73 lines
2.0 KiB
Python
73 lines
2.0 KiB
Python
"""
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调度分类器模型
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轻量 CNN 分类器，用于判断验证码类型 (normal / math / 3d)。
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不同类型验证码视觉差异大，分类任务简单。
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架构: 4 层卷积 + GAP + FC
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输入: 灰度图 1×64×128
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输出: softmax 概率分布 (num_types 个类别)
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体积目标: < 500KB
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"""
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import torch
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import torch.nn as nn
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class CaptchaClassifier(nn.Module):
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"""
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轻量分类器。
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4 层卷积 (每层 Conv + BN + ReLU + MaxPool)
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→ 全局平均池化 → 全连接 → 输出类别数。
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"""
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def __init__(self, num_types: int = 3):
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super().__init__()
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self.num_types = num_types
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self.features = nn.Sequential(
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# block 1: 1 -> 16, 64x128 -> 32x64
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nn.Conv2d(1, 16, kernel_size=3, padding=1),
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nn.BatchNorm2d(16),
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nn.ReLU(inplace=True),
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nn.MaxPool2d(2, 2),
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# block 2: 16 -> 32, 32x64 -> 16x32
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nn.Conv2d(16, 32, kernel_size=3, padding=1),
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nn.BatchNorm2d(32),
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nn.ReLU(inplace=True),
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nn.MaxPool2d(2, 2),
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# block 3: 32 -> 64, 16x32 -> 8x16
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nn.Conv2d(32, 64, kernel_size=3, padding=1),
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nn.BatchNorm2d(64),
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nn.ReLU(inplace=True),
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nn.MaxPool2d(2, 2),
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# block 4: 64 -> 64, 8x16 -> 4x8
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nn.Conv2d(64, 64, kernel_size=3, padding=1),
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nn.BatchNorm2d(64),
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nn.ReLU(inplace=True),
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nn.MaxPool2d(2, 2),
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)
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# 全局平均池化 → 输出 (batch, 64, 1, 1)
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self.gap = nn.AdaptiveAvgPool2d(1)
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self.classifier = nn.Linear(64, num_types)
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def forward(self, x: torch.Tensor) -> torch.Tensor:
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"""
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Args:
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x: (batch, 1, 64, 128) 灰度图
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Returns:
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logits: (batch, num_types) 未经 softmax 的原始输出
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"""
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x = self.features(x)
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x = self.gap(x) # (B, 64, 1, 1)
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x = x.view(x.size(0), -1) # (B, 64)
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x = self.classifier(x) # (B, num_types)
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return x
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