File size: 5,742 Bytes
c8a32e7
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
from itertools import repeat
from typing import List, Optional, Dict

import pypdfium2 as pdfium
import io
from concurrent.futures import ThreadPoolExecutor

from surya.ocr import run_recognition

from marker.models import setup_recognition_model
from marker.ocr.heuristics import should_ocr_page, no_text_found, detect_bad_ocr
from marker.ocr.lang import langs_to_ids
from marker.pdf.images import render_image
from marker.schema.page import Page
from marker.schema.block import Block, Line, Span
from marker.settings import settings
from marker.pdf.extract_text import get_text_blocks


def get_batch_size():
    if settings.RECOGNITION_BATCH_SIZE is not None:
        return settings.RECOGNITION_BATCH_SIZE
    elif settings.TORCH_DEVICE_MODEL == "cuda":
        return 32
    elif settings.TORCH_DEVICE_MODEL == "mps":
        return 32
    return 32


def run_ocr(doc, pages: List[Page], langs: List[str], rec_model, batch_multiplier=1) -> (List[Page], Dict):
    ocr_pages = 0
    ocr_success = 0
    ocr_failed = 0
    no_text = no_text_found(pages)
    ocr_idxs = []
    for pnum, page in enumerate(pages):
        ocr_needed = should_ocr_page(page, no_text)
        if ocr_needed:
            ocr_idxs.append(pnum)
            ocr_pages += 1

    # No pages need OCR
    if ocr_pages == 0:
        return pages, {"ocr_pages": 0, "ocr_failed": 0, "ocr_success": 0, "ocr_engine": "none"}

    ocr_method = settings.OCR_ENGINE
    if ocr_method is None:
        return pages, {"ocr_pages": 0, "ocr_failed": 0, "ocr_success": 0, "ocr_engine": "none"}
    elif ocr_method == "surya":
        # Load model just in time if we're not OCRing everything
        del_rec_model = False
        if rec_model is None:
            lang_tokens = langs_to_ids(langs)
            rec_model = setup_recognition_model(lang_tokens)
            del_rec_model = True

        new_pages = surya_recognition(doc, ocr_idxs, langs, rec_model, pages, batch_multiplier=batch_multiplier)

        if del_rec_model:
            del rec_model
    elif ocr_method == "ocrmypdf":
        new_pages = tesseract_recognition(doc, ocr_idxs, langs)
    else:
        raise ValueError(f"Unknown OCR method {ocr_method}")

    for orig_idx, page in zip(ocr_idxs, new_pages):
        if detect_bad_ocr(page.prelim_text) or len(page.prelim_text) == 0:
            ocr_failed += 1
        else:
            ocr_success += 1
            pages[orig_idx] = page

    return pages, {"ocr_pages": ocr_pages, "ocr_failed": ocr_failed, "ocr_success": ocr_success, "ocr_engine": ocr_method}


def surya_recognition(doc, page_idxs, langs: List[str], rec_model, pages: List[Page], batch_multiplier=1) -> List[Optional[Page]]:
    images = [render_image(doc[pnum], dpi=settings.SURYA_OCR_DPI) for pnum in page_idxs]
    processor = rec_model.processor
    selected_pages = [p for i, p in enumerate(pages) if i in page_idxs]

    surya_langs = [langs] * len(page_idxs)
    detection_results = [p.text_lines.bboxes for p in selected_pages]
    polygons = [[b.polygon for b in bboxes] for bboxes in detection_results]

    results = run_recognition(images, surya_langs, rec_model, processor, polygons=polygons, batch_size=get_batch_size() * batch_multiplier)

    new_pages = []
    for (page_idx, result, old_page) in zip(page_idxs, results, selected_pages):
        text_lines = old_page.text_lines
        ocr_results = result.text_lines
        blocks = []
        for i, line in enumerate(ocr_results):
            block = Block(
                bbox=line.bbox,
                pnum=page_idx,
                lines=[Line(
                    bbox=line.bbox,
                    spans=[Span(
                        text=line.text,
                        bbox=line.bbox,
                        span_id=f"{page_idx}_{i}",
                        font="",
                        font_weight=0,
                        font_size=0,
                    )
                    ]
                )]
            )
            blocks.append(block)
        page = Page(
            blocks=blocks,
            pnum=page_idx,
            bbox=result.image_bbox,
            rotation=0,
            text_lines=text_lines,
            ocr_method="surya"
        )
        new_pages.append(page)
    return new_pages


def tesseract_recognition(doc, page_idxs, langs: List[str]) -> List[Optional[Page]]:
    pdf_pages = generate_single_page_pdfs(doc, page_idxs)
    with ThreadPoolExecutor(max_workers=settings.OCR_PARALLEL_WORKERS) as executor:
        pages = list(executor.map(_tesseract_recognition, pdf_pages, repeat(langs, len(pdf_pages))))

    return pages


def generate_single_page_pdfs(doc, page_idxs) -> List[io.BytesIO]:
    pdf_pages = []
    for page_idx in page_idxs:
        blank_doc = pdfium.PdfDocument.new()
        blank_doc.import_pages(doc, pages=[page_idx])
        assert len(blank_doc) == 1, "Failed to import page"

        in_pdf = io.BytesIO()
        blank_doc.save(in_pdf)
        in_pdf.seek(0)
        pdf_pages.append(in_pdf)
    return pdf_pages


def _tesseract_recognition(in_pdf, langs: List[str]) -> Optional[Page]:
    import ocrmypdf
    out_pdf = io.BytesIO()

    ocrmypdf.ocr(
        in_pdf,
        out_pdf,
        language=langs[0],
        output_type="pdf",
        redo_ocr=None,
        force_ocr=True,
        progress_bar=False,
        optimize=False,
        fast_web_view=1e6,
        skip_big=15,  # skip images larger than 15 megapixels
        tesseract_timeout=settings.TESSERACT_TIMEOUT,
        tesseract_non_ocr_timeout=settings.TESSERACT_TIMEOUT,
    )

    new_doc = pdfium.PdfDocument(out_pdf.getvalue())

    blocks, _ = get_text_blocks(new_doc, max_pages=1)
    page = blocks[0]
    page.ocr_method = "tesseract"
    return page