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- # Ultralytics YOLO 🚀, AGPL-3.0 license
- import torch
- from ultralytics.engine.results import Results
- from ultralytics.models.fastsam.utils import bbox_iou
- from ultralytics.models.yolo.detect.predict import DetectionPredictor
- from ultralytics.utils import DEFAULT_CFG, ops
- class FastSAMPredictor(DetectionPredictor):
- """
- FastSAMPredictor is specialized for fast SAM (Segment Anything Model) segmentation prediction tasks in Ultralytics
- YOLO framework.
- This class extends the DetectionPredictor, customizing the prediction pipeline specifically for fast SAM.
- It adjusts post-processing steps to incorporate mask prediction and non-max suppression while optimizing
- for single-class segmentation.
- Attributes:
- cfg (dict): Configuration parameters for prediction.
- overrides (dict, optional): Optional parameter overrides for custom behavior.
- _callbacks (dict, optional): Optional list of callback functions to be invoked during prediction.
- """
- def __init__(self, cfg=DEFAULT_CFG, overrides=None, _callbacks=None):
- """
- Initializes the FastSAMPredictor class, inheriting from DetectionPredictor and setting the task to 'segment'.
- Args:
- cfg (dict): Configuration parameters for prediction.
- overrides (dict, optional): Optional parameter overrides for custom behavior.
- _callbacks (dict, optional): Optional list of callback functions to be invoked during prediction.
- """
- super().__init__(cfg, overrides, _callbacks)
- self.args.task = "segment"
- def postprocess(self, preds, img, orig_imgs):
- """
- Perform post-processing steps on predictions, including non-max suppression and scaling boxes to original image
- size, and returns the final results.
- Args:
- preds (list): The raw output predictions from the model.
- img (torch.Tensor): The processed image tensor.
- orig_imgs (list | torch.Tensor): The original image or list of images.
- Returns:
- (list): A list of Results objects, each containing processed boxes, masks, and other metadata.
- """
- p = ops.non_max_suppression(
- preds[0],
- self.args.conf,
- self.args.iou,
- agnostic=self.args.agnostic_nms,
- max_det=self.args.max_det,
- nc=1, # set to 1 class since SAM has no class predictions
- classes=self.args.classes,
- )
- full_box = torch.zeros(p[0].shape[1], device=p[0].device)
- full_box[2], full_box[3], full_box[4], full_box[6:] = img.shape[3], img.shape[2], 1.0, 1.0
- full_box = full_box.view(1, -1)
- critical_iou_index = bbox_iou(full_box[0][:4], p[0][:, :4], iou_thres=0.9, image_shape=img.shape[2:])
- if critical_iou_index.numel() != 0:
- full_box[0][4] = p[0][critical_iou_index][:, 4]
- full_box[0][6:] = p[0][critical_iou_index][:, 6:]
- p[0][critical_iou_index] = full_box
- if not isinstance(orig_imgs, list): # input images are a torch.Tensor, not a list
- orig_imgs = ops.convert_torch2numpy_batch(orig_imgs)
- results = []
- proto = preds[1][-1] if len(preds[1]) == 3 else preds[1] # second output is len 3 if pt, but only 1 if exported
- for i, pred in enumerate(p):
- orig_img = orig_imgs[i]
- img_path = self.batch[0][i]
- if not len(pred): # save empty boxes
- masks = None
- elif self.args.retina_masks:
- pred[:, :4] = ops.scale_boxes(img.shape[2:], pred[:, :4], orig_img.shape)
- masks = ops.process_mask_native(proto[i], pred[:, 6:], pred[:, :4], orig_img.shape[:2]) # HWC
- else:
- masks = ops.process_mask(proto[i], pred[:, 6:], pred[:, :4], img.shape[2:], upsample=True) # HWC
- pred[:, :4] = ops.scale_boxes(img.shape[2:], pred[:, :4], orig_img.shape)
- results.append(Results(orig_img, path=img_path, names=self.model.names, boxes=pred[:, :6], masks=masks))
- return results
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