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的阈值不是评价的阈值 · 实现代码","sourceSlides":[],"knowledgeBlock":null,"formulas":[],"previousBlock":"b-f52641b044ed347550e565b5","nextBlock":"b-2d0895dbcc868a200554df4d","prerequisites":[{"id":"b-2e9749f59990bb222cfe8400","url":"#b-2e9749f59990bb222cfe8400","role":"section-title"},{"id":"b-6578f9fcee5c90a384d21ae1","url":"#b-6578f9fcee5c90a384d21ae1","role":"problem-context"}],"relatedBlocks":[]},{"id":"b-2d0895dbcc868a200554df4d","type":"pre","scope":"document","url":"https://codingai-lec03.pages.dev/course/notebook-blocks/afc86821efbb4021940cb56bf27497ec.html#b-2d0895dbcc868a200554df4d","content":"```\ndef class_aware_nms(boxes, scores, classes, iou_threshold=0.50):\n    \"\"\"Keep a box unless a higher-scored kept box of SAME class has IoU > threshold.\n\n    Equality is retained. There is no extra confidence cutoff in this lab.\n    \"\"\"\n    boxes = boxes_xyxy(boxes)\n    scores, classes = np.asarray(scores, float), np.asarray(classes)\n    if scores.shape != (len(boxes),) or classes.shape != (len(boxes),):\n        raise ValueError(\"Scores/classes must have shape (N,)\")\n    if not np.isfinite(scores).all() or not 0 <= iou_threshold <= 1:\n        raise ValueError(\"Finite scores and an IoU threshold in [0,1] required\")\n    remaining = np.argsort(-scores, kind=\"stable\")\n    kept, suppressed = [], []\n    while len(remaining):\n        current, remaining = int(remaining[0]), remaining[1:]\n        kept.append(current)\n        overlap = box_iou(boxes[current:current + 1], boxes[remaining])[0]\n        remove = (classes[remaining] == classes[current]) & (overlap > iou_threshold)\n        for victim, iou_value in zip(remaining[remove], overlap[remove]):\n            suppressed.append({\"prediction\": int(victim + 1), \"by\": current + 1,\n                               \"iou\": float(iou_value), \"class\": int(classes[current])})\n        remaining = remaining[~remove]\n    return np.asarray(kept, dtype=int), suppressed\n\nprint(\"NMS keeps 1-based predictions:\", class_aware_nms(PRED, SCORES, CLASSES, NMS_THRESHOLD)[0] + 1)\n```","sha256":"3fe7a5b21556059e41c3b20e435ee8b99fad068a74ad2b7497818abdaa31bf92","chapter":{"id":"course","title":"5 · NMS 的阈值不是评价的阈值 · 实现代码"},"unit":{"id":"notebook-blocks/afc86821efbb4021940cb56bf27497ec","title":"5 · NMS 的阈值不是评价的阈值 · 实现代码"},"page":{"id":"reading-opening","title":"5 · NMS 的阈值不是评价的阈值 · 实现代码","number":1},"sectionTitle":"5 · NMS 的阈值不是评价的阈值 · 实现代码","currentQuestion":"5 · NMS 的阈值不是评价的阈值 · 实现代码","sourceSlides":[],"knowledgeBlock":null,"formulas":[],"previousBlock":"b-e73cf5bf8a9cf82c3051b6b0","nextBlock":null,"prerequisites":[{"id":"b-2e9749f59990bb222cfe8400","url":"#b-2e9749f59990bb222cfe8400","role":"section-title"},{"id":"b-6578f9fcee5c90a384d21ae1","url":"#b-6578f9fcee5c90a384d21ae1","role":"problem-context"}],"relatedBlocks":[]}]}