mikro
The Python client for mikro, the Arkitekt service for microscopy and
imaging data. mikro-server is a GraphQL server that keeps the metadata of your data (datasets,
folders, coordinate systems, scenes, and the relations between them), while the pixels live in
object storage as Zarr (and tables as Parquet). This client gives you both as
one: typed, validated Python objects built on rath and pydantic,
whose .data is a lazy xarray backed by dask. When you pass an array to a
mutation, mikro uploads it before the call runs, and when you read one back it downloads only the
chunks you touch.
Installation
pip install mikro
mikro requires Python 3.11+. Extras bring in the heavier wire formats only when you need them:
| Extra | Brings in |
|---|---|
table |
pyarrow, pandas and duckdb, for querying Parquet-backed tables |
mesh |
fabriks, for uploading meshes |
network |
konnektion, for uploading graphs |
sparse |
sporadik, for sparse datasets |
complete |
all of the above |
Inside an arkitekt app, pip install "arkitekt[rekuest,mikro]" installs mikro along with arkitekt and the runtime run(app) needs.
Usage
Every mikro operation is a method of the Mikro client. Each comes in a blocking and an
a-prefixed async flavour (mikro.create_folder(...), await mikro.acreate_folder(...)). An object
that a call returns remembers the client that fetched it, so later calls on it, such as .data, go
through the same client.
In an arkitekt app
Add mikro_service to your app and take the client by annotation. arkitekt injects it. Types from
mikro.arkitekt.specs such as Volume or Image are lenses over a mikro dataset. Each one declares
what an action needs, and the UI then offers only datasets that fit. A run tests the same on every
lens an action takes or returns: one that does not fit the type fails the task, saying why.
from arkitekt import App, Task, run
from mikro import Mikro, mikro_service
from mikro.arkitekt.specs import Volume
app = App("clip-volume", "0.1.0", services=[mikro_service])
@app.action
def clip(volume: Volume, mikro: Mikro, task: Task) -> Volume:
"""Clip Volume
Clips negative values and stores the result on the same grid.
"""
source = volume.data # a lazy xarray.DataArray
task.progress(30, f"Processing {source.shape}")
clipped = source.clip(min=0).compute()
result = mikro.create_array_dataset(
data=clipped,
scales=[],
name="clipped",
axes=volume.carried_axes(clipped.dims),
derived_from=[volume.derive_identity(value_relation="TRANSFORMED")],
)
return result.lens()
if __name__ == "__main__":
run(app)
Datasets, tables, meshes, annotations, lenses, coordinate systems, scenes, folders and files travel
between actions by id (@mikro/arraydataset, @mikro/arraylens for an array lens, @mikro/tablelens,
@mikro/scene, ...), so an action can take them and return them directly.
From a script
easy connects for you and returns the client:
import numpy as np
import xarray as xr
from arkitekt import easy
from mikro import dataset_arrays, mikro_service
volume = xr.DataArray(np.random.random((2, 10, 256, 256)), dims=("c", "z", "y", "x"))
with easy("my-script", mikro_service) as mikro:
folder = mikro.create_folder(name="examples")
# `data` is level 0; `scales` holds only the coarser levels
level_zero, scales = dataset_arrays(volume, levels=3)
dataset = mikro.create_array_dataset(
data=level_zero,
scales=scales,
name="random volume",
axes=["c", "z", "y", "x"],
folder=folder.id,
)
again = mikro.get_array_dataset(dataset.id)
peak = again.data.max().compute() # downloads only what it needs
Use async with aeasy(...) in async code, or interactive("notebook", mikro_service) in Jupyter.
Inside an async loop, remember that computing .data downloads the data in a blocking way on that
loop.
Declared axes are checked against the array before it is uploaded. For example, a rank mismatch
or a missing declaration raises ArrayDeclarationError (tables and sparse datasets have their own
errors) before any data is sent.
A camera frame, and tiles that sit side by side
A frame straight off a camera is a bare array. Three things make it an image someone can look at: labelled axes, contrast limits to draw it with, and a place in physical space.
import numpy as np
import xarray as xr
from mikro import Unit, canonical, dataset_arrays, space_2d
from mikro.api.schema import CoordinateAnchorInput, ScenePolicyInput
def upload(mikro, frame: np.ndarray, name: str, space, x_um: float, y_um: float, pixel_um: float):
# 1. Name the axes. `canonical` puts them in the order the server wants (c, y, x).
image = canonical(xr.DataArray(frame, dims=("y", "x", "c")[: frame.ndim]))
# 2. A pyramid, so a large frame opens at once, and one contrast anchor per channel.
levels = max(1, min(4, int(np.log2(max(frame.shape[:2]) / 512)) + 1))
level_zero, scales = dataset_arrays(image, levels=levels, method="mean")
dataset = mikro.create_array_dataset(
data=level_zero,
scales=scales,
name=name,
axes=[str(d) for d in image.dims],
anchors=CoordinateAnchorInput.histogram_anchors(image),
)
