# tf.raw_ops.CombinedNonMaxSuppression

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Greedily selects a subset of bounding boxes in descending order of score,

#### View aliases


**Compat aliases for migration**

See
[Migration guide](https://www.tensorflow.org/guide/migrate) for
more details.

[`tf.compat.v1.raw_ops.CombinedNonMaxSuppression`](https://www.tensorflow.org/api_docs/python/tf/raw_ops/CombinedNonMaxSuppression)

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    tf.raw_ops.CombinedNonMaxSuppression(
        boxes,
        scores,
        max_output_size_per_class,
        max_total_size,
        iou_threshold,
        score_threshold,
        pad_per_class=False,
        clip_boxes=True,
        name=None
    )

This operation performs non_max_suppression on the inputs per batch, across
all classes.
Prunes away boxes that have high intersection-over-union (IOU) overlap
with previously selected boxes. Bounding boxes are supplied as
\[y1, x1, y2, x2\], where (y1, x1) and (y2, x2) are the coordinates of any
diagonal pair of box corners and the coordinates can be provided as normalized
(i.e., lying in the interval \[0, 1\]) or absolute. Note that this algorithm
is agnostic to where the origin is in the coordinate system. Also note that
this algorithm is invariant to orthogonal transformations and translations
of the coordinate system; thus translating or reflections of the coordinate
system result in the same boxes being selected by the algorithm.
The output of this operation is the final boxes, scores and classes tensor
returned after performing non_max_suppression.

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| ## Args ||
|---|---|
| `boxes` | A `Tensor` of type `float32`. A 4-D float tensor of shape `[batch_size, num_boxes, q, 4]`. If `q` is 1 then same boxes are used for all classes otherwise, if `q` is equal to number of classes, class-specific boxes are used. |
| `scores` | A `Tensor` of type `float32`. A 3-D float tensor of shape `[batch_size, num_boxes, num_classes]` representing a single score corresponding to each box (each row of boxes). |
| `max_output_size_per_class` | A `Tensor` of type `int32`. A scalar integer tensor representing the maximum number of boxes to be selected by non max suppression per class |
| `max_total_size` | A `Tensor` of type `int32`. An int32 scalar representing the maximum number of boxes retained over all classes. Note that setting this value to a large number may result in OOM error depending on the system workload. |
| `iou_threshold` | A `Tensor` of type `float32`. A 0-D float tensor representing the threshold for deciding whether boxes overlap too much with respect to IOU. |
| `score_threshold` | A `Tensor` of type `float32`. A 0-D float tensor representing the threshold for deciding when to remove boxes based on score. |
| `pad_per_class` | An optional `bool`. Defaults to `False`. If false, the output nmsed boxes, scores and classes are padded/clipped to `max_total_size`. If true, the output nmsed boxes, scores and classes are padded to be of length `max_size_per_class`\*`num_classes`, unless it exceeds `max_total_size` in which case it is clipped to `max_total_size`. Defaults to false. |
| `clip_boxes` | An optional `bool`. Defaults to `True`. If true, assume the box coordinates are between \[0, 1\] and clip the output boxes if they fall beyond \[0, 1\]. If false, do not do clipping and output the box coordinates as it is. |
| `name` | A name for the operation (optional). |

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| ## Returns ||
|---|---|
| A tuple of `Tensor` objects (nmsed_boxes, nmsed_scores, nmsed_classes, valid_detections). ||
| `nmsed_boxes` | A `Tensor` of type `float32`. |
| `nmsed_scores` | A `Tensor` of type `float32`. |
| `nmsed_classes` | A `Tensor` of type `float32`. |
| `valid_detections` | A `Tensor` of type `int32`. |

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