"""Second-order texture features derived from the gray-level co-occurrence matrix."""
from ._measurement_info import Entry, MeasurementInfo
[docs]
class TEXTURE(MeasurementInfo):
"""Second-order texture features derived from the gray-level co-occurrence matrix (GLCM).
All features assume normalized GLCMs computed at one or more pixel offsets and averaged
across directions unless otherwise noted. Values depend on quantization, window size,
and scale; interpret ranges comparatively within the same imaging setup.
"""
[docs]
@classmethod
def category(cls) -> str:
return "Texture"
ANGULAR_SECOND_MOMENT = Entry(
"AngularSecondMoment",
"""Angular second moment (energy / uniformity). Measures the degree of local homogeneity
(Σ p(i,j)²). High values → uniform texture (e.g., smooth, yeast-like colonies with consistent
mycelial density). Low values → heterogeneous surfaces (e.g., sectored, wrinkled, or mixed
sporulation zones). Reflects colony surface regularity rather than brightness.""",
)
CONTRAST = Entry(
"Contrast",
"""Contrast (local intensity variation; Σ (i–j)² p(i,j)). High values indicate strong gray-level
differences (e.g., sharply defined rings, radial sectors, raised or folded regions). Low values
indicate gradual tonal changes or uniformly pigmented colonies. Quantifies visual roughness
and zonation amplitude.""",
)
CORRELATION = Entry(
"Correlation",
"""Linear gray-level correlation between neighboring pixels. Positive, high values suggest
structured spatial dependence (e.g., oriented radial hyphae or concentric patterns); near-zero
values indicate uncorrelated, disordered growth (e.g., diffuse cottony mycelium). Sensitive to
illumination gradients and directional GLCM computation.""",
)
VARIANCE = Entry(
"HaralickVariance",
"""GLCM variance (Σ (i–μ)² p(i,j)). Captures spread of co-occurring gray-level pairs, distinct
from raw intensity variance. High values → complex, multi-zone textures with variable
hyphal/spore densities. Low values → consistent gray-level relationships and simpler colony
surfaces.""",
)
INVERSE_DIFFERENCE_MOMENT = Entry(
"InverseDifferenceMoment",
"""Homogeneity (Σ p(i,j) / (1 + (i–j)²)). High values → smooth, locally uniform textures
(e.g., glabrous colonies, uniform aerial mycelium). Low values → abrupt gray-level changes
(e.g., granular sporulation, wrinkled surfaces). Typically inversely correlated with Contrast.""",
)
SUM_AVERAGE = Entry(
"SumAverage",
"""Mean of gray-level sums (Σ k·p_{x+y}(k)). Reflects the average intensity combination of
neighboring pixels. In fungal colonies, can loosely parallel mean colony brightness when
illumination and exposure are controlled, but remains a second-order rather than first-order
intensity metric.""",
)
SUM_VARIANCE = Entry(
"SumVariance",
"""Variance of gray-level sum distribution. High values → heterogeneous brightness zones
(e.g., alternating dense/sparse or pigmented/non-pigmented regions). Low values → uniform
tone across the colony. Often correlated with Contrast; use comparatively within one setup.""",
)
SUM_ENTROPY = Entry(
"SumEntropy",
"""Entropy of the gray-level sum distribution. High values → diverse brightness combinations
and irregular zonation. Low values → repetitive or periodic brightness patterns (e.g., evenly
spaced rings). Indicates spatial unpredictability of summed intensities.""",
)
ENTROPY = Entry(
"Entropy",
"""Global GLCM entropy (–Σ p(i,j)·log p(i,j)). Measures total texture disorder and information
content. High values → complex, irregular colony surfaces (powdery, fuzzy, or sectored growth).
Low values → simple, smooth, predictable patterns (glabrous or uniform colonies). Sensitive to
gray-level quantization and image dynamic range.""",
)
DIFFERENCE_VARIANCE = Entry(
"DiffVariance",
"""Variance of gray-level difference distribution. High values → mixture of smooth and textured
regions (e.g., smooth margins with wrinkled centers). Low values → consistent edge content.
Highlights heterogeneity in edge magnitude across the colony.""",
)
DIFFERENCE_ENTROPY = Entry(
"DiffEntropy",
"""Entropy of gray-level difference distribution. High values → irregular, unpredictable
intensity transitions (e.g., random sporulation or uneven mycelial networks). Low values →
regular periodic transitions (e.g., concentric zonation). Reflects randomness of local contrast
rather than its magnitude.""",
)
IMC1 = Entry(
"InfoCorrelation1",
"""Information measure of correlation 1. Compares joint vs marginal entropies to quantify
mutual dependence between gray levels. Positive values → structured, predictable textures
(e.g., organized radial growth); near-zero → independence between adjacent regions.
Direction of sign varies with implementation.""",
)
IMC2 = Entry(
"InfoCorrelation2",
"""Information measure of correlation 2 (√[1 – exp(–2 (H_xy2–H_xy))]). Always ≥ 0.
Values approaching 1 → strong spatial dependence and organized architecture (e.g., symmetric
rings, radial structure). Values near 0 → random, independent patterns. Captures nonlinear
organization missed by linear correlation.""",
)
