======Sharpen3D ====== Map sharpening allows to correct for the contrast loss at high resolution, resulting in better interpretable maps. =====Usage===== Use this module to sharpen and subsequently low-pass filter a 3d map. Sharpening helps in interpreting the map: dependent on resolution of the map domains, secondary structure elements or side-chains will be more clearly defined. Sharpening can be either performed using a standard curve from SAXS data((Gabashvili, I.S., et al. (2001). Solution Structure of the E. coli 70S Ribosome at 11.5 Å Resolution. Cell, 100(5), 537-49.)) ("Do not use custom experimental data"; generally more conservative) or using a reference curve from a custom 3d volume ("Use custom experimental data"), e.g. a theoretical density computed from an atomic model. In the latter case, the pixel size of the reference must be provided. Sharpening also increases the high-resolution noise, which may impede reliable interpretation, in particular in less-well resolved regions of the map. Consequently, homogeneously well-resolved maps may subsequently be filtered in global mode, i.e. every part of the map is low-pass filtered to the same resolution. Heterogeneously resolved maps may be be filtered in local mode, i.e. individual regions are filtered according to the respective local resolution. ===== Process ===== |< 100% 30% >| ^ Parameters ^ Description ^ |Amplitude source - //Simulated SAXS data from ribosome// | Use standard curve for sharpening | | Amplitude source - //Custom experimental data//| Use reference curve from custom 3d volume for sharpening | | -> Experimental sampling | Pixel size of reference 3d volume in Å| | Filtering mode - //global// | Low-pass filter sharpened 3d volume everywhere to the same resolution level | | -> Resolution level | Value for global low-pass filtering in Å| | Filtering mode - //local// | Low-pass filter sub-regions of the 3d volume map according to local resolution | | -> Kernel radius | Edge-length of cubic sub-regions in pixels | | -> Resolution threshold | Lowest resolution to which sub-regions are low-pass filtered | | Filtering mode - //none// | Omit low-pass filtering of resulting sharpened map | | Normalize | Check this box to normalize the sharpened 3d volume to mean 0 and sigma 10. | | Pixel size | Pixel size of the 3d volume to be sharpened. | |< 100% 30% >| ^ Input ^ Description ^ | 3d volume | 3d volume to be sharpened | | //Optional experimental data// | Custom 3d volume to be used as reference for sharpening | | //Resolution levels// | Local resolution values ("Resolution levels" output) from [[:eyes:logics:FourierShellCorrelation]] logic | | //Local resolution map// | Local resolution map ("Fourier shell correlation" output) from [[:eyes:logics:FourierShellCorrelation]] logic | |< 100% 30% >| ^ Output ^ Description ^ | 1d power spec of input | 1d curve showing the rotationally averaged power spectrum of the input 3d volume | | 1d power spec of output | 1d curve showing the rotationally averaged power spectrum of the sharpened 3d volume | | Sharpened 3D | Sharpened and possibly filtered 3d volume | |< 100% 30% >| ^ New/Changed Header Values ^ Description ^ | pixelSize | Pixel size in Å | ===== Additional Information ===== 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.