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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":"reading-opening","title":"35 除以 16 之后，为什么不应急着取整","number":1},"sectionTitle":"35 除以 16 之后，为什么不应急着取整","currentQuestion":"35 除以 16 之后，为什么不应急着取整","sourceSlides":[],"knowledgeBlock":null,"formulas":[],"previousBlock":"b-1b60f80d82340e461e6578c2","nextBlock":"b-0dec10d15823fcf8f754603b","prerequisites":[{"id":"b-1b60f80d82340e461e6578c2","url":"#b-1b60f80d82340e461e6578c2","role":"section-title"}],"relatedBlocks":[{"id":"b-5611e362655eeed0a23ada43","url":"#b-5611e362655eeed0a23ada43","relation":"figure-and-explanation"}]},{"id":"b-0dec10d15823fcf8f754603b","type":"p","scope":"roi-coordinate-conventions","url":"https://codingai-lec03.pages.dev/course/blocks/roi-coordinate-conventions.html#b-0dec10d15823fcf8f754603b","content":"本页采用教学约定 (u=x/s)，不额外加入像素中心偏移。原图 x=35、特征步长 s=16，得到 u=2.1875。若立即取整为 2，读到的位置就相当于原图 x=32；对分类可能仍包含相似内容，但细杯柄边缘已偏了三个像素。","sha256":"3a6e0fa6b3fb69b6a4d4de6248f5782cd7f6cd1526a9e83bee2a3e905e0a0cba","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":"35 除以 16 之后，为什么不应急着取整","number":1},"sectionTitle":"35 除以 16 之后，为什么不应急着取整","currentQuestion":"35 除以 16 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x/s。具体实现还可能约定像素中心、半像素偏移、对齐端点及边界外采样。对照库输出时必须先统一这些约定，不能把差异都归结为数值误差。课堂算例选择简单坐标，是为了单独看清连续位置与量化的差别。","sha256":"59f2fa5526dd244c1cd7f426fbb3f8548e2296a2b892bfb242e03e04c4bf3c4b","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":"35 除以 16 之后，为什么不应急着取整","number":1},"sectionTitle":"35 除以 16 之后，为什么不应急着取整","currentQuestion":"35 除以 16 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边界被取整，细小移动可能完全不改变读数，跨过阈值又会突然跳变。保留连续几何，再通过邻域插值得值，便能把这些连续变化传到区域读出。","sha256":"fdbcb0321317dac836713727d5d1e056dbca8a7014e9fb008fd017cbc37e9ebe","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":"35 除以 16 之后，为什么不应急着取整","number":1},"sectionTitle":"35 除以 16 之后，为什么不应急着取整","currentQuestion":"35 除以 16 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查看对应图解状态\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。x=35 对应连续位置 2.1875；取整改变了原图上的对应位置。 [查看对应图解状态](/#/l3-r2-p41/1)[查看完整图解](/#/l3-r2-p41/1)","sha256":"bb7b9ff3751e6730b95c9f4a442ebe759ac03b116b15e30b32f3362820027daa","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":"35 除以 16 之后，为什么不应急着取整","number":1},"sectionTitle":"35 除以 16 之后，为什么不应急着取整","currentQuestion":"35 除以 16 之后，为什么不应急着取整","sourceSlides":[],"knowledgeBlock":null,"formulas":[],"figure":{"caption":"x=35 对应连续位置 2.1875；取整改变了原图上的对应位置。 查看对应图解状态","labels":["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。"],"description":"x=35 对应连续位置 2.1875；取整改变了原图上的对应位置。 查看对应图解状态约定：原图 x ÷ 16 → 特征坐标原图 x01632486435连续位置35/16 = 2.187532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。","evidenceIdentity":"x=35 对应连续位置 2.1875；取整改变了原图上的对应位置。 查看对应图解状态","images":[]},"previousBlock":"b-af85614d2cb0270606d84c27","nextBlock":"b-33c73695d53b0b7243b235a5","prerequisites":[{"id":"b-1b60f80d82340e461e6578c2","url":"#b-1b60f80d82340e461e6578c2","role":"section-title"},{"id":"b-c9aa4a11a15db44f849fa32c","url":"#b-c9aa4a11a15db44f849fa32c","role":"problem-context"}],"relatedBlocks":[]},{"id":"b-33c73695d53b0b7243b235a5","type":"h2","scope":"roi-coordinate-conventions","url":"https://codingai-lec03.pages.dev/course/blocks/roi-coordinate-conventions.html#b-33c73695d53b0b7243b235a5","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":"35 除以 16 之后，为什么不应急着取整","number":1},"sectionTitle":"35 除以 16 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