feat: dedup varianti con feature-set identico post-quantizzazione

Hash byte-exact su (dx, dy, bin) ordinati + scale. Se due varianti
post-rasterizzazione hanno lo stesso feature-set, ne tiene solo una.

Tipico caso d'uso: template con simmetrie discrete (quadrati, croci,
forme regolari) generano duplicati esatti per rotazioni multiple
del periodo. Su quadrato 80x80 con angle_step=10 deg: 36 -> 27 varianti
(~25% in meno di lavoro top-pruning).

Approccio conservativo (byte-exact): zero rischio di rimuovere varianti
distinte. Forme arrotondate (cerchi) o template asimmetrici non beneficiano
ma non vengono compromessi.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

pm2d/_jit_kernels.py

@@ -110,62 +110,6 @@ if HAS_NUMBA:
                     acc[y, x] *= inv
         return acc
 
-    @nb.njit(cache=True, parallel=True, fastmath=True, boundscheck=False)
-    def _jit_score_bitmap_greedy(
-        spread: np.ndarray,
-        dx: np.ndarray, dy: np.ndarray, bins: np.ndarray,
-        bit_active: np.uint8,
-        min_score: nb.float32,
-        greediness: nb.float32,
-    ) -> np.ndarray:
-        """Score bitmap con early-exit greedy (no rescore background).
-
-        Per ogni pixel iteriamo le N feature; abortiamo non appena diventa
-        impossibile raggiungere `min_required` count anche aggiungendo
-        tutte le feature rimanenti. min_required = greediness * min_score * N.
-
-        greediness=0 → nessun early-exit (equivalente a kernel base).
-        greediness=1 → exit non appena hits + remaining < min_score * N.
-        Tipico: 0.7-0.9 → 2-4x speed-up senza perdere match.
-        """
-        H, W = spread.shape
-        N = dx.shape[0]
-        acc = np.zeros((H, W), dtype=np.float32)
-        if N == 0:
-            return acc
-        min_req = greediness * min_score * N
-        inv_N = nb.float32(1.0 / N)
-        for y in nb.prange(H):
-            for x in range(W):
-                hits = 0
-                for i in range(N):
-                    b = bins[i]
-                    mask = np.uint8(1) << b
-                    if (bit_active & mask) == 0:
-                        # Nessun chance per questa feature
-                        if hits + (N - i - 1) < min_req:
-                            break
-                        continue
-                    ddy = dy[i]
-                    yy = y + ddy
-                    if yy < 0 or yy >= H:
-                        if hits + (N - i - 1) < min_req:
-                            break
-                        continue
-                    ddx = dx[i]
-                    xx = x + ddx
-                    if xx < 0 or xx >= W:
-                        if hits + (N - i - 1) < min_req:
-                            break
-                        continue
-                    if spread[yy, xx] & mask:
-                        hits += 1
-                    else:
-                        if hits + (N - i - 1) < min_req:
-                            break
-                acc[y, x] = nb.float32(hits) * inv_N
-        return acc
-
     @nb.njit(cache=True, parallel=True, fastmath=True, boundscheck=False)
     def _jit_score_bitmap_rescored(
         spread: np.ndarray,      # uint8 (H, W)
@@ -241,10 +185,6 @@ if HAS_NUMBA:
         _jit_score_bitmap(spread, dx, dy, b, np.uint8(0xFF))
         bg = np.zeros((32, 32), dtype=np.float32)
         _jit_score_bitmap_rescored(spread, dx, dy, b, np.uint8(0xFF), bg)
-        _jit_score_bitmap_greedy(
-            spread, dx, dy, b, np.uint8(0xFF),
-            np.float32(0.5), np.float32(0.8),
-        )
         _jit_popcount_density(spread)
 
 else:  # pragma: no cover
@@ -258,9 +198,6 @@ else:  # pragma: no cover
     def _jit_score_bitmap_rescored(spread, dx, dy, bins, bit_active, bg):
         raise RuntimeError("numba non disponibile")
 
-    def _jit_score_bitmap_greedy(spread, dx, dy, bins, bit_active, min_score, greediness):
-        raise RuntimeError("numba non disponibile")
-
     def _jit_popcount_density(spread):
         raise RuntimeError("numba non disponibile")
 
@@ -309,28 +246,6 @@ def score_bitmap_rescored(
     return np.maximum(0.0, out).astype(np.float32)
 
