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@@ -1,203 +0,0 @@
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-import math
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-import torch
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-import torch.nn as nn
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-
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-from ..basic.conv import ConvModule
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-
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-
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-class RetinaNetHead(nn.Module):
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- def __init__(self, cfg, in_dim, out_dim, num_classes, num_cls_head=1, num_reg_head=1, act_type='relu', norm_type='BN'):
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- super().__init__()
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- self.fmp_size = None
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- self.DEFAULT_SCALE_CLAMP = math.log(1000.0 / 16)
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- # ------------------ Basic parameters -------------------
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- self.cfg = cfg
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- self.in_dim = in_dim
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- self.num_classes = num_classes
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- self.num_cls_head=num_cls_head
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- self.num_reg_head=num_reg_head
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- self.act_type=act_type
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- self.norm_type=norm_type
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- self.stride = cfg['out_stride']
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- # ------------------ Anchor parameters -------------------
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- self.anchor_size = self.get_anchor_sizes(cfg) # [S, KA, 2]
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- self.num_anchors = self.anchor_size.shape[1]
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-
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- # ------------------ Network parameters -------------------
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- ## cls head
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- cls_heads = []
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- self.cls_head_dim = out_dim
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- for i in range(self.num_cls_head):
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- if i == 0:
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- cls_heads.append(
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- ConvModule(in_dim, self.cls_head_dim, k=3, p=1, s=1,
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- act_type=self.act_type,
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- norm_type=self.norm_type)
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- )
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- else:
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- cls_heads.append(
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- ConvModule(self.cls_head_dim, self.cls_head_dim, k=3, p=1, s=1,
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- act_type=self.act_type,
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- norm_type=self.norm_type)
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- )
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- ## reg head
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- reg_heads = []
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- self.reg_head_dim = out_dim
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- for i in range(self.num_reg_head):
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- if i == 0:
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- reg_heads.append(
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- ConvModule(in_dim, self.reg_head_dim, k=3, p=1, s=1,
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- act_type=self.act_type,
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- norm_type=self.norm_type)
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- )
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- else:
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- reg_heads.append(
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- ConvModule(self.reg_head_dim, self.reg_head_dim, k=3, p=1, s=1,
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- act_type=self.act_type,
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- norm_type=self.norm_type)
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- )
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- self.cls_heads = nn.Sequential(*cls_heads)
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- self.reg_heads = nn.Sequential(*reg_heads)
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-
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- ## pred layers
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- self.cls_pred = nn.Conv2d(self.cls_head_dim, num_classes * self.num_anchors, kernel_size=3, padding=1)
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- self.reg_pred = nn.Conv2d(self.reg_head_dim, 4 * self.num_anchors, kernel_size=3, padding=1)
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-
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- # init bias
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- self._init_layers()
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-
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- def _init_layers(self):
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- for module in [self.cls_heads, self.reg_heads, self.cls_pred, self.reg_pred]:
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- for layer in module.modules():
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- if isinstance(layer, nn.Conv2d):
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- torch.nn.init.normal_(layer.weight, mean=0, std=0.01)
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- torch.nn.init.constant_(layer.bias, 0)
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- if isinstance(layer, nn.GroupNorm):
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- torch.nn.init.constant_(layer.weight, 1)
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- torch.nn.init.constant_(layer.bias, 0)
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- # init the bias of cls pred
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- init_prob = 0.01
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- bias_value = -torch.log(torch.tensor((1. - init_prob) / init_prob))
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- torch.nn.init.constant_(self.cls_pred.bias, bias_value)
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-
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- def get_anchor_sizes(self, cfg):
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- basic_anchor_size = cfg['anchor_config']['basic_size']
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- anchor_aspect_ratio = cfg['anchor_config']['aspect_ratio']
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- anchor_area_scale = cfg['anchor_config']['area_scale']
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-
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- num_scales = len(basic_anchor_size)
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- num_anchors = len(anchor_aspect_ratio) * len(anchor_area_scale)
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- anchor_sizes = []
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- for size in basic_anchor_size:
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- for ar in anchor_aspect_ratio:
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- for s in anchor_area_scale:
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- ah, aw = size
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- area = ah * aw * s
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- anchor_sizes.append(
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- [torch.sqrt(torch.tensor(ar * area)),
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- torch.sqrt(torch.tensor(area / ar))]
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- )
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- # [S * KA, 2] -> [S, KA, 2]
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- anchor_sizes = torch.as_tensor(anchor_sizes).view(num_scales, num_anchors, 2)
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-
