slmsuite.holography.analysis.image_remove_field
- image_remove_field(images, deviations=1, out=None)[source]
Zeros the field of a stack of images such that moment calculations will succeed. Consider, for example, a small spot on a field with strong background. Moment calculations in this situation will dominantly measure the moments of the background (i.e. the field). This function zeros the image below some threshold. This threshold is set to either the mean plus
deviations
standard deviations, computed uniquely for each image, or the median of each image ifdeviations
isNone
. This is equivalent to background subtraction.- Parameters
images (numpy.ndarray) – A matrix in the style of the output of
take()
, with shape(image_count, h, w)
, where(h, w)
is the width and height of the 2D images andimage_count
is the number of images. A single image is interpreted correctly as(1, h, w)
even if(h, w)
is passed, though the returned image remains shape(h, w)
in that case.deviations (int OR None) – Number of standard deviations above the mean to set the threshold. If
None
, uses the median as the threshold instead. Defaults toNone
.out (numpy.ndarray or None) – The array to place the output data into. Should be the same shape as
images
. This function operates in-place ifout
equalsimages
.
- Returns
out –
images
or a copy ofimages
, with each image background-subtracted.- Return type
numpy.ndarray