Finn Völkel / Nov 04 2020
Remix of Python by Nextjournal
Visualization of MRI volume slices
This notebook demonstrates an interactive pyplot animation, more precisely an animation with a slider that cycles through MRI cross-sections of a human brain.
Example taken from https://plotly.com/python/visualizing-mri-volume-slices/.
# Import data
import time
import numpy as np
from skimage import io
vol = io.imread("https://s3.amazonaws.com/assets.datacamp.com/blog_assets/attention-mri.tif")
volume = vol.T
r, c = volume[0].shape
# Define frames
import plotly.graph_objects as go
nb_frames = 68
fig = go.Figure(frames=[go.Frame(data=go.Surface(
z=(6.7 - k * 0.1) * np.ones((r, c)),
surfacecolor=np.flipud(volume[67 - k]),
cmin=0, cmax=200
),
name=str(k) # you need to name the frame for the animation to behave properly
)
for k in range(nb_frames)])
# Add data to be displayed before animation starts
fig.add_trace(go.Surface(
z=6.7 * np.ones((r, c)),
surfacecolor=np.flipud(volume[67]),
colorscale='Gray',
cmin=0, cmax=200,
colorbar=dict(thickness=20, ticklen=4)
))
def frame_args(duration):
return {
"frame": {"duration": duration},
"mode": "immediate",
"fromcurrent": True,
"transition": {"duration": duration, "easing": "linear"},
}
sliders = [
{
"pad": {"b": 10, "t": 60},
"len": 0.9,
"x": 0.1,
"y": 0,
"steps": [
{
"args": [[f.name], frame_args(0)],
"label": str(k),
"method": "animate",
}
for k, f in enumerate(fig.frames)
],
}
]
# Layout
fig.update_layout(
title='Slices in volumetric data',
width=600,
height=600,
scene=dict(
zaxis=dict(range=[-0.1, 6.8], autorange=False),
aspectratio=dict(x=1, y=1, z=1),
),
updatemenus = [
{
"buttons": [
{
"args": [None, frame_args(50)],
"label": "▶", # play symbol
"method": "animate",
},
{
"args": [[None], frame_args(0)],
"label": "◼", # pause symbol
"method": "animate",
},
],
"direction": "left",
"pad": {"r": 10, "t": 70},
"type": "buttons",
"x": 0.1,
"y": 0,
}
],
sliders=sliders
)
fig
42.8s
Python