WBPP Weighted Batch Pre-Processing

PixInsight - Image Post Processing

WBPP - Weighted Batch Preprocessing

updated: 2025-03-10

Purpose	This script will add all the light frames, the flats, the darks and the bias frames, register them, stack them, debayer them and return a single stacked image
Menu	Script 🡺 Batch Processing 🡺 WeightedBatchPreprocessing
Input	Batch of original pre-selected Light frames + master Dark, Flats and Bias frames
Output	integrated picture, file name “*_i.xisf” into sub folder "\_Astro\2021 Astro\20210814 M101\AutoCal\master"
Previous Step	Picture Shooting
Next Step	Picture Post Processing
Tutorial	Weighted Batch Preprocessing - YouTube New WBPP 2.5.0 Release \| PixInsight Forum on 2022-09-09

Notice: image solver capability has been removed from PCC. So before you can run the SPCC Spectrophotometric Color Calibration or PCC - Photometric Color Calibration process you either have to make sure you activated the Astrometric Solution in WBPP or run the Image Solver script (Script > Image Analysis > Image Solver) on the final master light image to update the master file with astrometric data.

Step	Action	Description
1	Set Global Options Optimize dark frames: will work on some DSLRs but probably not on OSC cameras. Make sure to check Up-Bottom FITS for ZWO ASI294 (or final picture will be reversed!)	Figure 1.1
2	Adding Frames (Lights, Bias, Dark etc.) If you want to use Master calibration frames instead of multiple single calibration frames, then make sure the file name of the master files start with "Master". Make sure to check Master frames will be marked with an asterisk, see figure 2.1 on the right To ensure that the master files generated by ASIAIR are recognized as Master Calibration Files by PixInsight and thus supplied with the correct parameters by Weighted Batch Pre-Processor (WPP), the file names for Master Calibration Files are subject to special naming conventions. A correct file name could therefore be : MasterFlat_Stack20_50.0ms_Bin1_2600MC_filter-NoFilter_gain100_20250221_1.6C.xisf and the automatic batch process will be able to treat them as master files. Otherwise, the calibration frames will be ignored during the light frame calibration part of the process with an error message such *** Warning: Cannot integrate less than three frames. !!! Error: Master Flat file was not be generated. When adding light you may also consider adding the manually approved light frames from 1.1 Blink or 1.2 Automatic Selection using Subframe Selector in order to avoid integrating frames with satellite streaks or other artifacts. Note: After loading all light, bias, dark and flat frames once, click to verify that PixInsight has accepted all calibration frames. Flat Frame Filter Problem: If you see a message like this Note: No Master Flat will be used to calibrate the frames. then PixInsight was probably unable to correctly interpret the contents of the calibration frame. although binning, filter, exposure are recognized correctly. Workaround: Flat Frames should also contain the correct filter name in the in the filename. Because color light frames from an ASIAIR OSC camera never contain any filter information, even if a filter has been used. The Master Flat Frames must therefore be renamed and the string _filter-NoFilter must be added somewhere in the filename. They also need to be converted from a .fit to a .xisf file in order to be accepted by the WBPP or FBPP batch pre-processing scripts in PixInsight.	Figure 2.1 Figure 2.2 Figure 2.3
3	Bias Frames Integration Settings Combination: Average Rejection Algorithm: Up to 15 frames: use Sigma Clipping Over 15 frames: use Winsorized Sigma Clipping If you are using Master Bias Frame, the above settings do not apply. In this case use "No Rejection" as rejection algorithm.
4	Dark Frames Integration Settings same settings apply as for Bias Frames
5	Flat Integration Settings same settings apply as for Bias Frames IMPORTANT: Flat Frames should also include the correct filter name in the FITS header. As color light frames from an ASIAIR OSC camera never contain any filter information, they will be treated as NoFilter files and therefore the Flat Frames must have the FITS entry FILTER = NoFilter as well in order to be accepted by the WBPP or FBPP batch pre-processing scripts (see chapter Calibration Frames for more details)
6	Light Frame Handlings Subframe Weighting try the settings on the right Comet processing: WARNING: if you are processing frames of a comet then please make sure not to use the integrated Image Integration. Uncheck the the Image Integration step in case of comet pictures (see top right screenshot). Image integration will be done using the Comet Alignment tool.
6a	Linear Pattern Subtraction
6b	Cosmetic Correction
6c	Subframe Weighting SNR: If this option is checked light frames will be analyzed and weighted accordingly to the relative weights assigned to FWHM, eccentricity and SNR. Weights are saved into the image as WBPPWGHT header key which will be used during the ImageIntegration process.
6d	Image Registration try the settings on the right. Set Pixel Interpolation to Auto or try Lanczos-3, which seems to be a good interpolation algorithm.
6e	Image Integration (Stacking) Rejection Algorithm: Up to 15 frames: use Sigma Clipping Over 15 frames: use Winsorized Sigma Clipping.
7	On the Post-Calibration tab enable Drizzle configuration (always for OSC cameras!) Scale: Drizzle output scale, or subsampling ratio. This is the factor that multiplies input dimensions (width, height) to compute the dimensions in pixels of the output integrated image. For example, to perform a 'drizzle X2' integration, the corresponding drizzle scale is 2 and the output image will have four times the area of the input reference image in square pixels. Drizzle drop shrink factor: This is a reduction factor applied to input image pixels. Smaller input pixels or drops tend to yield sharper results because the integrated image is formed by convolution with a smaller PSF. However, smaller input pixels are more prone to dry (uncovered) output pixels, visible patterns caused by partial sampling, and overall decreased SNR. Low shrink factors require more and better dithered input images. The default drop shrink factor is 0.9.
8	Set the output folder Use subfolder "AutoCal\master" as output directory.
9	Start the batch process by first running a diagnostic check and then the click on Run if the diagnostic didn't return any problems.
10	Check and save the log file for documentation e.g. into a subfolder "logs" and name it according to major process settings, e.g. "AWBP_Lanczos-3_ ProcessLogger.txt"	Example log file
11	Rename the resulting master light image file Typically, PixIsight will use the original filename and put a "master" in front of the name, like: "masterLight_BIN-1_EXPOSURE-180.00s_FILTER-NoFilter_RGB.xisf"	Consider renaming the file to your own file name convention in the master subfolder using the naming convention, e.g.: [DATE_]{TIME_}[OBJECT_][CAMERA_]{ PICTURE #}{-VARIANT#}.[EXT] e.g.: “20210815_M101_ZWOASI294_0000.xisf”