douyin-captcha/try/method_j_objects.py

"""方法J：低饱和度暗色几何对象检测 + alpha 轮廓匹配。

样本中的 mark 不是用于 RGB 像素复制，而是一个透明几何图形；背景中对应
对象通常是低饱和度、较暗的半透明图形。先用多组局部暗度/饱和度阈值提取
物体级连通区域，再用 mark 的 alpha 外轮廓进行形状筛选。
"""
from pathlib import Path
import math
import cv2
import numpy as np

ROOT = Path(__file__).resolve().parent.parent
CAP = ROOT / "captchas"
OUT = ROOT / "try" / "out" / "J"
OUT.mkdir(parents=True, exist_ok=True)

DARK_THRESHOLDS = (8, 12, 16, 20, 25, 30, 40, 50)
SAT_THRESHOLDS = (50, 70, 90, 110, 140)
TOP_K = 5
MIN_SIDE, MAX_SIDE = 25, 220


def files_for(prefix):
    bigs = [p for p in CAP.glob(f"{prefix}*.jpeg") if "-mark" not in p.stem]
    if not bigs:
        return None, None
    big = bigs[0]
    return big, CAP / f"{big.stem}-mark.png"


def mark_data(path):
    try:
        mark = cv2.imread(str(path), cv2.IMREAD_UNCHANGED)
        if mark is None:
            return None
        alpha = mark[..., 3] if mark.ndim == 3 and mark.shape[2] == 4 else np.full(mark.shape[:2], 255, np.uint8)
        mask = (alpha > 128).astype(np.uint8) * 255
        contours, _ = cv2.findContours(mask, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)
        if not contours:
            return None
        contour = max(contours, key=cv2.contourArea)
        x, y, w, h = cv2.boundingRect(contour)
        area = max(float(cv2.contourArea(contour)), 1.0)
        return contour, area, (x, y, w, h)
    except Exception as e:
        print(f"  mark 读取失败: {e}")
        return None


def segmentation_masks(bgr):
    gray = cv2.cvtColor(bgr, cv2.COLOR_BGR2GRAY)
    hsv = cv2.cvtColor(bgr, cv2.COLOR_BGR2HSV)
    local = cv2.GaussianBlur(gray, (0, 0), 21)
    dark_delta = np.clip(local.astype(np.int16) - gray.astype(np.int16), 0, 255).astype(np.uint8)
    for dt in DARK_THRESHOLDS:
        for st in SAT_THRESHOLDS:
            mask = ((dark_delta >= dt) & (hsv[..., 1] <= st)).astype(np.uint8) * 255
            mask = cv2.morphologyEx(mask, cv2.MORPH_CLOSE, np.ones((5, 5), np.uint8), iterations=2)
            yield mask, dt, st


def contour_metrics(mark_contour, mark_area, contour, gray):
    try:
        x, y, w, h = cv2.boundingRect(contour)
        if min(w, h) < MIN_SIDE or max(w, h) > MAX_SIDE:
            return None
        area = float(cv2.contourArea(contour))
        if area < mark_area * 0.04:
            return None
        shape = float(cv2.matchShapes(mark_contour, contour, cv2.CONTOURS_MATCH_I1, 0.0))
        perimeter = max(float(cv2.arcLength(contour, True)), 1.0)
        compact = min(1.0, 4.0 * math.pi * area / perimeter**2)
        hull = cv2.convexHull(contour)
        hull_area = max(float(cv2.contourArea(hull)), 1.0)
        solidity = min(1.0, area / hull_area)
        aspect = min(w, h) / max(w, h)
        # 几何图形一般轮廓完整、实心度较高；照片纹理多为细长碎片。
        if compact < 0.08 or solidity < 0.25:
            return None
        inside = gray[y:y + h, x:x + w]
        contrast = float(inside.std()) if inside.size else 0.0
        return shape, -compact, -solidity, -aspect, -contrast, (x, y, w, h)
    except cv2.error:
        return None


def overlap(box1, box2):
    try:
        x1, y1, w1, h1 = box1
        x2, y2, w2, h2 = box2
        ix = max(0, min(x1 + w1, x2 + w2) - max(x1, x2))
        iy = max(0, min(y1 + h1, y2 + h2) - max(y1, y2))
        inter = ix * iy
        union = w1 * h1 + w2 * h2 - inter
        return inter / union if union else 0.0
    except Exception:
        return 0.0


def process(prefix, lines):
    try:
        big_path, mark_path = files_for(prefix)
        if big_path is None:
            return
        bgr = cv2.imread(str(big_path), cv2.IMREAD_COLOR)
        md = mark_data(mark_path)
        if bgr is None or md is None:
            lines.append(f"{prefix}\tSKIP\t读取失败")
            return
        mark_contour, mark_area, _ = md
        gray = cv2.cvtColor(bgr, cv2.COLOR_BGR2GRAY)
        candidates = []
        for mask, dt, st in segmentation_masks(bgr):
            contours, _ = cv2.findContours(mask, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)
            for contour in contours:
                metric = contour_metrics(mark_contour, mark_area, contour, gray)
                if metric is None:
                    continue
                shape, neg_compact, neg_solidity, neg_aspect, neg_contrast, box = metric
                if any(overlap(box, old[6]) > 0.6 for old in candidates):
                    continue
                candidates.append((shape, neg_compact, neg_solidity, neg_aspect,
                                   neg_contrast, (dt, st), box))
        candidates.sort(key=lambda c: (c[0], c[1], c[2], c[3]))
        candidates = candidates[:TOP_K]
        if not candidates:
            lines.append(f"{prefix}\tSKIP\t无候选")
            return
        best = candidates[0]
        shape, neg_compact, neg_solidity, neg_aspect, neg_contrast, ts, box = best
        x, y, w, h = box
        print(f"{prefix}  shape={shape:.4f} compact={-neg_compact:.3f} solidity={-neg_solidity:.3f} "
              f"aspect={-neg_aspect:.3f} offset=({x},{y}) size=({w},{h}) threshold={ts}")
        lines.append(f"{prefix}\tshape={shape:.4f}\tcompact={-neg_compact:.3f}\t"
                     f"solidity={-neg_solidity:.3f}\taspect={-neg_aspect:.3f}\t"
                     f"offset=({x},{y})\tsize=({w},{h})\tthreshold={ts}")
        vis = bgr.copy()
        for i, item in enumerate(candidates):
            _, _, _, _, _, _, (px, py, pw, ph) = item
            color = (0, 0, 255) if i == 0 else (255, 0, 0)
            cv2.rectangle(vis, (px, py), (px + pw, py + ph), color, 2)
            cv2.putText(vis, str(i + 1), (px + 2, py + 16), cv2.FONT_HERSHEY_SIMPLEX, .55, color, 2)
        cv2.imwrite(str(OUT / f"{prefix}-match.png"), vis)
    except Exception as e:
        print(f"{prefix}  处理失败: {e}")
        lines.append(f"{prefix}\tERROR\t{e}")


def main():
    lines = []
    prefixes = sorted({p.name.split("~", 1)[0] for p in CAP.glob("*.jpeg") if "-mark" not in p.stem})
    for prefix in prefixes:
        process(prefix, lines)
    (OUT / "summary.txt").write_text("\n".join(lines) + "\n", encoding="utf-8")
    print(f"\n结果已写入 {OUT}/")


if __name__ == "__main__":
    main()