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35/16，再判断取整改变了什么","number":1},"sectionTitle":"先算 35/16，再判断取整改变了什么","currentQuestion":"从坐标、四邻插值到局部目标，再检查论文中的同条件证据。","sourceSlides":["l3-r2-p41"],"knowledgeBlock":null,"formulas":[],"previousBlock":"b-93e16e1184477a89e9e30cef","nextBlock":"b-0ab9ceb623ab9100d6671a5b","prerequisites":[{"id":"b-93e16e1184477a89e9e30cef","url":"#b-93e16e1184477a89e9e30cef","role":"section-title"},{"id":"b-0ab9ceb623ab9100d6671a5b","url":"#b-0ab9ceb623ab9100d6671a5b","role":"problem-context"}],"relatedBlocks":[{"id":"b-4b0e0fb58fa6fd8c936dde1d","url":"#b-4b0e0fb58fa6fd8c936dde1d","relation":"figure-and-explanation"}]},{"id":"b-0ab9ceb623ab9100d6671a5b","type":"p","scope":"document","url":"https://codingai-lec03.pages.dev/course/pages/l3-r2-p41.html#b-0ab9ceb623ab9100d6671a5b","content":"先固定简单坐标约定 x/stride，再看 35→2.1875→取整 2 所造成的位置变化。真实库的像素中心与边界设置必须另核对；本页的三个像素误差是指定算例，不是所有实现的固定偏差。","sha256":"a718447ea93e2a98352601e665677407f3818c09ddd5c66f56f9f973812016b5","chapter":{"id":"II","title":"区域、像素与实例"},"unit":{"id":"roi-alignment-and-evidence","title":"区域采样怎样保住几何对应？"},"page":{"id":"roi-coordinate-quantization","title":"先算 35/16，再判断取整改变了什么","number":1},"sectionTitle":"先算 35/16，再判断取整改变了什么","currentQuestion":"从坐标、四邻插值到局部目标，再检查论文中的同条件证据。","sourceSlides":["l3-r2-p41"],"knowledgeBlock":null,"formulas":[],"previousBlock":"b-606418f135e7c8a1a049c5fd","nextBlock":"b-4b0e0fb58fa6fd8c936dde1d","prerequisites":[{"id":"b-606418f135e7c8a1a049c5fd","url":"#b-606418f135e7c8a1a049c5fd","role":"section-title"}],"relatedBlocks":[{"id":"b-4b0e0fb58fa6fd8c936dde1d","url":"#b-4b0e0fb58fa6fd8c936dde1d","relation":"figure-and-explanation"}]},{"id":"b-4b0e0fb58fa6fd8c936dde1d","type":"figure","scope":"document","url":"https://codingai-lec03.pages.dev/course/pages/l3-r2-p41.html#b-4b0e0fb58fa6fd8c936dde1d","content":"图内标签与数值：Lecture 03 课堂图解 P41；约定：原图 x ÷ 16 → 特征坐标；原图 x；0；16；32；48；64；35；连续位置；35/16 = 2.1875；32；取整后；2 × 16 = 32；读的位置变了 3 个原图像素；坐标示意，不模拟各框架的半像素约定；RoIAlign 避免相关坐标量化。\n\n原图坐标轴上的 x=35 映射到 stride16 特征坐标 2.1875；量化到 2 时对回 x=32，明确三像素偏移。\n\n- 约定：原图 x ÷ 16 → 特征坐标\n- 原图 x\n- 0\n- 16\n- 32\n- 48\n- 64\n- 35\n- 连续位置\n- 35/16 = 2.1875\n- 32\n- 取整后\n- 2 × 16 = 32\n- 读的位置变了 3 个原图像素\n- 坐标示意，不模拟各框架的半像素约定；RoIAlign 避免相关坐标量化。原图坐标轴上的 x=35 映射到 stride16 特征坐标 2.1875；量化到 2 时对回 x=32，明确三像素偏移。 [查看对应图解状态](/#/l3-r2-p41/1)[查看完整图解](/course/figures/l3-r2-p41-1.html)","sha256":"56593f80c842ad0a79026cf4e8e7a77725471a463be9037bbbbda48e6975c85f","chapter":{"id":"II","title":"区域、像素与实例"},"unit":{"id":"roi-alignment-and-evidence","title":"区域采样怎样保住几何对应？"},"page":{"id":"roi-coordinate-quantization","title":"先算 35/16，再判断取整改变了什么","number":1},"sectionTitle":"先算 35/16，再判断取整改变了什么","currentQuestion":"从坐标、四邻插值到局部目标，再检查论文中的同条件证据。","sourceSlides":["l3-r2-p41"],"knowledgeBlock":null,"formulas":[],"figure":{"caption":"原图坐标轴上的 x=35 映射到 stride16 特征坐标 2.1875；量化到 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课堂讲述","sha256":"786ce10a6b32a492259a3dccd0a54e61cd41d28a34382fb7b5386c5f03b7ad69","chapter":{"id":"II","title":"区域、像素与实例"},"unit":{"id":"roi-alignment-and-evidence","title":"区域采样怎样保住几何对应？"},"page":{"id":"roi-coordinate-quantization","title":"先算 35/16，再判断取整改变了什么","number":1},"sectionTitle":"先算 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的关键，就是在区域提取中避免相关量化，并用连续位置采样。下一页让这个采样变成能算出来的东西。","sha256":"9357bce2827314f36c0e7626f5b2ce2223f0fb55c82381860553dfd348849c48","chapter":{"id":"II","title":"区域、像素与实例"},"unit":{"id":"roi-alignment-and-evidence","title":"区域采样怎样保住几何对应？"},"page":{"id":"roi-coordinate-quantization","title":"先算 35/16，再判断取整改变了什么","number":1},"sectionTitle":"先算 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之后，为什么不应急着取整","sha256":"0a553f669ddf2c9f3eee37754a1252f32be1782ca63e97c468382e81653a83ac","chapter":{"id":"II","title":"区域、像素与实例"},"unit":{"id":"roi-alignment-and-evidence","title":"区域采样怎样保住几何对应？"},"page":{"id":"roi-coordinate-quantization","title":"先算 35/16，再判断取整改变了什么","number":1},"sectionTitle":"35 除以 16 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