更新 detacttracking

detecttracking/tracking/trackers/reid/model/metric.py

@@ -0,0 +1,83 @@
+# Definition of ArcFace loss and CosFace loss
+
+import math
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+
+
+class ArcFace(nn.Module):
+    
+    def __init__(self, embedding_size, class_num, s=30.0, m=0.50):
+        """ArcFace formula: 
+            cos(m + theta) = cos(m)cos(theta) - sin(m)sin(theta)
+        Note that:
+            0 <= m + theta <= Pi
+        So if (m + theta) >= Pi, then theta >= Pi - m. In [0, Pi]
+        we have:
+            cos(theta) < cos(Pi - m)
+        So we can use cos(Pi - m) as threshold to check whether 
+        (m + theta) go out of [0, Pi]
+
+        Args:
+            embedding_size: usually 128, 256, 512 ...
+            class_num: num of people when training
+            s: scale, see normface https://arxiv.org/abs/1704.06369
+            m: margin, see SphereFace, CosFace, and ArcFace paper
+        """
+        super().__init__()
+        self.in_features = embedding_size
+        self.out_features = class_num
+        self.s = s
+        self.m = m
+        self.weight = nn.Parameter(torch.FloatTensor(class_num, embedding_size))
+        nn.init.xavier_uniform_(self.weight)
+
+        self.cos_m = math.cos(m)
+        self.sin_m = math.sin(m)
+        self.th = math.cos(math.pi - m)
+        self.mm = math.sin(math.pi - m) * m
+
+    def forward(self, input, label):
+        #print(f"embding {self.in_features}, class_num {self.out_features}, input {len(input)}, label {len(label)}")
+        cosine = F.linear(F.normalize(input), F.normalize(self.weight))
+        # print('F.normalize(input)',input.shape)
+        # print('F.normalize(self.weight)',F.normalize(self.weight).shape)
+        sine = ((1.0 - cosine.pow(2)).clamp(0, 1)).sqrt()
+        phi = cosine * self.cos_m - sine * self.sin_m
+        phi = torch.where(cosine > self.th, phi, cosine - self.mm)  # drop to CosFace
+        #print(f'consine {cosine.shape, cosine}, sine {sine.shape, sine}, phi {phi.shape, phi}')
+        # update y_i by phi in cosine
+        output = cosine * 1.0  # make backward works
+        batch_size = len(output)
+        output[range(batch_size), label] = phi[range(batch_size), label]
+        # print(f'output {(output * self.s).shape}')
+        # print(f'phi[range(batch_size), label] {phi[range(batch_size), label]}')
+        return output * self.s
+
+
+class CosFace(nn.Module):
+
+    def __init__(self, in_features, out_features, s=30.0, m=0.40):
+        """
+        Args:
+            embedding_size: usually 128, 256, 512 ...
+            class_num: num of people when training
+            s: scale, see normface https://arxiv.org/abs/1704.06369
+            m: margin, see SphereFace, CosFace, and ArcFace paper
+        """
+        super().__init__()
+        self.in_features = in_features
+        self.out_features = out_features
+        self.s = s
+        self.m = m
+        self.weight = nn.Parameter(torch.FloatTensor(out_features, in_features))
+        nn.init.xavier_uniform_(self.weight)
+
+    def forward(self, input, label):
+        cosine = F.linear(F.normalize(input), F.normalize(self.weight))
+        phi = cosine - self.m
+        output = cosine * 1.0  # make backward works
+        batch_size = len(output)
+        output[range(batch_size), label] = phi[range(batch_size), label]
+        return output * self.s