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https://github.com/SikongJueluo/Mini-Nav.git
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- Add SoftwareCamIndex class with xnor_popcount_score for CAM-style matching - Add CamMatch and SceneGraphMatch dataclasses for query results - Add query_by_visual_hash method to SimpleSceneGraph - Add comprehensive tests for SoftwareCamIndex and xnor_popcount_score
85 lines
2.4 KiB
Python
85 lines
2.4 KiB
Python
from __future__ import annotations
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from dataclasses import dataclass
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from typing import TYPE_CHECKING
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from .hash_codec import DEFAULT_HASH_WIDTH, hash_bytes_to_cam_row
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if TYPE_CHECKING:
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from .scenegraph import SimpleSceneGraph
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def xnor_popcount_score(
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query_row: int,
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stored_row: int,
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*,
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width: int = DEFAULT_HASH_WIDTH,
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) -> int:
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"""Compute CAM-style same-bit score for two integer hash rows."""
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if width <= 0:
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raise ValueError("width must be greater than 0")
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mask = (1 << width) - 1
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return int((~(int(query_row) ^ int(stored_row)) & mask).bit_count())
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@dataclass(frozen=True)
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class CamMatch:
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row_index: int
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obj_id: str
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score: int
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similarity: float
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hash_bytes: bytes
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@dataclass(frozen=True)
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class SoftwareCamIndex:
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obj_ids: tuple[str, ...]
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rows: tuple[int, ...]
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hashes: tuple[bytes, ...]
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width: int = DEFAULT_HASH_WIDTH
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@classmethod
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def from_scene_graph(
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cls,
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scene_graph: "SimpleSceneGraph",
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*,
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width: int = DEFAULT_HASH_WIDTH,
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) -> "SoftwareCamIndex":
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obj_ids: list[str] = []
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rows: list[int] = []
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hashes: list[bytes] = []
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for obj_id, node in scene_graph.objects.items():
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hash_bytes = node.visual_hash
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obj_ids.append(obj_id)
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hashes.append(hash_bytes)
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rows.append(hash_bytes_to_cam_row(hash_bytes, width=width))
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return cls(
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obj_ids=tuple(obj_ids),
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rows=tuple(rows),
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hashes=tuple(hashes),
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width=width,
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)
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def query(self, query_hash_bytes: bytes, *, top_k: int = 1) -> list[CamMatch]:
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if top_k <= 0:
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raise ValueError("top_k must be greater than 0")
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if not self.rows:
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raise ValueError("cannot query an empty SoftwareCamIndex")
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query_row = hash_bytes_to_cam_row(query_hash_bytes, width=self.width)
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matches = [
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CamMatch(
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row_index=row_index,
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obj_id=self.obj_ids[row_index],
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score=score,
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similarity=score / float(self.width),
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hash_bytes=self.hashes[row_index],
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)
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for row_index, row in enumerate(self.rows)
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for score in [xnor_popcount_score(query_row, row, width=self.width)]
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]
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matches.sort(key=lambda match: (-match.score, match.row_index))
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return matches[: min(top_k, len(matches))]
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