# ImageJ Documentation Wiki

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plugin:analysis:density_2d_3d:start

This plugin will compute the density of objects in a image based on distance analysis.

The NbNeighbors parameter will determine the number of closest neighbours to compute from each pixel. The distances are sum weighted using this formula :

`∑ (exp(-dist2i * C)`, with `dist2i` the squared distance to the ith closest point, and `C = 1/(2*σ*σ`).

The parameter radius is assimilated as σ and determines roughly the radius of expansion from the spot centre.

Density computation for the spots in top left, with increasing radius 5, 10 and 15.