trackingBench / src /cell_tracking /evaluation /wormtrack_verify.py
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Document WormTrack-Verify alpha scope and pinned source inventory (#1)
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"""Explicit pilot diagnostics for association-only corruption and abstention.
These metrics are defined in the benchmark specification, not replacements for
canonical HOTA/IDF1. Detections stay fixed. One global identity alignment is allowed.
"""
from __future__ import annotations
import itertools
import numpy as np
import pandas as pd
from scipy.optimize import linear_sum_assignment
from sklearn.metrics import average_precision_score, roc_auc_score
from cell_tracking.data.wormtrack_verify.adapters import TRUSTED, XYZ, validate_tracks
def corrupt_tracks(tracks, *, kind, seed, start_frame, stop_frame=None, pair=None):
"""Deterministic swaps/fragmentation with row-level error labels and fixed observations.
Labels mark correspondence to the original reference identity. Purely global
renaming is not an error; start_frame must follow the first reference frame.
Original images, detection IDs, and coordinates are preserved.
"""
validate_tracks(tracks)
if not set(tracks.annotation_type).issubset(TRUSTED):
raise ValueError("Corruptions require independently trusted source annotations")
if tracks.recording_id.nunique() != 1 or tracks.label_set.nunique() != 1:
raise ValueError("Corrupt one recording and one label set at a time")
frames = sorted(tracks.frame_index.unique())
if start_frame <= frames[0] or start_frame > frames[-1]:
raise ValueError("Corruption must follow the identity anchor and lie inside the recording")
stop_frame = frames[-1] + 1 if stop_frame is None else stop_frame
if stop_frame <= start_frame or stop_frame > frames[-1] + 1:
raise ValueError("Invalid corruption interval")
rng = np.random.default_rng(seed)
ids = sorted(tracks.track_id.unique())
if pair is None:
if len(ids) < 2:
raise ValueError("Need two tracks")
pair = list(rng.choice(ids, 2, replace=False))
if len(pair) != 2 or pair[0] == pair[1] or not set(pair).issubset(ids):
raise ValueError("Pair must identify two distinct source tracks")
df = tracks.copy()
df["reference_track_id"] = df.track_id
interval = (df.frame_index >= start_frame) & (df.frame_index < stop_frame)
affected = interval & df.track_id.isin(pair)
if not affected.any():
raise ValueError("No observations in the selected corruption interval")
if kind in {"single_frame_swap", "persistent_swap", "swap_recovery", "nearby_swap"}:
if kind == "single_frame_swap":
affected &= df.frame_index == start_frame
df.loc[affected, "track_id"] = df.loc[affected, "track_id"].map(
{pair[0]: pair[1], pair[1]: pair[0]}
)
elif kind == "fragmentation":
affected = interval & (df.track_id == pair[0])
df.loc[affected, "track_id"] = pair[0] + f":fragment:{seed}"
elif kind == "dropout":
affected = interval & (df.track_id == pair[0])
df.loc[affected, "validity"] = False
else:
raise ValueError(f"Unsupported pilot corruption: {kind}")
df["is_error"] = affected
df["corruption_type"] = kind
df["seed"] = seed
df["scenario_id"] = f"{kind}:seed{seed}"
return df
def association_metrics(reference, prediction):
"""Score shared oracle detections with one recording-wide identity permutation.
Missing predictions count against coverage and correct-observation rate.
Switches are changes in predicted identity along each reference trajectory;
fragmented runs also count reappearance after a missing prediction. Evaluation
covers only source-supported reference observations, not unannotated frames.
"""
validate_tracks(reference)
validate_tracks(prediction)
if reference.recording_id.nunique() != 1 or prediction.recording_id.nunique() != 1:
raise ValueError("Evaluate each independent recording separately")
if reference.recording_id.iloc[0] != prediction.recording_id.iloc[0]:
raise ValueError("Mismatched recording")
key = ["frame_index", "detection_id"]
valid_prediction = prediction.loc[prediction.validity]
joined = reference.loc[reference.validity].merge(
valid_prediction[key + ["track_id"]],
on=key,
how="left",
suffixes=("_gt", "_pred"),
validate="one_to_one",
)
gt = sorted(joined.track_id_gt.unique())
pred = sorted(valid_prediction.track_id.unique())
counts = (
pd.crosstab(joined.track_id_gt, joined.track_id_pred)
.reindex(index=gt, columns=pred, fill_value=0)
.to_numpy()
)
mapping = {}
if counts.size:
rows, cols = linear_sum_assignment(-counts)
mapping = {pred[c]: gt[r] for r, c in zip(rows, cols, strict=True)}
correct = joined.track_id_pred.map(mapping).eq(joined.track_id_gt)
switches = fragments = 0
for _, group in joined.sort_values("frame_index").groupby("track_id_gt"):
ids = group.track_id_pred.tolist()
observed = [i for i in ids if pd.notna(i)]
switches += sum(a != b for a, b in itertools.pairwise(observed))
fragments += max(
0,
sum(
pd.notna(v) and (j == 0 or pd.isna(ids[j - 1]) or v != ids[j - 1])
for j, v in enumerate(ids)
)
- 1,
)
extra = len(
valid_prediction.merge(joined[key], on=key, how="left", indicator=True).query(
'_merge == "left_only"'
)
)
return {
"reference_observations": len(joined),
"predicted_observations": len(valid_prediction),
"coverage": float(joined.track_id_pred.notna().mean()),
"correct_observation_rate": float(correct.mean()),
"identity_switches": int(switches),
"fragmentations": int(fragments),
"extra_observations": int(extra),
}
def reference_residual_scores(tracks, reference_cloud, *, physical=True):
"""Identity-sensitive distance from the fixed first-frame reference.
