Files
breakpilot-lehrer/klausur-service/backend/cv_review_pipeline.py
Benjamin Admin b2a0126f14 [split-required] Split remaining Python monoliths (Phase 1 continued)
klausur-service (7 monoliths):
- grid_editor_helpers.py (1,737 → 5 files: columns, filters, headers, zones)
- cv_cell_grid.py (1,675 → 7 files: build, legacy, streaming, merge, vocab)
- worksheet_editor_api.py (1,305 → 4 files: models, AI, reconstruct, routes)
- legal_corpus_ingestion.py (1,280 → 3 files: registry, chunking, ingestion)
- cv_review.py (1,248 → 4 files: pipeline, spell, LLM, barrel)
- cv_preprocessing.py (1,166 → 3 files: deskew, dewarp, barrel)
- rbac.py, admin_api.py, routes/eh.py remain (next batch)

backend-lehrer (1 monolith):
- classroom_engine/repository.py (1,705 → 7 files by domain)

All re-export barrels preserve backward compatibility.
Zero import errors verified.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-04-24 22:47:59 +02:00

431 lines
14 KiB
Python

"""
CV Review Pipeline — Multi-pass OCR, line alignment, LLM post-correction, and orchestration.
Stages 6-8 of the CV vocabulary pipeline plus the main orchestrator.
Lizenz: Apache 2.0 (kommerziell nutzbar)
DATENSCHUTZ: Alle Verarbeitung erfolgt lokal.
"""
import logging
import time
from typing import Any, Dict, List, Optional
import numpy as np
from cv_vocab_types import (
CV_PIPELINE_AVAILABLE,
PageRegion,
PipelineResult,
VocabRow,
)
from cv_preprocessing import (
deskew_image,
dewarp_image,
render_image_high_res,
render_pdf_high_res,
)
from cv_layout import (
analyze_layout,
create_layout_image,
create_ocr_image,
)
from cv_ocr_engines import (
_group_words_into_lines,
)
logger = logging.getLogger(__name__)
try:
import cv2
except ImportError:
cv2 = None # type: ignore[assignment]
try:
import pytesseract
from PIL import Image
except ImportError:
pytesseract = None # type: ignore[assignment]
Image = None # type: ignore[assignment,misc]
# =============================================================================
# Stage 6: Multi-Pass OCR
# =============================================================================
def ocr_region(ocr_img: np.ndarray, region: PageRegion, lang: str,
psm: int, fallback_psm: Optional[int] = None,
min_confidence: float = 40.0) -> List[Dict[str, Any]]:
"""Run Tesseract OCR on a specific region with given PSM.
Args:
ocr_img: Binarized full-page image.
region: Region to crop and OCR.
lang: Tesseract language string.
psm: Page Segmentation Mode.
fallback_psm: If confidence too low, retry with this PSM per line.
min_confidence: Minimum average confidence before fallback.
Returns:
List of word dicts with text, position, confidence.
"""
crop = ocr_img[region.y:region.y + region.height,
region.x:region.x + region.width]
if crop.size == 0:
return []
pil_img = Image.fromarray(crop)
config = f'--psm {psm} --oem 3'
try:
data = pytesseract.image_to_data(pil_img, lang=lang, config=config,
output_type=pytesseract.Output.DICT)
except Exception as e:
logger.warning(f"Tesseract failed for region {region.type}: {e}")
return []
words = []
for i in range(len(data['text'])):
text = data['text'][i].strip()
conf = int(data['conf'][i])
if not text or conf < 10:
continue
words.append({
'text': text,
'left': data['left'][i] + region.x,
'top': data['top'][i] + region.y,
'width': data['width'][i],
'height': data['height'][i],
'conf': conf,
'region_type': region.type,
})
if words and fallback_psm is not None:
avg_conf = sum(w['conf'] for w in words) / len(words)
if avg_conf < min_confidence:
logger.info(f"Region {region.type}: avg confidence {avg_conf:.0f}% < {min_confidence}%, "
f"trying fallback PSM {fallback_psm}")
words = _ocr_region_line_by_line(ocr_img, region, lang, fallback_psm)
return words
def _ocr_region_line_by_line(ocr_img: np.ndarray, region: PageRegion,
lang: str, psm: int) -> List[Dict[str, Any]]:
"""OCR a region line by line (fallback for low-confidence regions)."""
