level reduces artefacts and noise in output
image, but can also result in removing small objects that appear
against a textured background. By default the highest filter level 2
is used.</dd>
<dt>
<code>--denoise</code>=level</dt>
<dd>Set level of wavelet-based denoise filter applied to the result
image. Because focus stacking selects the largest difference from
source images, it has a tendency to increase noise. The denoising
step reduces all wavelet values by this amount, which corresponds
directly to pix