Parameter Reference



This parameter defines the cutoff point that will divide the brain.raw_data into a set of true signal points and background points based on the probability that each point is true signal. The _Probabilties.h5 dataset is generated after running the Ilastik pixel classification workflow described in Signal Normalization. Pixels with a value of 1 are likely to be background. Correspondingly, pixels with a value close to 0 are most likely to be true signal. We have found that a threshold of 0.5 is sufficient to divide true signal from background; however, if your data contains a lot of intermediate background values (0.4-0.7), you may benefit from a smaller threshold, e.g. 0.3.

Recommended: 0.5


This parameter is a list of the form [x,y,z] that specifies the dimensions of the voxel in microns. The data in brain.raw_data is scaled by microns to control for datasets in which the z dimension is larger than the x and y dimensions.

Example: [0.16,0.16,0.21]


This is a deprecated parameter that should always be set to [1,1,1].

Required: [1,1,1]


This parameter serves the same purpose as genthresh; however, it is used exclusively on data used for aligning samples using PCA. This threshold is typically more stringent than genthresh to ensure that any noise in the data does not interfere with the alignment process.

Recommended: 0.25


The radius of the median filter can be tuned to eliminate noisy signal. The typical value for radius is 20, which refers to the number of neighboring points that are considered in the median filter. A smaller value for radius will preserve small variation in signal, while a larger value will cause even more blunting and smoothing of the data.

Recommended: 20


This parameter controls how principle components are reassigned to the typical Cartesian coordinate system (XYZ) that most users are familiar with. It takes the form of an array of length 3 that specifies the index of the component that will be assigned to the X, Y, or Z axis: [x index,y index,z index]. Please note that the index that matches each principle component starts counting at 0, e.g. 1st PC = 0, 2nd PC = 1, and 3rd PC = 2.

For example, if we want to assign the 1st PC to the x axis, the 2nd to the Z axis, and the 3rd to the y axis, the comporder parameter would be [0,2,1].

Example: [0,2,1]


This parameter determines which 2 axes will be used to fit the 2D model. It takes the form of a list of 2 of the 3 dimensions specified as a lowercase string, e.g. 'x','y','z'.

If we wanted to fit a model in the XZ plane, while holding the Y axis constant, the fitdim parameter would be ['x','z'].

Example: ['x','z']


This parameter specifies the degree of the function that will be fit to the data. The default is 2, which specifies a parabolic function. A deg of 1 would fit a linear function.

Default: 2


The infrastructure to support degrees other than 2 is not currently in place. Check here for updates.

Landmark Calculation


This integer specifies the number of divisions along the alpha axis when calculating landmarks. See Selecting anum for guidance on setting this parameter.

Example: 20


This parameter sets the size of each radial wedge in the landmark calculation. The program works in radians so this parameter should be a float that can evenly divide into 2Pi. We have found that Pi/4 (45º) is a biologically appropriate division for our typical structures.

Example: 0.79


This parameter is a list of integers that specifies what percentile should be used to calculate the distribution of points along r.

Example: [50]