Hugin stacker
hugin_stacker stacks overlapping images to a single image.
The general usage is
hugin_stacker [options] --mode=STRING images
There are several stack modes (switch --mode) available:
- min|minimum|darkest: Select the darkest pixel
- max|maximum|brightest: Select the brightest pixel
- avg|average|mean: Calculate the mean for each position
- median: Calculate the median for each position
- winsor: Calculate the Winsor trimmed mean for each position. The parameter can be set with --winsor-trim=NUMBER (default: 0.2)
- sigma: Calculate the sigma clipped mean for each position. Fine-tune with --max-sigma=NUMBER (default: 2) and --max-iterations=NUMBER (default: 5)
This is useful for e.g.
- automatic tourist removal (not only tourists, also other moving objects ;-))
- noise reduction
- visualize movement
- multiplicity
Further parameters
- --output=FILE: Set the filename for the output file (if not given final.tif is used).
- --compression=value: Set the compression of the output files
- For jpeg files use values between 0 and 100
- For tiff files valid values are: PACKBITS, DEFLATE, LZW
Mask input images
Beside the stacked output hugin_stacker can also mask the input images (available only for stacking modes median|winsor|clip). This mode is activated with --mask-input. In this case the stacked image is calculated first. Then each pixel in each image is checked: if the value of this pixel differs more then mask sigma * standard deviation from the mean/median, this pixel is made visible. If it is in the mentioned range the pixel is masked out.
The sigma parameter for this step can be changed with --mask-sigma=NUMBER (default is 2).
You can output a separate mask image for each input image. Set the suffix with --mask-suffix=STRING (default is _mask). Or with the option --multi-layer-output you can output a layered TIFF with the name specified with --output. The file contains the averaged image as layer 0 and all input images as additional layers with the mask as described above.