Sharpen 3D

Map sharpening allows to correct for the contrast loss at high resolution, resulting in better interpretable maps.

Use this module to sharpen a 3d volume for a specific resolution. The amplitudes are corrected based on the x-ray experimental data used in spider. Also, another reference curve given by another 3d volume can be used. For this, the reference sampling rate must be provided. If the target resolution is higher than the provided reference curve’s, the curve is extrapolated in a constant way.

The pixel size of the input “Optional experimental data” [in Angstrom]. If no experimental data input is given, this value is not used.

Check this checkbox to fill the filter image with zeros at indexes that are outside the important diameter. Otherwise the filter image will be filled using constant extrapolation.

Check this checkbox to normalize the corrected 3d volume to mean 0 and sigma 10.

The pixel size of the input “3d volume” [in Angstrom].

Cut off resolution in pixel (from 0 to volume radius). 0 = no cutoff

The target resolution level [in Angstrom]

Provides a reference 3d structure which is used instead of the spider x-ray curve for correction

Provides the 3d volume to be sharpened

1d curve showing the 1d averaged power spectrum of the input 3d volume

1d curve showing the 1d representation of the output “Amplitude filter”.

3d volume that shows the applied sharpening filter image.

Contains the corrected output 3d volume.

• resolutionLevel Resolution where cut off was performed
• pixelSize Pixel size of the volume

This logic is not computationally heavy but needs a lot of RAM for execution. The biggest tested dimensions were 1024x1024x1024 which occupied roughly 12gb of RAM. If not enough RAM is available, this logic will fail to execute.