crop = ocr_img[region.y:region.y + region.height,
region.x:region.x + region.width]
if crop.size == 0:
return []
inv = cv2.bitwise_not(crop)
h_proj = np.sum(inv, axis=1)
threshold = np.max(h_proj) * 0.05 if np.max(h_proj) > 0 else 0
lines = []
in_text = False
line_start = 0
for y in range(len(h_proj)):
if h_proj[y] > threshold and not in_text:
line_start = y
in_text = True
elif h_proj[y] <= threshold and in_text:
if y - line_start > 5:
lines.append((line_start, y))
in_text = False
if in_text and len(h_proj) - line_start > 5:
lines.append((line_start, len(h_proj)))
all_words = []
config = f'--psm {psm} --oem 3'
for line_y_start, line_y_end in lines:
pad = 3
y1 = max(0, line_y_start - pad)
y2 = min(crop.shape[0], line_y_end + pad)
line_crop = crop[y1:y2, :]
if line_crop.size == 0:
continue
pil_img = Image.fromarray(line_crop)
try:
data = pytesseract.image_to_data(pil_img, lang=lang, config=config,
output_type=pytesseract.Output.DICT)
except Exception:
continue
for i in range(len(data['text'])):
text = data['text'][i].strip()
conf = int(data['conf'][i])
if not text or conf < 10:
continue
all_words.append({
'text': text,
'left': data['left'][i] + region.x,
'top': data['top'][i] + region.y + y1,
'width': data['width'][i],
'height': data['height'][i],
'conf': conf,
'region_type': region.type,
})
return all_words
def run_multi_pass_ocr(ocr_img: np.ndarray,
regions: List[PageRegion],
lang: str = "eng+deu") -> Dict[str, List[Dict]]:
"""Run OCR on each detected region with optimized settings."""
results: Dict[str, List[Dict]] = {}
_ocr_skip = {'header', 'footer', 'margin_top', 'margin_bottom', 'margin_left', 'margin_right'}
for region in regions:
if region.type in _ocr_skip:
continue
if region.type == 'column_en':
words = ocr_region(ocr_img, region, lang='eng', psm=4)
elif region.type == 'column_de':
words = ocr_region(ocr_img, region, lang='deu', psm=4)
elif region.type == 'column_example':
words = ocr_region(ocr_img, region, lang=lang, psm=6,
fallback_psm=7, min_confidence=40.0)
else:
words = ocr_region(ocr_img, region, lang=lang, psm=6)
results[region.type] = words
logger.info(f"OCR {region.type}: {len(words)} words")
return results
# =============================================================================
# Stage 7: Line Alignment -> Vocabulary Entries
# =============================================================================
def match_lines_to_vocab(ocr_results: Dict[str, List[Dict]],
regions: List[PageRegion],
y_tolerance_px: int = 25) -> List[VocabRow]:
"""Align OCR results from different columns into vocabulary rows."""
if 'column_en' not in ocr_results and 'column_de' not in ocr_results:
logger.info("match_lines_to_vocab: no column_en/column_de in OCR results, returning empty")
return []
en_lines = _group_words_into_lines(ocr_results.get('column_en', []), y_tolerance_px)
de_lines = _group_words_into_lines(ocr_results.get('column_de', []), y_tolerance_px)
ex_lines = _group_words_into_lines(ocr_results.get('column_example', []), y_tolerance_px)
def line_y_center(line: List[Dict]) -> float:
return sum(w['top'] + w['height'] / 2 for w in line) / len(line)
def line_text(line: List[Dict]) -> str:
return ' '.join(w['text'] for w in line)
def line_confidence(line: List[Dict]) -> float:
return sum(w['conf'] for w in line) / len(line) if line else 0
vocab_rows: List[VocabRow] = []
for en_line in en_lines:
en_y = line_y_center(en_line)
en_text = line_text(en_line)
en_conf = line_confidence(en_line)
if len(en_text.strip()) < 2:
continue
de_text = ""
de_conf = 0.0
best_de_dist = float('inf')
best_de_idx = -1
for idx, de_line in enumerate(de_lines):
dist = abs(line_y_center(de_line) - en_y)
if dist < y_tolerance_px and dist < best_de_dist:
best_de_dist = dist
best_de_idx = idx
if best_de_idx >= 0:
de_text = line_text(de_lines[best_de_idx])
de_conf = line_confidence(de_lines[best_de_idx])
ex_text = ""
ex_conf = 0.0
best_ex_dist = float('inf')
best_ex_idx = -1
for idx, ex_line in enumerate(ex_lines):
dist = abs(line_y_center(ex_line) - en_y)
if dist < y_tolerance_px and dist < best_ex_dist:
best_ex_dist = dist
best_ex_idx = idx
if best_ex_idx >= 0:
ex_text = line_text(ex_lines[best_ex_idx])
ex_conf = line_confidence(ex_lines[best_ex_idx])
avg_conf = en_conf
conf_count = 1
if de_conf > 0:
avg_conf += de_conf
conf_count += 1
if ex_conf > 0:
avg_conf += ex_conf
conf_count += 1
vocab_rows.append(VocabRow(
english=en_text.strip(),
german=de_text.strip(),
example=ex_text.strip(),
confidence=avg_conf / conf_count,
y_position=int(en_y),
))
# Handle multi-line wrapping in example column
matched_ex_ys = set()
for row in vocab_rows:
if row.example:
matched_ex_ys.add(row.y_position)
for ex_line in ex_lines:
ex_y = line_y_center(ex_line)
already_matched = any(abs(ex_y - y) < y_tolerance_px for y in matched_ex_ys)
if already_matched:
continue
best_row = None
best_dist = float('inf')
for row in vocab_rows:
dist = ex_y - row.y_position
if 0 < dist < y_tolerance_px * 3 and dist < best_dist:
best_dist = dist
best_row = row
if best_row:
continuation = line_text(ex_line).strip()
if continuation:
best_row.example = (best_row.example + " " + continuation).strip()
vocab_rows.sort(key=lambda r: r.y_position)
return vocab_rows
# =============================================================================
# Stage 8: Optional LLM Post-Correction
# =============================================================================
async def llm_post_correct(img: np.ndarray, vocab_rows: List[VocabRow],
confidence_threshold: float = 50.0,
enabled: bool = False) -> List[VocabRow]:
"""Optionally send low-confidence regions to Qwen-VL for correction."""
