When sliding through an image dataset in one direction, some scans display a "flickering" in the 2D slices. This is common in FIB-SEM scans, which then require Flickering Correction.

First, choose the Direction in which the flickering occurs: X, Y, or Z.

The Correction Method provides two options: Multiplicative and Additive. Which method should be used depends on the processing applied by the image acquisition device. Scanned image data typically indicates whether the device uses linear or logarithmic processing. If the processing is linear, use the Multiplicative correction method. If the processing is logarithmic, use the Additive correction method.

Click Apply to correct the flickering according to the given settings.

The dataset below is an FIB-SEM image of a cathode provided by Zeiss. Flickering can be observed along the Z-axis. Slices 56 and 57 are shown as examples. Slice 56 is slightly darker than slice 57, and the Z-direction histogram also shows significant variation. After applying Flickering Correction in the Z direction, the brightness of the slices is consistent, and the variations in the histogram are much smaller.

To analyze a scan for flickering, either manually scroll through the slices in the Image Processing dialog or create a video that slices through the structure. In the main GeoDict GUI, select File → Save Video as. Under the 2D tab, find the Back to Front (All Slices) and Front to Back (All Slices) presets. For more information about creating videos with GeoDict, refer to the Create Videos user guide.