> For the complete documentation index, see [llms.txt](https://docs.roboflow.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.roboflow.com/workflows/developer-guide/developer-guide/kinds/detections-overlaps.md).

# detectionsoverlaps Kind

List of per-pair detection overlap records

## Data representation

### External

External data representation is relevant for Workflows clients - it dictates what is the input and output format of data.

Type: `List[Dict[str, Any]]`

### Internal

Internal data representation is relevant for Workflows blocks creators - this is the type that will be provided by Execution Engine in runtime to the block that consumes input of this kind.

Type: `List[Dict[str, Any]]`

## Details

List of per-pair overlap records computed between two sets of detections at the same dimensionality. Internally and on the wire: `List[Dict[str, Any]]`.

Each record is a dict with the following keys.

**Always present:**

* `reference_class: Optional[str]` - `class_name` of the reference-side detection. `None` when the source `sv.Detections` does not carry `class_name`.
* `reference_confidence: Optional[float]` - Confidence of the reference-side detection. `None` when the source `sv.Detections.confidence` is `None`.
* `candidate_class: Optional[str]` - `class_name` of the candidate-side detection (same nullability rules).
* `candidate_confidence: Optional[float]` - Confidence of the candidate-side detection (same nullability rules).
* `overlap_ratio: float` - `intersection_area(reference_polygon, candidate_polygon) / reference_polygon.area`. Range `[0.0, 1.0]`. The denominator is *always* the reference detection's area, so the relation is not symmetric across the two inputs. Polygons come from masks when available (longest contour, validated), otherwise from the bounding-box rectangle.

**Conditionally present** (only when the source `sv.Detections.data` carries `detection_id` for that side):

* `reference_detection_id: Optional[str]`
* `candidate_detection_id: Optional[str]`

Records below the configured `min_overlap` threshold are not emitted. The top-level list is unordered with respect to pair identity; do not rely on positional indexing to cross-reference back into the input batches - use `reference_detection_id` / `candidate_detection_id` instead.