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RoI，局部标签也要跟着换","sha256":"f91f197245559b3bae626926f71e4f9b53711f4d12e5bbf54e22afd917285c02","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":"reading-opening","title":"同一只杯子换了 RoI，局部标签也要跟着换","number":1},"sectionTitle":"同一只杯子换了 RoI，局部标签也要跟着换","currentQuestion":"同一只杯子换了 RoI，局部标签也要跟着换","sourceSlides":[],"knowledgeBlock":null,"formulas":[],"previousBlock":null,"nextBlock":"b-130d64e54b77ed8449bfdfb3","prerequisites":[{"id":"b-130d64e54b77ed8449bfdfb3","url":"#b-130d64e54b77ed8449bfdfb3","role":"problem-context"}],"relatedBlocks":[{"id":"b-3e88b35a4d4f619a5071d310","url":"#b-3e88b35a4d4f619a5071d310","relation":"figure-and-explanation"}]},{"id":"b-130d64e54b77ed8449bfdfb3","type":"p","scope":"local-mask-coordinate-target","url":"https://codingai-lec03.pages.dev/course/blocks/local-mask-coordinate-target.html#b-130d64e54b77ed8449bfdfb3","content":"同一个对象在两个 RoI 中的局部位置不同，因此训练 target 必须与区域坐标同步。这里连接实际 mask 对应与原论文的 RoIAlign 实证；接下来固定 F 的问卷反例改变了实验条件，不否定这个正面结果。","sha256":"3977c7392857965e1a19004cc5840b9c307e8ffb38cd9a25fdc49f2668ef3bac","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":"reading-opening","title":"同一只杯子换了 RoI，局部标签也要跟着换","number":1},"sectionTitle":"同一只杯子换了 RoI，局部标签也要跟着换","currentQuestion":"同一只杯子换了 RoI，局部标签也要跟着换","sourceSlides":[],"knowledgeBlock":null,"formulas":[],"previousBlock":"b-d26bbeda70a6ec98b764690e","nextBlock":"b-d4cc0c91a7f255171422b58a","prerequisites":[{"id":"b-d26bbeda70a6ec98b764690e","url":"#b-d26bbeda70a6ec98b764690e","role":"section-title"}],"relatedBlocks":[{"id":"b-3e88b35a4d4f619a5071d310","url":"#b-3e88b35a4d4f619a5071d310","relation":"figure-and-explanation"}]},{"id":"b-d4cc0c91a7f255171422b58a","type":"p","scope":"local-mask-coordinate-target","url":"https://codingai-lec03.pages.dev/course/blocks/local-mask-coordinate-target.html#b-d4cc0c91a7f255171422b58a","content":"原图位置 $(x,y)$ 在框 $b=(x_0,y_0,w,h)$ 内，可写成相对位置 $((x-x_0)/w,(y-y_0)/h)$。杯子本身不动，框变宽后，杯子占局部窗口的比例会变小；框向右偏，杯子在局部窗口中会向左移动。","sha256":"2285661c2adcbbd0aedc0360bef8e00ea325e04ae0a5536a273779b9b116ad62","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":"reading-opening","title":"同一只杯子换了 RoI，局部标签也要跟着换","number":1},"sectionTitle":"同一只杯子换了 RoI，局部标签也要跟着换","currentQuestion":"同一只杯子换了 RoI，局部标签也要跟着换","sourceSlides":[],"knowledgeBlock":null,"formulas":[{"latex":"(x,y)","definitionContext":"同一只杯子换了 RoI，局部标签也要跟着换"},{"latex":"b=(x_0,y_0,w,h)","definitionContext":"同一只杯子换了 RoI，局部标签也要跟着换"},{"latex":"((x-x_0)/w,(y-y_0)/h)","definitionContext":"同一只杯子换了 