited and diffraction-limited data (v1.9).
  • Decon (v1.6,1.7) - Recover detail from seeing-limited and diffraction-limited data (v1.6,1.7).
  • Color - Correct and Adjust Colour.
  • Shrink (v1.7+) - Control star appearance - replaces Magic module.
  • Filter - Manipulate features based on colour.
  • Entropy - Enhance local detail based on colour (v1.5+).
  • Super Structure - Global Light diffraction modelling - replaces Life module. (v1.7+).
  • NBAccent (v1.8+) - Controls the look of accents from narrowband data.
  • Track/NR - Toggle Tracking On/Off & select choice of noise reduction - Denoise (v1.7) or Denoise 2 (v1.7).
  • Track/NR (v1.7.450+) - Toggle Tracking On/Off & option of noise reduction - Unified Denoise (v1.7+).
  • Flux - Automatic feature recognition and manipulation.
  • Repair - Repair star defects.
  • Heal - Remove unwanted features.
  • Synth - Augment or replace stars.
  • Layer - Versatile pixel level manipulation.
  • Rotate - Rotate image.
  • Mirror H - Make mirror image horizontally.
  • Mirror V - Make mirror image vertically.
  • Stereo 3D - Create 3D-like images.
StarTools allows the following hotkeys:
  • Zoom - In +, Out -
  • Open - o
  • Save - s
  • Keep - k
  • Mask - m
  • Before/After - B
  • OK/Done - Enter
  • Back/Cancel/OK - Esc
  • Screenshot - x Saves an image of the current StarTools window named Screenshot-<n>.jpg.
Background Notes:

Index of Special Techniques
The Module Use notes often contain a Special Techniques section.
An index to these can be found here

