volvis.lb: Show continuous 3D voxel/volume data as a lightbox,...
In fsbrain: Managing and Visualizing Brain Surface Data

volvis.lb

R Documentation

Show continuous 3D voxel/volume data as a lightbox, optionally with a background brain volume and colormap.

Description

This function is the main way to visualize 3D volume images that contain raw MRI scans or statistical results.

Usage

volvis.lb(
  volume,
  background = NULL,
  colFn = viridis::viridis,
  colortable = NULL,
  no_act_source_value = 0,
  bbox_threshold = NULL,
  bbox_of_volume = TRUE,
  ...
)

Arguments

`volume`	numerical 3D array of per-voxel data, typically activation data, a raw MRI image, or a segmentation to show. Can also be a filename if the file can be loaded as such a volume with `read.fs.volume`.
`background`	numerical 3D array or 3D array of color strings, the background volume. Typically a raw brain volume. Dimensions and space must match those of the 'volume' for an array. Can also be a single file name as a character string. Can also be a single color name, like '#FEFEFE' but the string then must start with '#' (color names like 'red' are not allowed, they would be treated as file names). If a color string, be sure to use the `...` parameter to set the same color as `background_color` for the tiles.
`colFn`	a colormap function, passed to `vol.overlay.colors.from.activation` and used as colormap for the 'volume' data. Pass NULL to derive gray-scale values from the raw data (only recommended with single-color backgrounds). Note that the colormap is not used for the the background data (if any), which will be shown in grayscale (unless it is a 3D array of color strings).
`colortable`	optional, only makes sense for categorical 'volume' data like segmentations. If not NULL, a colortable as returned by `read.fs.colortable`, or a character string representing a path to a colortable file (like `"FREESURFER_HOME/FreeSurferColorLUT.txt"]`).
`no_act_source_value`	numerical value, passed to `vol.overlay.colors.from.activation`. Specifies the value which is treated as transparent in the 'volume' parameter data (where you will see the background). If you need more control, e.g., you want to treat one or morge ranges of values as NA, you should load the 'volume' data first, modify it as needed, as pass it to this function afterwards. Set this parameter to `NULL` to disable it. Only for 'colFn', ignored if a 'colortable' is used.
`bbox_threshold`	numerical scalar, passed on to `vol.merge`. If set, voxels with intensities smaller than this threshold will be dropped at the outside of the image. If `bbox_of_volume` parameter is `TRUE` (the default), this threshold applies to the 'volume', otherwise to the 'background'. Set to `NULL` to disable bounding box and show the full image.
`bbox_of_volume`	logical, whether the bounding box is computed on the volume (foreground), which typically is what you want. Leave alone if in doubt.
`...`	extra parameters to be passed to `volvis.lightbox`, can be used to select specific slices, set the `backgroud_color` for the border between and around the image tiles, etc.

Note

This function should be preferred over manually calling volvis.lightbox.

Examples

## Not run: 
volume = subject.volume(subjects_dir, subject_id, 'brain');
volvis.lb(volume);
volvis.lb("~/study1/subject1/mri/brain.mgz");
volvis.lb("~/study1/subject1/mri/brain.mgz", bbox_threshold = 1L);
volvis.lb("~/study1/subject1/mri/brain.mgz", background = "~/data/study1/subject1/mri/T1.mgz");
volvis.lb("~/study1/subject1/mri/brain.mgz", background = "#FEFEFE", background_color="#FEFEFE");
ct = file.path(find.freesurferhome(mustWork = T), "FreeSurferColorLUT.txt"); # ct = "color table"
volvis.lb("~/study1/subject1/mri/aseg.mgz", background="~/study1/subject1/mri/T1.mgz",
 colortable = ct, colFn=NULL, axis=2L);
volvis.lb("~/study1/subject1/mri/aseg.mgz", background = "~/study1/subject1/mri/T1.mgz",
 colortable = ct, colFn=NULL, bbox_threshold = 0);

## End(Not run)

fsbrain documentation built on July 9, 2023, 7:12 p.m.