RoI，局部标签也要跟着换"}],"previousBlock":"b-130d64e54b77ed8449bfdfb3","nextBlock":"b-575195b32112cf10a78048f3","prerequisites":[{"id":"b-d26bbeda70a6ec98b764690e","url":"#b-d26bbeda70a6ec98b764690e","role":"section-title"},{"id":"b-130d64e54b77ed8449bfdfb3","url":"#b-130d64e54b77ed8449bfdfb3","role":"problem-context"}],"relatedBlocks":[{"id":"b-3e88b35a4d4f619a5071d310","url":"#b-3e88b35a4d4f619a5071d310","relation":"figure-and-explanation"}]},{"id":"b-575195b32112cf10a78048f3","type":"p","scope":"local-mask-coordinate-target","url":"https://codingai-lec03.pages.dev/course/blocks/local-mask-coordinate-target.html#b-575195b32112cf10a78048f3","content":"因此局部 mask 不只取决于对象轮廓，还取决于当前 RoI。训练时须将匹配实例的真值 mask 按同一框裁取并映射到目标网格；推理时再把局部预测映回该框的原图位置。若错把杯一的局部标签贴到杯二框上，网络收到的监督关系已经错了，增加参数不能补救这个对应错误。","sha256":"af9fc7a0404c564a4d7edee244af8e4ce3fb194116d1137f6b04e9426325128a","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":"reading-opening","title":"同一只杯子换了 RoI，局部标签也要跟着换","number":1},"sectionTitle":"同一只杯子换了 RoI，局部标签也要跟着换","currentQuestion":"同一只杯子换了 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RoIAlign。","sha256":"d81a07eea278a0c4a805de92844c3924f1ab5dff4a997cd7deb33fe85123cbe6","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":"reading-opening","title":"同一只杯子换了 RoI，局部标签也要跟着换","number":1},"sectionTitle":"同一只杯子换了 RoI，局部标签也要跟着换","currentQuestion":"同一只杯子换了 RoI，局部标签也要跟着换","sourceSlides":[],"knowledgeBlock":null,"formulas":[],"previousBlock":"b-575195b32112cf10a78048f3","nextBlock":"b-cf14850f220b411e2733509b","prerequisites":[{"id":"b-d26bbeda70a6ec98b764690e","url":"#b-d26bbeda70a6ec98b764690e","role":"section-title"},{"id":"b-130d64e54b77ed8449bfdfb3","url":"#b-130d64e54b77ed8449bfdfb3","role":"problem-context"}],"relatedBlocks":[{"id":"b-3e88b35a4d4f619a5071d310","url":"#b-3e88b35a4d4f619a5071d310","relation":"figure-and-explanation"}]},{"id":"b-cf14850f220b411e2733509b","type":"p","scope":"local-mask-coordinate-target","url":"https://codingai-lec03.pages.dev/course/blocks/local-mask-coordinate-target.html#b-cf14850f220b411e2733509b","content":"这也是原论文需要对齐消融的理由：实例 mask 对空间对应提出更严格要求。正面实验说明正确读取有实用收益；它与 P44 的均值碰撞不矛盾，因为两个实验固定的条件不同。","sha256":"c0d26bc67bed3d6f2c51f753a0c5fc838fff512108db877d29dfd223e14d69d5","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":"reading-opening","title":"同一只杯子换了 RoI，局部标签也要跟着换","number":1},"sectionTitle":"同一只杯子换了 RoI，局部标签也要跟着换","currentQuestion":"同一只杯子换了 