# 3. Where it is: pixel size as the scale, the stage position as the offset.
space.register(dataset, scale={"y": pixel_um, "x": pixel_um}, x=x_um, y=y_um)
return dataset
space = space_2d(mikro, "tile scan", unit=Unit("micrometer"))
for x_um, y_um, frame in tiles:
upload(mikro, frame, f"tile {x_um:.0f} {y_um:.0f}", space, x_um, y_um, pixel_um=0.65)
# One scene over the space: every tile at its position.
space.stage(name="tile scan", policy=ScenePolicyInput(nchildren=len(tiles)))
Units and positions never go on the dataset: a physical space is a coordinate system of its own, and
register says where the data sits in it. Tiles registered into one space share one world, which is
what makes a viewer show them stitched by position. A single frame gets a space of its own the same
way.
stage() builds a scene from at most nchildren registered sources, 8 unless you say otherwise.
A scan of more tiles than that needs the policy above, or the scene silently shows the first eight.
An action that returns the image returns a lens, not the dataset: return dataset.lens().
Working with data
data = dataset.data # level 0, a lazy dask-backed xarray.DataArray
coarse = dataset.level_data(2) # a coarser pyramid level
levels = dataset.multi_scale_data()
window = dataset.lens(z=(0, 5)) # an ArrayLens: an immutable selection over the dataset
window.data
whole = dataset.lens() # the dataset's whole lens: read, never made
A lens is one row per container and selection, so the same selection asked for twice is the same
lens, and its slices read back the way the server normalized them. Lens itself is the interface
over six kinds. An ArrayLens selects pixels by index slices; tables, sparse datasets, meshes,
networks and annotation collections are selected by value windows instead
(table.lens(t=(0, 10)), expression.lens(gene=4711), collection.lens() for the whole of one), and
a layer names a lens and nothing narrower: mikro.create_point_layer(scene=scene.id, lens=table.lens().id).
That holds for a channel too. An intensity, label or phasor layer draws a lens pinning one channel
(dataset.lens(c=0)), an RGB layer names three of them, and a SPARSE colouring names the sparse lens
that is its slice. Which axis of a lens faces the screen is the layer's to say: layer.render_axes.
A chart: data along one axis
A scene is a place; a chart is one metric axis with values read off it. It adopts a space with exactly one unit-carrying axis, and a layer is drawn where the edge into that space lays it:
from mikro.api.schema import AxisType, PhysicalAxisInput
chart = mikro.create_chart(name="ΔF/F", axis=PhysicalAxisInput(name="t", type=AxisType.TIME, unit=Unit("second")))
chart.world.register(traces, scale={"t": 0.05}) # a (cell, t) array, 50 ms per sample
layer = mikro.create_trace_chart_layer(chart=chart.id, lens=traces.lens().id)
layer.along_axis, layer.series_axis # ("t", "cell"): one line per cell
create_series_chart_layer draws a table's value column, create_annotation_chart_layer makes a
surface to draw marks on, and space.chart() bootstraps a chart from what is already registered.
examples/ holds ten self-contained scripts. Each one simulates an imaging
modality (SMLM, calcium imaging, high-content screening, CLEM, MRI, tractography, ...) and composes
it into a mikro scene, and together they use every layer kind the API offers.
Standalone
Outside arkitekt, you build the client yourself from a MikroRath and a DataLayer, and you use it
as a context manager:
from mikro import Mikro
from mikro.datalayer import DataLayer
from mikro.rath import MikroRath
mikro = Mikro(rath=MikroRath(link=...), datalayer=DataLayer(...))
with mikro:
folder = mikro.create_folder(name="examples")
tests/stack.py shows the complete wiring against a local deployment.
Prerequisites
mikro needs a running mikro-server to connect to. The easiest option is an
Arkitekt deployment. For a local test server,
tests/integration/docker-compose.yml starts mikro together with a database and S3-compatible
object storage.
Development
The generated API (mikro/api/schema.py) is produced by turms
from the schema and the documents in graphql/ (see graphql.config.yaml).
uv run pytest -m "not integration" # no server needed
uv run pytest -m integration # a real mikro deployment via dokker
See RELEASING.md for how versions are cut.
License
MIT, see LICENSE.
1 maintainer
Metadata
1 maintainer
Release files for mikro 8.0.1
For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.
Source distribution (sdist)
| File | Size | Uploaded | |
|---|---|---|---|
| mikro-8.0.1.tar.gz | 431.9 kB | Details |
Built distribution (wheel)
| File | Interpreter | ABI | Platform | Reset |
|---|---|---|---|---|
| mikro-8.0.1-py3-none-any.whl | Python 3 | none | any | Details |
Total release size: 881.7 kB
Release files / mikro-8.0.1.tar.gz
| Download URL | mikro-8.0.1.tar.gz |
|---|---|
| Size | 431.9 kB |
| Tags | Source |
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Release files / mikro-8.0.1-py3-none-any.whl
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| Size | 449.8 kB |
| Tags | Python 3 |
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