The Curtaining Filter removes curtaining effects, which are typical for FIB-SEM image scans. In general, the filter applies a deconvolution to receive two 3D images, one only containing the stripes of the curtaining effect while the other image is the resulting filtered image. To learn more about this filter refer to Fitschen et al. (2017).

The filter includes three Stopping Criteria, and the corresponding values for Tolerance or Iterations, which control the computational time and the quality of the filter results:

• In the Iterations mode, the filter stops after a given number of Iterations.
• With Change Dual, a tolerance value is determined internally. The filter stops iterating upon reaching the given Tolerance.
• In the Change Result mode, the differences in the gray values between the iterations are examined for defining the Tolerance value. This mode requires approx. twice the amount of working memory.

The given Tolerances do not depend on the image size.

The Filter Strength can be increased, to remove heavy stripes, or decreased, to reduce the effect of the Curtaining Filter.

Click Apply to remove Curtaining according to the defined settings.

The example below shows the lines that are typical for FIB-SEM gray value images (left) and known as Curtaining effect. After application of the Curtaining Filter, these lines are completely removed from the original image, enabling a proper image segmentation.