if not enabled:
return vocab_rows
logger.info(f"LLM post-correction skipped (not yet implemented)")
return vocab_rows
# =============================================================================
# Orchestrator
# =============================================================================
async def run_cv_pipeline(
pdf_data: Optional[bytes] = None,
image_data: Optional[bytes] = None,
page_number: int = 0,
zoom: float = 3.0,
enable_dewarp: bool = True,
enable_llm_correction: bool = False,
lang: str = "eng+deu",
) -> PipelineResult:
"""Run the complete CV document reconstruction pipeline."""
if not CV_PIPELINE_AVAILABLE:
return PipelineResult(error="CV pipeline not available (OpenCV or Tesseract missing)")
result = PipelineResult()
total_start = time.time()
try:
# Stage 1: Render
t = time.time()
if pdf_data:
img = render_pdf_high_res(pdf_data, page_number, zoom)
elif image_data:
img = render_image_high_res(image_data)
else:
return PipelineResult(error="No input data (pdf_data or image_data required)")
result.stages['render'] = round(time.time() - t, 2)
result.image_width = img.shape[1]
result.image_height = img.shape[0]
logger.info(f"Stage 1 (render): {img.shape[1]}x{img.shape[0]} in {result.stages['render']}s")
# Stage 2: Deskew
t = time.time()
img, angle = deskew_image(img)
result.stages['deskew'] = round(time.time() - t, 2)
logger.info(f"Stage 2 (deskew): {angle:.2f}\u00b0 in {result.stages['deskew']}s")
# Stage 3: Dewarp
if enable_dewarp:
t = time.time()
img, _dewarp_info = dewarp_image(img)
result.stages['dewarp'] = round(time.time() - t, 2)
# Stage 4: Dual image preparation
t = time.time()
ocr_img = create_ocr_image(img)
layout_img = create_layout_image(img)
result.stages['image_prep'] = round(time.time() - t, 2)
# Stage 5: Layout analysis
t = time.time()
regions = analyze_layout(layout_img, ocr_img)
result.stages['layout'] = round(time.time() - t, 2)
result.columns_detected = len([r for r in regions if r.type.startswith('column')])
logger.info(f"Stage 5 (layout): {result.columns_detected} columns in {result.stages['layout']}s")
# Stage 6: Multi-pass OCR
t = time.time()
ocr_results = run_multi_pass_ocr(ocr_img, regions, lang)
result.stages['ocr'] = round(time.time() - t, 2)
total_words = sum(len(w) for w in ocr_results.values())
result.word_count = total_words
logger.info(f"Stage 6 (OCR): {total_words} words in {result.stages['ocr']}s")
# Stage 7: Line alignment
t = time.time()
vocab_rows = match_lines_to_vocab(ocr_results, regions)
result.stages['alignment'] = round(time.time() - t, 2)
# Stage 8: Optional LLM correction
if enable_llm_correction:
t = time.time()
vocab_rows = await llm_post_correct(img, vocab_rows)
result.stages['llm_correction'] = round(time.time() - t, 2)
# Convert to output format
result.vocabulary = [
{
"english": row.english,
"german": row.german,
"example": row.example,
"confidence": round(row.confidence, 1),
}
for row in vocab_rows
if row.english or row.german
]
result.duration_seconds = round(time.time() - total_start, 2)
logger.info(f"CV Pipeline complete: {len(result.vocabulary)} entries in {result.duration_seconds}s")
except Exception as e:
logger.error(f"CV Pipeline error: {e}")
import traceback
logger.debug(traceback.format_exc())
result.error = str(e)
result.duration_seconds = round(time.time() - total_start, 2)
return result