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functions

GCC-specific thickness calculation functions.

The shared retinal-layer primitives (parse_center_coordinates, build_thickness_map, layer selection, etc.) live in bitfount.steps.data_utils.thickness_metrics and are used by both the CST and GCC steps. The shared per-file orchestration loop lives in bitfount.steps.data_utils.thickness_calculation.

This module provides the GCC-specific glaucoma staging + region statistics (GlaucomaStage, compute_gcc) and the high-level per-file compute_gcc_metrics_for_scan — ported from _GCCWorkerSide in federated/algorithms/ophthalmology/gcc_calculation_algorithm.py (GlaucomaStage lines 39-54, _compute_gcc lines 184-309 and _calculate_metric lines 107-182).

Module​

Functions​

compute_gcc​

def compute_gcc(    thickness_um: NDArray[Any],    center_coords: tuple[float, float, float],    slice_thickness_mm: float,    pixel_spacing_x_mm: float,    radius_mm: float = 1.0,    metric_name: str = 'GCC',) ‑> GCCMetrics | str:

Compute GCC asymmetry index and related metrics.

Ports _GCCWorkerSide._compute_gcc.

Arguments

  • thickness_um: Thickness map in micrometers, shape (num_slices, width).
  • center_coords: Center coordinates (slice, x, y). Only slice and x are used.
  • slice_thickness_mm: Slice thickness in mm.
  • pixel_spacing_x_mm: Pixel spacing in x direction in mm.
  • radius_mm: Radius of circular region in mm.
  • metric_name: Name of the metric being calculated (log text only).

Returns A GCCMetrics object with the computed values, or a calculation_error:<detail> reason string when the region yields no computable thickness — never a partial object.

compute_gcc_metrics_for_scan​

def compute_gcc_metrics_for_scan(    layer_pred: pd.Series,    file_row: pd.Series,    *,    inner_layer: RetinalLayer,    outer_layer: RetinalLayer,    strict_measurement: bool,    landmark_idx: int,    radius_mm: float,    center_landmark_type: str = 'macula',    metric_name: str = 'GCC',) ‑> GCCMetrics | str:

Calculate GCC for a single file.

Ports _GCCWorkerSide._calculate_metric. Per-instance configuration that the legacy worker read from self is passed as explicit parameters.

Arguments

  • layer_pred: Layer segmentation predictions for one file.
  • file_row: Row containing DICOM metadata and macula predictions.
  • inner_layer: Desired inner layer for the thickness measurement.
  • outer_layer: Desired outer layer for the thickness measurement.
  • strict_measurement: If True, only calculate if both desired inner and outer layers are available (no fallback).
  • landmark_idx: Index of the landmark to use (0=start, 1=end, 2=middle).
  • radius_mm: Radius of the circular region in mm.
  • center_landmark_type: Nature of the center landmark ("fovea"/"macula").
  • metric_name: Name of the metric being calculated (log text only).

Returns A GCCMetrics object for a computable file, or a reason string when the file cannot be computed — missing_data:<fields> for absent inputs, calculation_error:<detail> for compute failures. Never a partial object: an incomplete result would give false confidence that a real measurement was produced.

Classes​

GlaucomaStage​

class GlaucomaStage(*args, **kwds):

Enum to indicate stage of Glaucoma.

Ancestors​

Variables​

  • static GREEN
  • static ORANGE
  • static RED
  • static UNKNOWN
  • static YELLOW

Methods​

next_level​

def next_level(self) ‑> GlaucomaStage:

Get one stage worse than current stage.