Reference for ultralytics/utils/loss.py
Note
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ultralytics.utils.loss.VarifocalLoss
Bases: Module
Varifocal loss by Zhang et al.
https://arxiv.org/abs/2008.13367.
Source code in ultralytics/utils/loss.py
forward
staticmethod
Computes varfocal loss.
Source code in ultralytics/utils/loss.py
ultralytics.utils.loss.FocalLoss
Bases: Module
Wraps focal loss around existing loss_fcn(), i.e. criteria = FocalLoss(nn.BCEWithLogitsLoss(), gamma=1.5).
Source code in ultralytics/utils/loss.py
forward
staticmethod
Calculates and updates confusion matrix for object detection/classification tasks.
Source code in ultralytics/utils/loss.py
ultralytics.utils.loss.DFLoss
Bases: Module
Criterion class for computing DFL losses during training.
Source code in ultralytics/utils/loss.py
__call__
Return sum of left and right DFL losses.
Distribution Focal Loss (DFL) proposed in Generalized Focal Loss https://ieeexplore.ieee.org/document/9792391
Source code in ultralytics/utils/loss.py
ultralytics.utils.loss.BboxLoss
Bases: Module
Criterion class for computing training losses during training.
Source code in ultralytics/utils/loss.py
forward
forward(
pred_dist,
pred_bboxes,
anchor_points,
target_bboxes,
target_scores,
target_scores_sum,
fg_mask,
)
IoU loss.
Source code in ultralytics/utils/loss.py
ultralytics.utils.loss.RotatedBboxLoss
Bases: BboxLoss
Criterion class for computing training losses during training.
Source code in ultralytics/utils/loss.py
forward
forward(
pred_dist,
pred_bboxes,
anchor_points,
target_bboxes,
target_scores,
target_scores_sum,
fg_mask,
)
IoU loss.
Source code in ultralytics/utils/loss.py
ultralytics.utils.loss.KeypointLoss
Bases: Module
Criterion class for computing training losses.
Source code in ultralytics/utils/loss.py
forward
Calculates keypoint loss factor and Euclidean distance loss for predicted and actual keypoints.
Source code in ultralytics/utils/loss.py
ultralytics.utils.loss.v8DetectionLoss
Criterion class for computing training losses.
Source code in ultralytics/utils/loss.py
__call__
Calculate the sum of the loss for box, cls and dfl multiplied by batch size.
Source code in ultralytics/utils/loss.py
bbox_decode
Decode predicted object bounding box coordinates from anchor points and distribution.
Source code in ultralytics/utils/loss.py
preprocess
Preprocesses the target counts and matches with the input batch size to output a tensor.
Source code in ultralytics/utils/loss.py
ultralytics.utils.loss.v8SegmentationLoss
Bases: v8DetectionLoss
Criterion class for computing training losses.
Source code in ultralytics/utils/loss.py
__call__
Calculate and return the loss for the YOLO model.
Source code in ultralytics/utils/loss.py
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|
calculate_segmentation_loss
calculate_segmentation_loss(
fg_mask: torch.Tensor,
masks: torch.Tensor,
target_gt_idx: torch.Tensor,
target_bboxes: torch.Tensor,
batch_idx: torch.Tensor,
proto: torch.Tensor,
pred_masks: torch.Tensor,
imgsz: torch.Tensor,
overlap: bool,
) -> torch.Tensor
Calculate the loss for instance segmentation.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
fg_mask
|
Tensor
|
A binary tensor of shape (BS, N_anchors) indicating which anchors are positive. |
required |
masks
|
Tensor
|
Ground truth masks of shape (BS, H, W) if |
required |
target_gt_idx
|
Tensor
|
Indexes of ground truth objects for each anchor of shape (BS, N_anchors). |
required |
target_bboxes
|
Tensor
|
Ground truth bounding boxes for each anchor of shape (BS, N_anchors, 4). |
required |
batch_idx
|
Tensor
|
Batch indices of shape (N_labels_in_batch, 1). |
required |
proto
|
Tensor
|
Prototype masks of shape (BS, 32, H, W). |
required |
pred_masks
|
Tensor
|
Predicted masks for each anchor of shape (BS, N_anchors, 32). |
required |
imgsz
|
Tensor
|
Size of the input image as a tensor of shape (2), i.e., (H, W). |
required |
overlap
|
bool
|
Whether the masks in |
required |
Returns:
Type | Description |
---|---|
Tensor
|
The calculated loss for instance segmentation. |
Notes
The batch loss can be computed for improved speed at higher memory usage. For example, pred_mask can be computed as follows: pred_mask = torch.einsum('in,nhw->ihw', pred, proto) # (i, 32) @ (32, 160, 160) -> (i, 160, 160)
Source code in ultralytics/utils/loss.py
single_mask_loss
staticmethod
single_mask_loss(
gt_mask: torch.Tensor,
pred: torch.Tensor,
proto: torch.Tensor,
xyxy: torch.Tensor,
area: torch.Tensor,
) -> torch.Tensor
Compute the instance segmentation loss for a single image.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
gt_mask
|
Tensor
|
Ground truth mask of shape (n, H, W), where n is the number of objects. |
required |
pred
|
Tensor
|
Predicted mask coefficients of shape (n, 32). |
required |
proto
|
Tensor
|
Prototype masks of shape (32, H, W). |
required |
xyxy
|
Tensor
|
Ground truth bounding boxes in xyxy format, normalized to [0, 1], of shape (n, 4). |
required |
area
|
Tensor
|
Area of each ground truth bounding box of shape (n,). |
required |
Returns:
Type | Description |
---|---|
Tensor
|
The calculated mask loss for a single image. |
Notes
The function uses the equation pred_mask = torch.einsum('in,nhw->ihw', pred, proto) to produce the predicted masks from the prototype masks and predicted mask coefficients.