Preprocessing Images for StarTools
  • StarTools works best with images that are Linear and without preprocessing apart from registration and stacking.
  • No stretching, noise reduction, colour balancing or deconvolution.
  • When stacking, use median or some form of sigma clipping with more than 10 sub-frames.
  • Check out the StarTools web page General Preprocessing do's and dont's for further guidance on how to prepare your data for StarTools.
  • Check out StarTools Links and Tutorials for links to advice on using a number of popular preprocessing tools.
  • If using DeepSkyStacker (DSS):
    See also Deep Sky Stacker Settings
    • In 'Register Checked Pictures...' - 'Stacking parameters...' button:
      • 'Light' tab: Change calibration from 'Per Channel Color Calibration' or 'RGB Channels Calibration' to 'No Background Calibration'.
      • 'Result' tab: Uncheck 'Align RGB Channels in Final Image'.
    • In Options - Settings... - 'RAW/FITS DDP Settings...' - 'RAW Files' tab:
      • Check 'No White Balance Processing' (DSS v4.2.3.beta & later)
      • Uncheck 'Use Auto White Balance'. (DSS v4.2.2 and earlier)
      • Uncheck 'Use Camera White Balance'.
      • Select 'Bilinear Interpolation' usually.
      • Uncheck 'Set black point to 0'.
    • When saving the stacked image - in the save dialog choose:
      • Save as type: 'TIFF Image' or 'FITS image', '16 bit/ch' or '32 bit/ch - integer' (a 32-bit file is twice the size of a 16-bit file).
      • Compression:'None' and Options:'Embed adjustments...' - otherwise you will have problems processing using StarTools.
    • For other settings see the topic DSS settings for StarTools.
    • DSS before v4.2.3 always white balanced - unless you preprocess with DCRAW using this method: Eliminating white balancing when using DSS.
    • DSS v4.2.3 Beta and later now includes the option 'No White Balance Processing'
  • If using Regim:
  • If using ASTAP (Astrometric STAcking Program):
  • If using APP(Astro Pixel Processor):
  • If using PixInsight:
    • Rejection algorithm: Sigma clipping or Winsorized Sigma Clipping.
    • No white balance. Don't use BackgroundNeutralization or ColorCalibration processes.
    • Save as:- TIFF: 16-bit, or FITS: either 16-bit unsigned integer or 32-bit unsigned integer.
    • StarTools can take over before you use DynamicCrop or DynamicBackgroundExtension (DBE) processes. See the topic Welcome, Pixinsight Users! for advice on how to use StarTools as an alternative to PixInsight for post-processing.
  • If using Nebulosity:
    • Align and Combine: Standard Deviation based stacking: Sigma-clip.
    • Don't do post processing such as Digital Development, Adjust Color Background or Auto Color Balance.
    • Edit menu - Preferences:
      - 'Save as compressed FITS' - unticked,
      - 'Save in 32-bit floating point' - unticked,
      - 'Scale to 15 bit (0-32767) at Save' - unticked.
      - 'Color File Format' - 'RGB Fits: Maxim'
      - 'Manually Override color reconstruction' - Tick -stops white balancing - set Manual Demosaic Setup.
      - 'Demosaic (Debayer) method' - Bilinear.
    • Save as:- TIFF: uncompressed 16-bit (File - Save 16 bit/color TIFF File), or FITS: uncompressed 16-bit integer (File - Save Current File).
  • If using MaximDL:
    During the Stack process:
    • Color tab: Use Defaults (1:1:1) colour balance, Don't do post processing such as 'Auto equalize background'.
    • Combine tab: Combine Method: Sigma-clip.
    • Save as:- TIFF: uncompressed 16-bit, or FITS: uncompressed, either 16-bit int or 32-bit int.
Tracking in StarTools is the name given to the way in which StarTools gathers information about the signal and its evolution through different modules.
It provides each module with as much information as possible to allow it to get the best results.
Each module can:
  • Understand how each pixel has been modified by previous modules.
  • Influence data earlier in the processing chain (e.g. linear data) and re-apply the modifications made since then.
  • Use the information gained from previous modules to understand how the signal has been changed and where the noise is.
Some benefits of Tracking:
  • Deconvolution only works on linear data - but the Decon Module is used after the data has been stretched.
  • With the Decon module we use it after stretching and processing the data but apply deconvolution on the linear data and watch its effect on the processed image.
  • Noise reduction is applied at the end of processing where Tracking has gained the most information about noise.
  • This means Noise reduction can be automatically targeted most at the areas where it is needed.
StarTools Log File
Every time you process an image, the processing steps are saved to a log file named StarTools.log in the StarTools program folder.
It contains entries for:
  • StarTools version used.
  • Date processed.
  • Source file name and location.
  • Modules used along with the associated parameter values.
  • Saved file name and location.
  • Masks stored encoded as a BASE64 PNG image.
It is very useful if you want to recreate a processing workflow or to help with troubleshooting.
For versions earlier than v1.3.5 it was saved in the folder where the source image file is located.

