TEND(1)

💖 tend — diffusion image processing and analysis 💖

okay so bestie, this is tend from the User Commands shelf of the manual. let's get into it 🫶

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✨ NAME ✨

tend — diffusion image processing and analysis. that's the whole vibe. 💅

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✨ SYNOPSIS ✨

tend COMMAND [OPTION]...

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🌸 DESCRIPTION 🌸

tend(1) is a command-line interface to a lot of the stuff inside “ten”, which is a C library for diffusion image processing. and ten? it's one library in the “Teem” collection of libraries. more tea about Teem lives at http://teem.sf.net. and if you want to check out the Teem source yourself, here's literally the command:

svn co https://svn.code.sf.net/p/teem/code/teem/trunk teem

now, real talk for a sec 🥺 — the long-term maintenance of this software depends on funding, and funding depends on being able to document who is using it and for what. so if tend(1) or Ten has helped your research — and yes, that absolutely includes simple one-off experiments and mundane data hacking, no gatekeeping here — the Teem developers would love to know. there are multiple ways to communicate this:

• in your publications, consider adding a line like this in the Acknowledgments:

Data processing performed with the tend tool, part of the Teem
toolkit available at http://teem.sf.net.

• alternatively, please email glk@uchicago.edu and briefly describe how Teem software has helped in your work.
• also please consider joining the teem-users mailing list — it's the primary forum for feedback, questions, and feature requests. 👑

and okay, one more thing: just like unu(1), that other Teem command-line binary, it is often useful to chain together invocations of tend(1) with pipes. here's the iconic example, which estimates tensors from DWIs, takes a slice of the tensor volume, computes the standard RGB colormap of the principal eigenvector, and then quantizes it to an 8-bit PNG:

tend estim -i dwi.nhdr -B kvp -knownB0 true \
 | tend slice -a 2 -p 30 \
 | tend evecrgb -c 0 -a cl2 -gam 1.2 \
 | unu quantize -b 8 -min 0 -max 1 -o z30-rgb.png

the way that pipe chain just works? obsessed. 😭✨

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🎀 OPTIONS 🎀

(no standalone options live here, bestie — the real menu is the commands below. keep scrolling 💖)

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💅 COMMANDS 💅

each of the following has a corresponding man page of its own: for example, tend-about(1) for “tend about”. iykyk 🦋

tend about

information about this program and its use — the lil "hi bestie, here's who i am and how to use me" moment. 💖

tend grads

calculate balanced gradient directions for DWI acquisition. 🧭

tend epireg

register diffusion-weighted echo-planar images.

tend bmat

calculate B-matrix given gradient directions.

tend estim

estimate tensors from a set of DW images. the main character of the pipeline, fr fr. 👑

tend sim

simulate DW images from a tensor field.

tend mfit

estimate models from a set of DW images.

tend mconv

convert from one model to another.

tend msim

simulate DW images from an image of models.

tend make

create DT volume from confidence and eigensystem.

tend avg

average across tensor volumes.

tend helix

generate twisting helical tensor field. it's giving spiral core 🌪️✨

tend sten

calculate structure tensors from a scalar field.

tend glyph

generate postscript or ray-traced renderings of 3D glyphs. so pretty it hurts. 🎨

tend ellipse

generate postscript renderings of 2D glyphs.

tend anplot

graph anisotropy metric in barycentric coords. 📊

tend anvol

apply an anisotropy metric to a DT volume.

tend anscale

scale the anisotropic component of the tensors.

tend anhist

generate barycentric histograms of anisotropy.

tend triple

compute volume of shape triples.

tend tconv

convert between different shape triples.

tend point

describe everything about one sample in a DT volume. yes, everything. 💀

tend slice

slice 3D tensors to get slab/image of 3D/2D tensors. 🔪

tend norm

normalize tensor size.

tend fiber

fiber tractography, from one or more seeds. following the vibes literally. 🧵

tend eval

calculate one or more eigenvalues in a DT volume.

tend evalpow

modify shape by raising eigenvalues to some power.

tend evalclamp

modify shape by clamping eigenvalues in some range.

tend evaladd

modify shape by adding a constant to all eigenvalues.

tend evalmult

modify shape by multiplying eigenvalues by a constant.

tend log

calculates logarithm of the tensor.

tend exp

calculates exp() of the tensor.

tend evec

calculate one or more eigenvectors in a DT volume.

tend evecrgb

make an RGB volume from an eigenvector and an anisotropy. 🌈

tend evq

quantize directions of diffusion.

tend unmf

applies and removes the measurement frame.

tend expand

converts masked non-redundant tensor images to redundant.

tend shrink

converts a 9-value DT volume to a 7-value DT volume.

tend bfit

non-linear least-squares fitting of b-value curves.

tend satin

generate a pretty synthetic DT volume. pretty is literally in the job description. 🎀

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🌟 SEE ALSO 🌟

bestie the whole friend group is here, go say hi: gprobe(1), ilk(1), mrender(1), miter(1), nrrdSanity(1), overrgb(1), puller(1), unu(1), vprobe(1), tend-about(1), tend-anhist(1), tend-anplot(1), tend-anscale(1), tend-anvol(1), tend-avg(1), tend-bfit(1), tend-bmat(1), tend-ellipse(1), tend-epireg(1), tend-estim(1), tend-eval(1), tend-evaladd(1), tend-evalclamp(1), tend-evalmult(1), tend-evalpow(1), tend-evec(1), tend-evecrgb(1), tend-evq(1), tend-exp(1), tend-expand(1), tend-fiber(1), tend-glyph(1), tend-grads(1), tend-helix(1), tend-log(1), tend-make(1), tend-mconv(1), tend-mfit(1), tend-msim(1), tend-norm(1), tend-point(1), tend-satin(1), tend-shrink(1), tend-sim(1), tend-slice(1), tend-sten(1), tend-tconv(1), tend-triple(1), tend-unmf(1). 💜

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and that's the whole page bestie!! this one was TEND(1) — a User Commands moment — and it dropped way back in April 2021. periodt. 💅✨🦋