Source code in ultralytics/utils/loss.py
ultralytics.utils.loss.v8PoseLoss
Bases: v8DetectionLoss
Criterion class for computing training losses.
Source code in ultralytics/utils/loss.py
__call__
Calculate the total loss and detach it.
Source code in ultralytics/utils/loss.py
calculate_keypoints_loss
calculate_keypoints_loss(
masks,
target_gt_idx,
keypoints,
batch_idx,
stride_tensor,
target_bboxes,
pred_kpts,
)
Calculate the keypoints loss for the model.
This function calculates the keypoints loss and keypoints object loss for a given batch. The keypoints loss is based on the difference between the predicted keypoints and ground truth keypoints. The keypoints object loss is a binary classification loss that classifies whether a keypoint is present or not.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
masks
|
Tensor
|
Binary mask tensor indicating object presence, shape (BS, N_anchors). |
required |
target_gt_idx
|
Tensor
|
Index tensor mapping anchors to ground truth objects, shape (BS, N_anchors). |
required |
keypoints
|
Tensor
|
Ground truth keypoints, shape (N_kpts_in_batch, N_kpts_per_object, kpts_dim). |
required |
batch_idx
|
Tensor
|
Batch index tensor for keypoints, shape (N_kpts_in_batch, 1). |
required |
stride_tensor
|
Tensor
|
Stride tensor for anchors, shape (N_anchors, 1). |
required |
target_bboxes
|
Tensor
|
Ground truth boxes in (x1, y1, x2, y2) format, shape (BS, N_anchors, 4). |
required |
pred_kpts
|
Tensor
|
Predicted keypoints, shape (BS, N_anchors, N_kpts_per_object, kpts_dim). |
required |
Returns:
Name | Type | Description |
---|---|---|
kpts_loss |
Tensor
|
The keypoints loss. |
kpts_obj_loss |
Tensor
|
The keypoints object loss. |
Source code in ultralytics/utils/loss.py
kpts_decode
staticmethod
Decodes predicted keypoints to image coordinates.
Source code in ultralytics/utils/loss.py
ultralytics.utils.loss.v8ClassificationLoss
Criterion class for computing training losses.
__call__
Compute the classification loss between predictions and true labels.
ultralytics.utils.loss.v8OBBLoss
Bases: v8DetectionLoss
Calculates losses for object detection, classification, and box distribution in rotated YOLO models.
Source code in ultralytics/utils/loss.py
__call__
Calculate and return the loss for the YOLO model.
Source code in ultralytics/utils/loss.py
bbox_decode
Decode predicted object bounding box coordinates from anchor points and distribution.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
anchor_points
|
Tensor
|
Anchor points, (h*w, 2). |
required |
pred_dist
|
Tensor
|
Predicted rotated distance, (bs, h*w, 4). |
required |
pred_angle
|
Tensor
|
Predicted angle, (bs, h*w, 1). |
required |
Returns:
Type | Description |
---|---|
Tensor
|
Predicted rotated bounding boxes with angles, (bs, h*w, 5). |
Source code in ultralytics/utils/loss.py
preprocess
Preprocesses the target counts and matches with the input batch size to output a tensor.
Source code in ultralytics/utils/loss.py
ultralytics.utils.loss.E2EDetectLoss
Criterion class for computing training losses.
Source code in ultralytics/utils/loss.py
__call__
Calculate the sum of the loss for box, cls and dfl multiplied by batch size.