Setting Startools Special modes & features
StarTools has a number of special modes which can be set.
In version 1.9 each mode is set in the 'config' file.
In StarTools versions before version 1.9, each mode is enabled by creating a file with the name shown below (case sensitive, with no extension if none shown) in same folder as the StarTools executable:
  • Select Language (English, German or Spanish) (1.9 only)
    - 1.9 Config Section [UI Settings], ui_language= (english|deutsch|esp)
  • Stop Mask blinking 3 times as a reminder it is set:
    - 1.8- File: noblink, file contents ignored
    - 1.9 Config Section [UI Settings], ui_reduceblink= (true|false)
  • Make StarTools buttons etc. bigger - for cases where the screen has a high DPI:
    - 1.8 File: highdpi, file contents ignored
    - 1.9 Config Section [UI Settings], ui_highdpi= (true|false)
  • Make StarTools buttons etc. bigger:
    - 1.8 File: largeui, file contents ignored
    - 1.9 Config Section [UI Settings], ui_large= (true|false)
  • Override default OpenCL device selection:
    - For use in the StarTools GPU version to manually select the device for systems with multiple devices from same vendor
    - Putting 0 will force StarTools to use the "0th" device it finds, which should be your iGPU
    - 1.8 File: opencldeviceindex.cfg, Put 0 or 1 in file
    - 1.9 Config Section [GPU Acceleration Settings], opencl_deviceindex= (default|0|1)
  • Override default OpenCL vendor selection:
    - For use in the StarTools GPU version to manually select platform/vendor/driver on systems with multi-vendor GPUs
    - 1.8 File: openclplatformindex.cfg, Put 0 or 1 in file
    - 1.9 Config Section [GPU Acceleration Settings], opencl_platformindex= (default|0|1)
  • Force selection of CPU not GPU:
    - For use in the StarTools GPU version when there is misbehaving OpenCL GPU hardware/drivers
    - On the bottom of the splash screen at startup it shows whether it is using your CPU and GPU, or just the CPU
    - 1.8 File: openclforcecpu.cfg, file contents ignored
    - 1.9 Config Section [GPU Acceleration Settings], opencl_forcecpu= (true|false)
The importance of not White Balancing (Color balancing) when preprocessing.
With White Balanced (Color Balanced) images the R, G and B channels are scaled differently:
  • This makes it impossible to derive an accurate luminance channel for the separate processing of luminance and colour data.
  • Noise levels are changed - Noise cannot be tracked as accurately.
  • Scaling of R,G and B can cause clipping - impacting the ability to extract detail in the highlights.
File formats for Preprocessed files:
Notes on the choice of file format and bit-depth when saving files after preprocessing:
  • To avoid any possible loss of data it is best to save as 32-bit Integer FITS if you have the memory/processing power/disk space. See the topic 'DSS save as choice'.
  • However, most of the time you will not notice the difference if you save as 16-bit TIFF/FITS.
  • Most applications will use the output from StarTools and not the preprocessed output. StarTools output is 16-bit TIFF (or JPEG).
  • If you want to use the preprocessed output with applications other than StarTools - choose TIFF or FITS depending the applications you use.
    - FITS is standard for astronomical applications. It can be read by Startools, PixInsight and FITS Liberator but not MS Windows' own apps. and Photoshop requires a Plug-in.
    - TIFF files (uncompressed) can be viewed by MS Windows' own apps, StarTools, PixInsight and PhotoShop (but see below).
  • Saving as 32-bit may capture a little more detail than 16-bit in some cases but further post processing ( StarTools) takes more processing power and memory, and the files are up to double the size.
  • If using 32-bit - choose 32-bit integer over 32-bit rational unless it is not supported by one of the applications you need to use (see below).
  • The file formats read by common applications are as follows:
    - StarTools uses 64-bit integer arithmetic internally - using integer avoids mapping issues.
    - StarTools and PixInsight read 16-bit, 32-bit integer and 32-bit rational files.
    - FITS Liberator reads 16-bit, 32-bit integer and 32-bit rational FITS format files.
    - PhotoShop does not read 32-bit integer files.
    - Nebulosity does not read 32-bit TIFF or 32-bit integer FITS files.
  • Any intermediate preprocessed files are normally stored as 32-bit - don't change this.
Debayering/Interpolation methods
A brief summary of major methods:
  • Nearest neighbour - uses value of nearest pixel.
  • Bi-linear interpolation - average of the 4 nearest diagonal pixels of same colour (R,G or B) - a good choice if there is noise. For StarTools this is the best choice as it allows StarTools to do better noise control.
  • VNG - Variable Number of Gradients - noise in each frame can cause the VNG algorithm to introduce artefacts and 'bleeds' the noise to surrounding pixels as described in the topic 'Using debayered integrated images'. This method limits StarTools' noise control.
  • PPG - Patterned Pixel Grouping - fewer artefacts than VNG.
  • AHD - Adaptive Homogeneity-Directed - causes artefacts especially if there is noise. Don't use unless the subs have a high SNR. This method limits StarTools' noise control.
  • Bi-cubic interpolation - uses 16 neighbour pixels of the same colour.
If you are unsure which to choose - select bi-linear interpolation if available.

External References:
Comparison of Demosaicing Algorithms
Good Interpolation Introduction

Debayering Artefacts
Artefacts are caused by errors in estimating the 'missing' colours.
Look out for the following effects in debayered colour images:
  • Zipper effect - at edges.
  • False Colour - usually at edges - fringing.
  • Halo - at edges.
  • Aliasing - interference pattern.
  • Mazing - fine parallel lines confuse demosaic algorithm producing an effect that looks like a rectangular maze.
  • Blurring.
Ref: Examples Example 1: Maze, Example 3: Moire interference pattern.
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