Test images¶
16 grayscale 2D images for testing and benchmarking orientation analysis: 9 synthetic, whose orientation is known by construction, and 7 real images. Each image comes with a binary mask of its meaningful structures, and with an overview panel of the results.
The folder holds the 16 source images in images/, the 16 binary masks in masks/, and in results/ one overview panel per image (original, mask, orientation, coherency, energy, color survey, masked distribution, vector field). All of it is computed with the OrientationJ Python port at the plugin defaults (cubic-spline gradient, σ = 1). The images are listed below in the order of the montage; click a panel for full size.
cell_aemisegger 
¶
728 × 728, uint8, values in [0, 252] — real: fluorescence cell, actin fibers.
Download: image · mask · orientation · coherency · energy
collagen ¶
512 × 512, uint8, values in [2, 255] — real: collagen fibers.
Download: image · mask · orientation · coherency · energy
dendrochronology ¶
512 × 512, uint8, values in [0, 255] — real: wood section, growth rings.
fibronectin_arafat_plos2025 ¶
1024 × 1024, uint8, values in [0, 255] — real: fibronectin network (Arafat et al., PLOS ONE 2025).
M. Arafat et al., PLOS ONE (2025), doi:10.1371/journal.pone.0320006.
fibrous_tissues_fibero2024 ¶
2048 × 2048, uint16, values in [87, 4094] — real: fibrous tissue (FiberO, 2024).
FiberO dataset (2024), doi:10.3389/fbioe.2024.1497837.
fiji_directionality_montage¶
1536 × 1536, uint16, values in [3089, 65535] — real: montage from the Fiji Directionality documentation.
Montage from the documentation of the Fiji Directionality plugin.
nanofiber_fiji_diameterj ¶
512 × 512, uint8, values in [0, 255] — real: SEM nanofibers (DiameterJ sample).
DiameterJ sample — S. A. Hotaling et al., Data in Brief (2015), doi:10.1016/j.dib.2015.07.012.
polymer_slice_quanfima2018 ¶
600 × 600, float32, values in [−0.0029, 0.0030] — real: polymer slice (quanfima, 2018).
synthetic_chirp_1024¶
1024 × 1024, float32, values in [0, 1] — synthetic: radial chirp with a frequency sweep; the tangential ground-truth orientation is known at every pixel.
Download: image · mask · orientation · coherency · energy
synthetic_filaments_512¶
512 × 512, float32, values in [0, 1] — synthetic: random curved filaments.
synthetic_nematic_512¶
512 × 512, float32, values in [0, 1] — synthetic: nematic-like texture with a dominant direction.
Pattern inspired by active nematics — A. Doostmohammadi, J. Ignés-Mullol, J. M. Yeomans, F. Sagués, Active nematics, Nature Communications 9:3246 (2018), doi:10.1038/s41467-018-05666-8.
synthetic_noise_512¶
512 × 512, float32, values in [0, 1] — synthetic: isotropic noise; any measured anisotropy is bias.
synthetic_rings_dither_512¶
512 × 512, float32, values in [0, 1] — synthetic: thin concentric rings with a small dither (σ = 10⁻⁴) that avoids degenerate-tensor spikes; exact tangential truth.
synthetic_spiral_512¶
512 × 512, float32, values in [0, 1] — synthetic: spiral.
synthetic_wave_512¶
512 × 512, float32, values in [0, 1] — synthetic: three waves with fringes at exactly 5°, 45° and 85° and periods of 2, 8 and 64 px, plus uniform noise, in a circular Tukey window of 480 px.
z_artificial_fibers¶
683 × 512, uint8, values in [0, 225] — artificial: fiber phantom (drawn, not generated by the synthetic-image notebook).