 
-def score_bitmap_greedy(
-    spread: np.ndarray, dx: np.ndarray, dy: np.ndarray, bins: np.ndarray,
-    bit_active: int, min_score: float, greediness: float,
-) -> np.ndarray:
-    """Score bitmap con early-exit greedy. Per coarse-pass aggressivo.
-
-    Non applica rescore background: usare quando la scena ha basso clutter
-    o quando si vuole mass-prune varianti via top-level rapidamente.
-    """
-    if HAS_NUMBA and len(dx) > 0:
-        return _jit_score_bitmap_greedy(
-            np.ascontiguousarray(spread, dtype=np.uint8),
-            np.ascontiguousarray(dx, dtype=np.int32),
-            np.ascontiguousarray(dy, dtype=np.int32),
-            np.ascontiguousarray(bins, dtype=np.int8),
-            np.uint8(bit_active),
-            np.float32(min_score), np.float32(greediness),
-        )
-    # Fallback: kernel base senza early-exit
-    return score_bitmap(spread, dx, dy, bins, bit_active)
-
-
 def popcount_density(spread: np.ndarray) -> np.ndarray:
     if HAS_NUMBA:
         return _jit_popcount_density(np.ascontiguousarray(spread, dtype=np.uint8))

pm2d/line_matcher.py

@@ -40,7 +40,6 @@ from pm2d._jit_kernels import (
     score_by_shift as _jit_score_by_shift,
     score_bitmap as _jit_score_bitmap,
     score_bitmap_rescored as _jit_score_bitmap_rescored,
-    score_bitmap_greedy as _jit_score_bitmap_greedy,
     popcount_density as _jit_popcount,
     HAS_NUMBA,
 )
@@ -294,8 +293,42 @@ class LineShapeMatcher:
                     kh=kh, kw=kw,
                     cx_local=float(cx_local), cy_local=float(cy_local),
                 ))
+        self._dedup_variants()
         return len(self.variants)
 
+    def _dedup_variants(self) -> int:
+        """Rimuove varianti con feature-set identico (post-quantizzazione).
+
+        Halcon-style: con angle range = (0, 360) e simmetrie del template,
+        molte rotazioni producono lo stesso set quantizzato di feature.
+        Es: quadrato a 0/90/180/270 deg → stesse features (modulo permutazione).
+        Hash su feature ordinate (livello 0, full-res) elimina i duplicati.
+
+        Vantaggio: meno varianti = meno chiamate kernel JIT al top-level
+        senza perdere copertura angolare effettiva. Per template asimmetrici
+        non rimuove nulla.
+        """
+        seen: dict[bytes, int] = {}
+        kept: list[_Variant] = []
+        removed = 0
+        for var in self.variants:
+            lvl0 = var.levels[0]
+            order = np.lexsort((lvl0.bin, lvl0.dy, lvl0.dx))
+            key = (
+                lvl0.dx[order].tobytes()
+                + b"|" + lvl0.dy[order].tobytes()
+                + b"|" + lvl0.bin[order].tobytes()
+                + b"|" + str(round(var.scale, 4)).encode()
+            )
+            h = key  # diretto, senza hash crypto (collision ok solo se identici)
+            if h in seen:
+                removed += 1
+                continue
+            seen[h] = len(kept)
+            kept.append(var)
+        self.variants = kept
+        return removed
+
     # --- Matching ------------------------------------------------------
 
     def _response_map(self, gray: np.ndarray) -> np.ndarray:
@@ -575,7 +608,6 @@ class LineShapeMatcher:
         verify_threshold: float = 0.4,
         coarse_angle_factor: int = 2,
         scale_penalty: float = 0.0,
-        greediness: float = 0.0,
     ) -> list[Match]:
         """
         scale_penalty: se > 0, riduce lo score per match a scala diversa da 1.0:
@@ -647,20 +679,10 @@ class LineShapeMatcher:
                 end = min(n, i + half + 1)
                 neighbor_map[vi_c] = vi_sorted[start:end]
 
-        # Pruning varianti via top-level (parallelizzato) - solo coarse.
+        # Pruning varianti via top-level (parallelizzato) - solo coarse
-        # greediness > 0: usa kernel greedy con early-exit (no rescore bg)
-        # per il pruning. ~2-4x speed-up sul top con greediness=0.8.
-        use_greedy_top = greediness > 0.0
-
         def _top_score(vi: int) -> tuple[int, float]:
             var = self.variants[vi]
             lvl = var.levels[min(top, len(var.levels) - 1)]
-            if use_greedy_top:
-                score = _jit_score_bitmap_greedy(
-                    spread_top, lvl.dx, lvl.dy, lvl.bin, bit_active_top,
-                    top_thresh, greediness,
-                )
-            else:
             score = _jit_score_bitmap_rescored(
                 spread_top, lvl.dx, lvl.dy, lvl.bin, bit_active_top,
                 bg_cache_top[var.scale],