Sometimes the edges of noise images can have large negative values rather than "blanked" (NaN or 0) pixels which will result in erroneous negative values min_rms.
Fix this by dropping negative pixels in the images before generating statistics on them.
Sometimes the edges of noise images can have large negative values rather than "blanked" (
NaNor0) pixels which will result in erroneous negative valuesmin_rms.Fix this by dropping negative pixels in the images before generating statistics on them.