🚧 dinglehopper: Compare line text directories (WIP)

qurator/dinglehopper/cli_line_dirs.py

@@ -0,0 +1,150 @@
+import os
+import sys
+import itertools
+
+import click
+from jinja2 import Environment, FileSystemLoader
+from markupsafe import escape
+from uniseg.graphemecluster import grapheme_clusters
+from ocrd_utils import initLogging
+
+from .character_error_rate import character_error_rate_n
+from .word_error_rate import word_error_rate_n, words_normalized
+from .align import seq_align
+from .extracted_text import ExtractedText
+from .ocr_files import plain_extract
+from .config import Config
+from .cli import gen_diff_report
+
+
+def all_equal(iterable):
+    g = itertools.groupby(iterable)
+    return next(g, True) and not next(g, False)
+
+
+def common_prefix(its):
+    return [p[0] for p in itertools.takewhile(all_equal, zip(*its))]
+
+
+def common_suffix(its):
+    return reversed(common_prefix(reversed(it) for it in its))
+
+
+def removesuffix(text, suffix):
+    if suffix and text.endswith(suffix):
+        return text[:-len(suffix)]
+    return text
+
+
+def process(gt_dir, ocr_dir, report_prefix, *, metrics=True):
+    gt_suffix = "".join(common_suffix(os.listdir(gt_dir)))
+    ocr_suffix = "".join(common_suffix(os.listdir(ocr_dir)))
+
+    cer = None
+    n_characters = None
+    char_diff_report = ""
+
+    for gt in os.listdir(gt_dir):
+        # Find a match by replacing the suffix
+        ocr = removesuffix(gt, gt_suffix) + ocr_suffix
+
+        gt_text = plain_extract(os.path.join(gt_dir, gt))
+        ocr_text = plain_extract(os.path.join(ocr_dir, ocr))
+
+        # Compute CER
+        l_cer, l_n_characters = character_error_rate_n(gt_text, ocr_text)
+        if cer is None:
+            cer, n_characters = l_cer, l_n_characters
+        else:
+            # Rolling update
+            cer = (cer * n_characters + l_cer * l_n_characters) / (n_characters + l_n_characters)
+            n_characters = n_characters + l_n_characters
+
+        # Compute WER
+        # TODO wer, n_words = word_error_rate_n(gt_text, ocr_text)
+        wer = 9999; n_words = 0
+
+        char_diff_report += gen_diff_report(
+             gt_text, ocr_text, css_prefix="c", joiner="", none="·"
+        )
+
+        # TODO
+        #  gt_words = words_normalized(gt_text)
+        #  ocr_words = words_normalized(ocr_text)
+        #  word_diff_report = gen_diff_report(
+        #      gt_words, ocr_words, css_prefix="w", joiner=" ", none="⋯"
+        #  )
+        word_diff_report = "TODO"
+
+
+    # XXX this is a copy from cli.py
+    def json_float(value):
+        """Convert a float value to an JSON float.
+
+        This is here so that float('inf') yields "Infinity", not "inf".
+        """
+        if value == float("inf"):
+            return "Infinity"
+        elif value == float("-inf"):
+            return "-Infinity"
+        else:
+            return str(value)
+
+    env = Environment(
+        loader=FileSystemLoader(
+            os.path.join(os.path.dirname(os.path.realpath(__file__)), "templates")
+        )
+    )
+    env.filters["json_float"] = json_float
+
+    for report_suffix in (".html", ".json"):
+        template_fn = "report" + report_suffix + ".j2"
+        out_fn = report_prefix + report_suffix
+
+        template = env.get_template(template_fn)
+        template.stream(
+            gt=gt,
+            ocr=ocr,
+            cer=cer,
+            n_characters=n_characters,
+            wer=wer,
+            n_words=n_words,
+            char_diff_report=char_diff_report,
+            word_diff_report=word_diff_report,
+            metrics=metrics,
+        ).dump(out_fn)
+
+
+@click.command()
+@click.argument("gt", type=click.Path(exists=True))
+@click.argument("ocr", type=click.Path(exists=True))
+@click.argument("report_prefix", type=click.Path(), default="report")
+@click.option(
+    "--metrics/--no-metrics", default=True, help="Enable/disable metrics and green/red"
+)
+def main(gt, ocr, report_prefix, metrics):
+    """
+    Compare the GT line text directory against the OCR line text directory.
+
+    This assumes that the GT line text directory contains textfiles with a common
+    suffix like ".gt.txt", and the OCR line text directory contains textfiles with
+    a common suffix like ".some-ocr.txt". The text files also need to be paired,
+    i.e. the GT file "line001.gt.txt" needs to match a file "line001.some-ocr.txt"
+    in the OCT lines directory.
+
+    The GT and OCR directories are usually round truth line texts and the results of
+    an OCR software, but you may use dinglehopper to compare two OCR results. In
+    that case, use --no-metrics to disable the then meaningless metrics and also
+    change the color scheme from green/red to blue.
+
+    The comparison report will be written to $REPORT_PREFIX.{html,json}, where
+    $REPORT_PREFIX defaults to "report". The reports include the character error
+    rate (CER) and the word error rate (WER).
+
+    """
+    initLogging()
+    process(gt, ocr, report_prefix, metrics=metrics)
+
+
+if __name__ == "__main__":
+    main()

setup.py

@@ -26,6 +26,7 @@ setup(
     entry_points={
         "console_scripts": [
             "dinglehopper=qurator.dinglehopper.cli:main",
+            "dinglehopper-line-dirs=qurator.dinglehopper.cli_line_dirs:main",
             "dinglehopper-extract=qurator.dinglehopper.cli_extract:main",
             "ocrd-dinglehopper=qurator.dinglehopper.ocrd_cli:ocrd_dinglehopper",
         ]