Arulkumar03/Fox_Sheep_Detector_Computer_Vision_model

1# Copyright (c) Facebook, Inc. and its affiliates.2import itertools3import logging4from typing import Dict, List5import torch6 7from detectron2.config import configurable8from detectron2.layers import ShapeSpec, batched_nms_rotated, cat9from detectron2.structures import Instances, RotatedBoxes, pairwise_iou_rotated10from detectron2.utils.memory import retry_if_cuda_oom11 12from ..box_regression import Box2BoxTransformRotated13from .build import PROPOSAL_GENERATOR_REGISTRY14from .proposal_utils import _is_tracing15from .rpn import RPN16 17logger = logging.getLogger(__name__)18 19 20def find_top_rrpn_proposals(21    proposals,22    pred_objectness_logits,23    image_sizes,24    nms_thresh,25    pre_nms_topk,26    post_nms_topk,27    min_box_size,28    training,29):30    """31    For each feature map, select the `pre_nms_topk` highest scoring proposals,32    apply NMS, clip proposals, and remove small boxes. Return the `post_nms_topk`33    highest scoring proposals among all the feature maps if `training` is True,34    otherwise, returns the highest `post_nms_topk` scoring proposals for each35    feature map.36 37    Args:38        proposals (list[Tensor]): A list of L tensors. Tensor i has shape (N, Hi*Wi*A, 5).39            All proposal predictions on the feature maps.40        pred_objectness_logits (list[Tensor]): A list of L tensors. Tensor i has shape (N, Hi*Wi*A).41        image_sizes (list[tuple]): sizes (h, w) for each image42        nms_thresh (float): IoU threshold to use for NMS43        pre_nms_topk (int): number of top k scoring proposals to keep before applying NMS.44            When RRPN is run on multiple feature maps (as in FPN) this number is per45            feature map.46        post_nms_topk (int): number of top k scoring proposals to keep after applying NMS.47            When RRPN is run on multiple feature maps (as in FPN) this number is total,48            over all feature maps.49        min_box_size(float): minimum proposal box side length in pixels (absolute units wrt50            input images).51        training (bool): True if proposals are to be used in training, otherwise False.52            This arg exists only to support a legacy bug; look for the "NB: Legacy bug ..."53            comment.54 55    Returns:56        proposals (list[Instances]): list of N Instances. The i-th Instances57            stores post_nms_topk object proposals for image i.58    """59    num_images = len(image_sizes)60    device = proposals[0].device61 62    # 1. Select top-k anchor for every level and every image63    topk_scores = []  # #lvl Tensor, each of shape N x topk64    topk_proposals = []65    level_ids = []  # #lvl Tensor, each of shape (topk,)66    batch_idx = torch.arange(num_images, device=device)67    for level_id, proposals_i, logits_i in zip(68        itertools.count(), proposals, pred_objectness_logits69    ):70        Hi_Wi_A = logits_i.shape[1]71        if isinstance(Hi_Wi_A, torch.Tensor):  # it's a tensor in tracing72            num_proposals_i = torch.clamp(Hi_Wi_A, max=pre_nms_topk)73        else:74            num_proposals_i = min(Hi_Wi_A, pre_nms_topk)75 76        topk_scores_i, topk_idx = logits_i.topk(num_proposals_i, dim=1)77 78        # each is N x topk79        topk_proposals_i = proposals_i[batch_idx[:, None], topk_idx]  # N x topk x 580 81        topk_proposals.append(topk_proposals_i)82        topk_scores.append(topk_scores_i)83        level_ids.append(torch.full((num_proposals_i,), level_id, dtype=torch.int64, device=device))84 85    # 2. Concat all levels together86    topk_scores = cat(topk_scores, dim=1)87    topk_proposals = cat(topk_proposals, dim=1)88    level_ids = cat(level_ids, dim=0)89 90    # 3. For each image, run a per-level NMS, and choose topk results.91    results = []92    for n, image_size in enumerate(image_sizes):93        boxes = RotatedBoxes(topk_proposals[n])94        scores_per_img = topk_scores[n]95        lvl = level_ids96 97        valid_mask = torch.isfinite(boxes.tensor).all(dim=1) & torch.isfinite(scores_per_img)98        if not valid_mask.all():99            if training:100                raise FloatingPointError(101                    "Predicted boxes or scores contain Inf/NaN. Training has diverged."102                )103            boxes = boxes[valid_mask]104            scores_per_img = scores_per_img[valid_mask]105            lvl = lvl[valid_mask]106        boxes.clip(image_size)107 108        # filter empty boxes109        keep = boxes.nonempty(threshold=min_box_size)110        if _is_tracing() or keep.sum().item() != len(boxes):111            boxes, scores_per_img, lvl = (boxes[keep], scores_per_img[keep], lvl[keep])112 113        keep = batched_nms_rotated(boxes.tensor, scores_per_img, lvl, nms_thresh)114        # In Detectron1, there was different behavior during training vs. testing.115        # (https://github.com/facebookresearch/Detectron/issues/459)116        # During training, topk is over the proposals from *all* images in the training batch.117        # During testing, it is over the proposals for each image separately.118        # As a result, the training behavior becomes batch-dependent,119        # and the configuration "POST_NMS_TOPK_TRAIN" end up relying on the batch size.120        # This bug is addressed in Detectron2 to make the behavior independent of batch size.121        keep = keep[:post_nms_topk]122 123        res = Instances(image_size)124        res.proposal_boxes = boxes[keep]125        res.objectness_logits = scores_per_img[keep]126        results.append(res)127    return results128 129 130@PROPOSAL_GENERATOR_REGISTRY.register()131class RRPN(RPN):132    """133    Rotated Region Proposal Network described in :paper:`RRPN`.134    """135 136    @configurable137    def __init__(self, *args, **kwargs):138        super().__init__(*args, **kwargs)139        if self.anchor_boundary_thresh >= 0:140            raise NotImplementedError(141                "anchor_boundary_thresh is a legacy option not implemented for RRPN."142            )143 144    @classmethod145    def from_config(cls, cfg, input_shape: Dict[str, ShapeSpec]):146        ret = super().from_config(cfg, input_shape)147        ret["box2box_transform"] = Box2BoxTransformRotated(weights=cfg.MODEL.RPN.BBOX_REG_WEIGHTS)148        return ret149 150    @torch.no_grad()151    def label_and_sample_anchors(self, anchors: List[RotatedBoxes], gt_instances: List[Instances]):152        """153        Args:154            anchors (list[RotatedBoxes]): anchors for each feature map.155            gt_instances: the ground-truth instances for each image.156 157        Returns:158            list[Tensor]:159                List of #img tensors. i-th element is a vector of labels whose length is160                the total number of anchors across feature maps. Label values are in {-1, 0, 1},161                with meanings: -1 = ignore; 0 = negative class; 1 = positive class.162            list[Tensor]:163                i-th element is a Nx5 tensor, where N is the total number of anchors across164                feature maps.  The values are the matched gt boxes for each anchor.165                Values are undefined for those anchors not labeled as 1.166        """167        anchors = RotatedBoxes.cat(anchors)168 169        gt_boxes = [x.gt_boxes for x in gt_instances]170        del gt_instances171 172        gt_labels = []173        matched_gt_boxes = []174        for gt_boxes_i in gt_boxes:175            """176            gt_boxes_i: ground-truth boxes for i-th image177            """178            match_quality_matrix = retry_if_cuda_oom(pairwise_iou_rotated)(gt_boxes_i, anchors)179            matched_idxs, gt_labels_i = retry_if_cuda_oom(self.anchor_matcher)(match_quality_matrix)180            # Matching is memory-expensive and may result in CPU tensors. But the result is small181            gt_labels_i = gt_labels_i.to(device=gt_boxes_i.device)182 183            # A vector of labels (-1, 0, 1) for each anchor184            gt_labels_i = self._subsample_labels(gt_labels_i)185 186            if len(gt_boxes_i) == 0:187                # These values won't be used anyway since the anchor is labeled as background188                matched_gt_boxes_i = torch.zeros_like(anchors.tensor)189            else:190                # TODO wasted indexing computation for ignored boxes191                matched_gt_boxes_i = gt_boxes_i[matched_idxs].tensor192 193            gt_labels.append(gt_labels_i)  # N,AHW194            matched_gt_boxes.append(matched_gt_boxes_i)195        return gt_labels, matched_gt_boxes196 197    @torch.no_grad()198    def predict_proposals(self, anchors, pred_objectness_logits, pred_anchor_deltas, image_sizes):199        pred_proposals = self._decode_proposals(anchors, pred_anchor_deltas)200        return find_top_rrpn_proposals(201            pred_proposals,202            pred_objectness_logits,203            image_sizes,204            self.nms_thresh,205            self.pre_nms_topk[self.training],206            self.post_nms_topk[self.training],207            self.min_box_size,208            self.training,209        )210