RoI，局部标签也要跟着换","sourceSlides":[],"knowledgeBlock":null,"formulas":[],"previousBlock":"b-954d98d74c998973d79c82c0","nextBlock":"b-3e88b35a4d4f619a5071d310","prerequisites":[{"id":"b-d26bbeda70a6ec98b764690e","url":"#b-d26bbeda70a6ec98b764690e","role":"section-title"},{"id":"b-130d64e54b77ed8449bfdfb3","url":"#b-130d64e54b77ed8449bfdfb3","role":"problem-context"}],"relatedBlocks":[{"id":"b-3e88b35a4d4f619a5071d310","url":"#b-3e88b35a4d4f619a5071d310","relation":"figure-and-explanation"}]},{"id":"b-3e88b35a4d4f619a5071d310","type":"figure","scope":"local-mask-coordinate-target","url":"https://codingai-lec03.pages.dev/course/blocks/local-mask-coordinate-target.html#b-3e88b35a4d4f619a5071d310","content":"图内标签与数值：Lecture 03 课堂图解 P43；同一只杯子，两份 RoI；RoI A：更紧；局部目标占比更大；RoI B：更宽；轮廓更小，位置也改变；同一可见轮廓映射到不同局部坐标；区域范围、采样与 mask 目标必须一致。\n\n对象不变，局部框变化，归一化 mask 的位置和比例随之变化。 查看对应图解状态\n\n- 同一只杯子，两份 RoI\n- RoI A：更紧\n- 局部目标占比更大\n- RoI B：更宽\n- 轮廓更小，位置也改变\n- 同一可见轮廓映射到不同局部坐标；区域范围、采样与 mask 目标必须一致。对象不变，局部框变化，归一化 mask 的位置和比例随之变化。 [查看对应图解状态](/#/l3-r2-p43/0)[查看完整图解](/#/l3-r2-p43/0)","sha256":"7341f89c74efce28d5c815ee2ea181c231f9ee7fcedec3e1868d9e5f244c72e9","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":"reading-opening","title":"同一只杯子换了 RoI，局部标签也要跟着换","number":1},"sectionTitle":"同一只杯子换了 RoI，局部标签也要跟着换","currentQuestion":"同一只杯子换了 RoI，局部标签也要跟着换","sourceSlides":[],"knowledgeBlock":null,"formulas":[],"figure":{"caption":"对象不变，局部框变化，归一化 mask 的位置和比例随之变化。 查看对应图解状态","labels":["同一只杯子，两份 RoI","RoI A：更紧","局部目标占比更大","RoI B：更宽","轮廓更小，位置也改变","同一可见轮廓映射到不同局部坐标；区域范围、采样与 mask 目标必须一致。"],"description":"对象不变，局部框变化，归一化 mask 的位置和比例随之变化。 查看对应图解状态同一只杯子，两份 RoIRoI A：更紧局部目标占比更大RoI B：更宽轮廓更小，位置也改变同一可见轮廓映射到不同局部坐标；区域范围、采样与 mask 目标必须一致。","evidenceIdentity":"对象不变，局部框变化，归一化 mask 的位置和比例随之变化。 查看对应图解状态","images":[{"src":"/assets/display/8ced939a1fd55047fbf73ea5.webp","alt":""}]},"previousBlock":"b-cf14850f220b411e2733509b","nextBlock":"b-62765496e01661909fc20ca0","prerequisites":[{"id":"b-d26bbeda70a6ec98b764690e","url":"#b-d26bbeda70a6ec98b764690e","role":"section-title"},{"id":"b-130d64e54b77ed8449bfdfb3","url":"#b-130d64e54b77ed8449bfdfb3","role":"problem-context"}],"relatedBlocks":[]},{"id":"b-62765496e01661909fc20ca0","type":"h2","scope":"local-mask-coordinate-target","url":"https://codingai-lec03.pages.dev/course/blocks/local-mask-coordinate-target.html#b-62765496e01661909fc20ca0","content":"## 继续阅读与实验","sha256":"2b9ccef7e1220e2250cceff1abd8bdd736b42f8da5a223f26b029f44b962e807","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":"reading-opening","title":"同一只杯子换了 RoI，局部标签也要跟着换","number":1},"sectionTitle":"同一只杯子换了 RoI，局部标签也要跟着换","currentQuestion":"同一只杯子换了 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