This intentionally simple consistency diagnostic includes genuine tissue motion.
It is not an independent deformation model or a certificate of correctness.
Reference cloud must come from an independently trusted reference observation.
"""
cols = [f"{a}_um" for a in "xyz"] if physical else XYZ
ref = reference_cloud.set_index("track_id")
if ref.index.duplicated().any():
raise ValueError("Reference identities must be unique")
a = tracks[cols].to_numpy(dtype=float)
b = ref.reindex(tracks.track_id)[cols].to_numpy(dtype=float)
scores = np.linalg.norm(a - b, axis=1)
scores[~tracks.validity.to_numpy()] = np.inf
# Unseen fragment IDs are unsupported; preserve absence rather than fit a new anatomy.
scores[np.isnan(scores)] = np.inf
return scores
def verifier_metrics(scores, is_error, *, threshold):
"""Fixed-population selective risk/coverage; ties enter a risk curve together.
False certification = accepted errors / all labeled errors. Selective risk =
accepted errors / accepted observations. Unsupported scores abstain. Threshold
must be specified before evaluation; this function does not select it.
"""
scores = np.asarray(scores, dtype=float)
labels = np.asarray(is_error, dtype=bool)
if len(scores) != len(labels) or not len(scores) or np.isnan(scores).any():
raise ValueError("Scores and labels must be aligned, nonempty, and non-NaN")
if np.isnan(threshold):
raise ValueError("Threshold cannot be NaN")
accept = np.isfinite(scores) & (scores <= threshold)
# Infinity denotes abstention; map it above all finite scores for ranking metrics.
finite = scores[np.isfinite(scores)]
ranked = np.where(np.isfinite(scores), scores, (finite.max() + 1 if len(finite) else 1))
both = labels.any() and not labels.all()
curve = []
order = np.flatnonzero(np.isfinite(scores))
order = order[np.argsort(scores[order], kind="stable")]
if len(order):
ordered_scores = scores[order]
cumulative_errors = np.cumsum(labels[order])
ends = np.r_[np.flatnonzero(np.diff(ordered_scores) != 0), len(order) - 1]
curve = [
{
"threshold": float(ordered_scores[i]),
"coverage": float((i + 1) / len(scores)),
"risk": float(cumulative_errors[i] / (i + 1)),
}
for i in ends
]
return {
"observations": len(scores),
"error_prevalence": float(labels.mean()),
"auroc": float(roc_auc_score(labels, ranked)) if both else None,
"auprc": float(average_precision_score(labels, ranked)) if both else None,
"false_certification_rate": float((accept & labels).sum() / labels.sum())
if labels.any()
else None,
"certified_coverage": float(accept.mean()),
"selective_risk": float(labels[accept].mean()) if accept.any() else None,
"correct_certified_coverage": float((accept & ~labels).mean()),
"threshold": float(threshold),
"risk_coverage": curve,
}
def oracle_association_baseline(detections, *, method="hungarian", physical=True):
"""Untrained Euclidean nearest-neighbor or bipartite association on fixed detections."""
if method not in {"nearest_neighbor", "hungarian"}:
raise ValueError(method)
cols = [f"{a}_um" for a in "xyz"] if physical else XYZ
output = []
previous = None
next_id = 0
for frame, points in detections.sort_values("frame_index").groupby("frame_index"):
points = points.copy().reset_index(drop=True)
xyz = points[cols].to_numpy(dtype=float)
if not np.isfinite(xyz).all():
raise ValueError("Baseline requires valid coordinates in the selected units")
ids = [None] * len(points)
if previous is not None:
old_xyz, old_ids = previous
distance = np.linalg.norm(old_xyz[:, None] - xyz[None], axis=2)
if method == "hungarian":
rows, columns = linear_sum_assignment(distance)
else:
pairs = sorted((distance[i, j], i, j) for i, j in enumerate(distance.argmin(1)))
chosen = set()
matches = []
for _, i, j in pairs:
if j not in chosen:
matches.append((i, j))
chosen.add(j)
rows = [p[0] for p in matches]
columns = [p[1] for p in matches]
for i, j in zip(rows, columns, strict=True):
ids[j] = old_ids[i]
for i, identity in enumerate(ids):
if identity is None:
ids[i] = f"baseline:{next_id}"
next_id += 1
points["track_id"] = ids
points["annotation_type"] = "algorithm_prediction"
points["label_set"] = "prediction"
output.append(points)
previous = xyz, ids
return pd.concat(output, ignore_index=True)