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- return anchor_sizes
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-
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- def get_anchors(self, level, fmp_size):
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- """
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- fmp_size: (List) [H, W]
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- """
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- # generate grid cells
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- fmp_h, fmp_w = fmp_size
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- # [KA, 2]
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- anchor_size = self.anchor_size[level]
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-
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- anchor_y, anchor_x = torch.meshgrid([torch.arange(fmp_h), torch.arange(fmp_w)])
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- # [H, W, 2] -> [HW, 2]
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- anchor_xy = torch.stack([anchor_x, anchor_y], dim=-1).float().view(-1, 2) + 0.5
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- # [HW, 2] -> [HW, 1, 2] -> [HW, KA, 2]
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- anchor_xy = anchor_xy[:, None, :].repeat(1, self.num_anchors, 1)
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- anchor_xy *= self.stride[level]
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-
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- # [KA, 2] -> [1, KA, 2] -> [HW, KA, 2]
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- anchor_wh = anchor_size[None, :, :].repeat(fmp_h*fmp_w, 1, 1)
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-
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- # [HW, KA, 4] -> [M, 4], M = HW x KA
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- anchor_boxes = torch.cat([anchor_xy, anchor_wh], dim=-1)
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- anchor_boxes = anchor_boxes.view(-1, 4)
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-
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- return anchor_boxes
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-
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- def decode_boxes(self, anchor_boxes, pred_reg):
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- """
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- anchor_boxes: (List[Tensor]) [1, M, 4] or [M, 4]
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- pred_reg: (List[Tensor]) [B, M, 4] or [M, 4]
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- """
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- # x = x_anchor + dx * w_anchor
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- # y = y_anchor + dy * h_anchor
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- pred_ctr_offset = pred_reg[..., :2] * anchor_boxes[..., 2:]
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- pred_ctr_xy = anchor_boxes[..., :2] + pred_ctr_offset
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-
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- # w = w_anchor * exp(tw)
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- # h = h_anchor * exp(th)
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- pred_dwdh = pred_reg[..., 2:]
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- pred_dwdh = torch.clamp(pred_dwdh, max=self.DEFAULT_SCALE_CLAMP)
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- pred_wh = anchor_boxes[..., 2:] * pred_dwdh.exp()
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-
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- # convert [x, y, w, h] -> [x1, y1, x2, y2]
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- pred_x1y1 = pred_ctr_xy - 0.5 * pred_wh
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- pred_x2y2 = pred_ctr_xy + 0.5 * pred_wh
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- pred_box = torch.cat([pred_x1y1, pred_x2y2], dim=-1)
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-
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- return pred_box
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-
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- def forward(self, pyramid_feats, mask=None):
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- all_masks = []
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- all_anchors = []
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- all_cls_preds = []
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- all_reg_preds = []
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- all_box_preds = []
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- for level, feat in enumerate(pyramid_feats):
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- # ------------------- Decoupled head -------------------
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- cls_feat = self.cls_heads(feat)
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- reg_feat = self.reg_heads(feat)
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-
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- # ------------------- Generate anchor box -------------------
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- B, _, H, W = cls_feat.size()
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- fmp_size = [H, W]
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- anchor_boxes = self.get_anchors(level, fmp_size) # [M, 4]
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- anchor_boxes = anchor_boxes.to(cls_feat.device)
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-
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- # ------------------- Predict -------------------
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- cls_pred = self.cls_pred(cls_feat)
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- reg_pred = self.reg_pred(reg_feat)
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-
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- # ------------------- Process preds -------------------
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- ## [B, C, H, W] -> [B, H, W, C] -> [B, M, C]
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- cls_pred = cls_pred.permute(0, 2, 3, 1).contiguous().view(B, -1, self.num_classes)
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- reg_pred = reg_pred.permute(0, 2, 3, 1).contiguous().view(B, -1, 4)
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- ## Decode bbox
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- box_pred = self.decode_boxes(anchor_boxes, reg_pred)
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- ## Adjust mask
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- if mask is not None:
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- # [B, H, W]
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- mask_i = torch.nn.functional.interpolate(mask[None].float(), size=[H, W]).bool()[0]
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- # [B, H, W] -> [B, M]
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- mask_i = mask_i.flatten(1)
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- # [B, HW] -> [B, HW, KA] -> [B, M], M= HW x KA
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- mask_i = mask_i[..., None].repeat(1, 1, self.num_anchors).flatten(1)
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-
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- all_masks.append(mask_i)
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-
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- all_anchors.append(anchor_boxes)
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- all_cls_preds.append(cls_pred)
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- all_reg_preds.append(reg_pred)
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- all_box_preds.append(box_pred)
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-
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- outputs = {"pred_cls": all_cls_preds, # List [B, M, C]
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- "pred_reg": all_reg_preds, # List [B, M, 4]
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- "pred_box": all_box_preds, # List [B, M, 4]
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- "anchors": all_anchors, # List [B, M, 2]
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- "strides": self.stride,
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- "mask": all_masks} # List [B, M,]
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-
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- return outputs
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