roboflow/supervision · error · ValueError

Precision with `MetricTarget.MASKS` requires detections to i

Error message

Precision with `MetricTarget.MASKS` requires detections to include masks.

What it means

Error "Precision with `MetricTarget.MASKS` requires detections to include masks." thrown in roboflow/supervision.

Source

Thrown at src/supervision/metrics/precision.py:522

        precision = np.divide(
            true_positives,
            denominator,
            out=np.zeros_like(true_positives),
            where=denominator != 0,
        )

        result_precision: npt.NDArray[np.float64] = precision
        return result_precision

    def _detections_content(self, detections: Detections) -> npt.NDArray[Any]:
        """Return boxes, masks or oriented bounding boxes from detections."""
        if self._metric_target == MetricTarget.BOXES:
            return cast(npt.NDArray[Any], detections.xyxy)
        if self._metric_target == MetricTarget.MASKS:
            if detections.mask is not None:
                return cast(npt.NDArray[Any], detections.mask)
            if len(detections) > 0:
                raise ValueError(
                    "Precision with `MetricTarget.MASKS` requires detections to "
                    "include masks."
                )
            return self._make_empty_content()
        if self._metric_target == MetricTarget.ORIENTED_BOUNDING_BOXES:
            obb = detections.data.get(ORIENTED_BOX_COORDINATES)
            if obb is not None and len(obb) > 0:
                result_obb: npt.NDArray[np.float32] = np.array(obb, dtype=np.float32)
                return result_obb
            return self._make_empty_content()
        raise ValueError(f"Invalid metric target: {self._metric_target}")

    def _make_empty_content(self) -> npt.NDArray[Any]:
        if self._metric_target == MetricTarget.BOXES:
            empty_boxes: npt.NDArray[np.float32] = np.empty((0, 4), dtype=np.float32)
            return empty_boxes

        if self._metric_target == MetricTarget.MASKS:

View on GitHub (pinned to 7f254d9784)

Solutions

1. Include masks in the Detections when using MetricTarget.MASKS with Precision.
2. If masks are unavailable, use MetricTarget.BOXES instead.

When it happens

Trigger: Thrown at src/supervision/metrics/precision.py:522 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of roboflow/supervision@7f254d9784 (2026-08-15). Data as JSON: /api/errors/46f82535180fa9b8. Report an issue: GitHub.