If I have a 3D array along with a unit normal vector and point for a plane that intersects that array, how would I use Interpolations.jl to create a new 3D array that is the same size as the original array but where all the voxels are interpolated to be perpendicular to that plane? So far I have an …

Meshes.plane uses the first point it’s given as the origin of the resulting plane. If you want a plane centered around a different point, you can apply an offset to each of your points. It’ll be faster to compute the locations on the fly: julia> offset = Point(centroids) - Point(first(pts)) 3-eleme…

[image] Dale_James_Black: a plane that intersects that array, What does it mean for a plane to intersect the array? Do you mean that each entry A[i,j,k] in the array corresponds to a point (x[i],y[j],z[k]) on a grid for a box in space that intersects the plane? [image] Dale_James_Black: …

Good questions. I guess I am thinking more along the lines of multi-planar reformation in medical imaging link Blockquote What does it mean for a plane to intersect the array? Do you mean that each entry A[i,j,k] in the array corresponds to a point (x[i],y[j],z[k]) on a grid for a box in space t…

[image] Dale_James_Black: I don’t think each point in the array corresponds to a point on the plane. I am thinking about some plane at an arbitrary angle that “slices” through the array. Yes, that’s what I said — the array elements corresponds to points on a Cartesian grid and the plane slici…

Blockquote That’s the part that is unclear to me. What are the new values that you want? (My first thought is that you wanted the values in the array interpolated onto a grid in the plane, i.e. for visualizing an arbitrary slice of a 3d array. This seems to be what is happening in the “multiplana…

julia> using Interpolations, Meshes julia> A_itp = linear_interpolation(axes(A), A); julia> plane = Plane(Point(point), Vec(normal)) Plane{Float64}(Point(190.0, 195.0, 7.0), [0.06951752486064443, 0.9975604794114311, -0.006356386842015778], [0.18113406477660973, -0.006356386842015778, 0.98343787141…

Try Images lib: imrotate, imresize

Thank you, that looks like it’s exactly what I am looking for. I will investigate a bit more but for now I will go with this!

Do I need to involve an extrapolate function of some sort? One problem I am running into is bad indexing when I make the locations range larger than -5:5. Or is this just because of the linear interpolation? e.g. r = 6 locations = [plane(i, j) + Meshes.Vec(unit_normal)*k for i in -r:r, j in -r:r, …

You need to define a boundary condition (see here ) - e.g. linear_interpolation(...; extrapolation_bc = 0.0).

Interpolate a 3D array

Specific Domains Signal and Image Processing

rafael.guerra February 1, 2023, 11:01pm 8

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Interpolate a 3D array

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