nopaque/vre_ocr_node/ocr

#!/usr/bin/env python2
# coding=utf-8

"""
ocr

Usage:  For usage instructions run with option --help
Author: Patrick Jentsch <p.jentsch@uni-bielefeld.de>
"""


import argparse
import multiprocessing
import os
import sys
from pyflow import WorkflowRunner



def parse_arguments():
    parser = argparse.ArgumentParser(
        "Performs OCR of documents utilizing Tesseract OCR. \
        Outputs are .pdf and .txt."
    )

    parser.add_argument("-i",
                        dest="inputDir",
                        help="Input directory.",
                        required=True)
    parser.add_argument("-l",
                        dest='lang',
                        help="Language for OCR",
                        required=True)
    parser.add_argument("-o",
                        dest="outputDir",
                        help="Output directory.",
                        required=True)
    parser.add_argument("--keep-intermediates",
                        action='store_true',
                        default=False,
                        dest="keepIntermediates",
                        help="Keep intermediate files.",
                        required=False)
    parser.add_argument("--nCores",
                        default=multiprocessing.cpu_count(),
                        dest="nCores",
                        help="Total number of cores available.",
                        required=False,
                        type=int)
    return parser.parse_args()


class OCRWorkflow(WorkflowRunner):
    def __init__(self, jobs, keepIntermediates, lang, nCores):
        self.jobs = jobs
        self.keepIntermediates = keepIntermediates
        self.lang = lang
        self.nCores = nCores


    def workflow(self):
        ###
        # Task "mkdir_job": create output directories
        # Dependencies: None
        ###
        mkdir_jobs = []
        mkdir_job_number = 0
        for job in self.jobs:
            mkdir_job_number += 1
            cmd = 'mkdir -p "%s" "%s" "%s"' % (
                job["output_dir"],
                os.path.join(job["output_dir"], "tmp", "tesseract"),
                os.path.join(job["output_dir"], "tmp", "tiff_files")
            )
            mkdir_jobs.append(self.addTask(label="mkdir_job_-_%i" % (mkdir_job_number), command=cmd))

        ###
        # Task "split_job": split input file into one .tif file per page
        # Dependencies: mkdir_jobs
        ###
        split_jobs = []
        split_job_number = 0
        for job in self.jobs:
            split_job_number += 1
            cmd = 'pdftoppm "%s" "%s" -tiff -r 300 -tiffcompression lzw -cropbox' % (
                job["path"],
                os.path.join(job["output_dir"], "tmp", "tiff_files", "page")
            )
            split_jobs.append(self.addTask(label="split_job_-_%i" % (mkdir_job_number), command=cmd))

        ###
        # Task "tesseract_job": perform OCR
        # Dependencies: split_jobs
        ###
        self.waitForTasks()
        tesseract_jobs = []
        tesseract_job_number = 0
        for job in self.jobs:
            # This list is empty if you don't wait for split_jobs to complete
            for file in os.listdir(os.path.join(job["output_dir"], "tmp", "tiff_files")):
                tesseract_job_number += 1
                cmd = 'tesseract "%s" "%s" -l "%s" hocr pdf txt' % (
                    os.path.join(job["output_dir"], "tmp", "tiff_files", file),
                    os.path.join(job["output_dir"], "tmp", "tesseract", file.rsplit(".", 1)[0]),
                    self.lang
                )
                tesseract_jobs.append(self.addTask(label="tesseract_job_-_%i" % (tesseract_job_number), command=cmd, dependencies=split_jobs, nCores=min(4, self.nCores)))

        ###
        # Task "hocr_to_teip5_job": create TEI P5 file from hocr files
        # Dependencies: tesseract_jobs
        ###
        hocr_to_tei_jobs = []
        hocr_to_tei_job_number = 0
        for job in self.jobs:
            hocr_to_tei_job_number += 1
            cmd = 'hocrtotei "%s" "%s"' % (
                os.path.join(job["output_dir"], "tmp", "tesseract"),
                os.path.join(job["output_dir"], os.path.basename(job["path"]).rsplit(".", 1)[0] + ".xml")
            )
            hocr_to_tei_jobs.append(self.addTask(label="hocr_to_tei_job_-_%i" % (hocr_to_tei_job_number), command=cmd, dependencies=tesseract_jobs))

        ###
        # Task "pdf_merge_job": Merge .pdf files
        # Dependencies: tesseract_jobs
        ###
        pdf_merge_jobs = []
        pdf_merge_job_number = 0
        for job in self.jobs:
            pdf_merge_job_number += 1
            cmd = 'pdftk "%s"/*.pdf cat output "%s"' % (
                os.path.join(job["output_dir"], "tmp", "tesseract"),
                os.path.join(job["output_dir"], os.path.basename(job["path"]).rsplit(".", 1)[0] + ".pdf")
            )
            pdf_merge_jobs.append(self.addTask(label="pdf_merge_job_-_%i" % (pdf_merge_job_number), command=cmd, dependencies=tesseract_jobs))

        ###
        # Task "txt_merge_job": Merge .txt files
        # Dependencies: tesseract_jobs
        ###
        txt_merge_jobs = []
        txt_merge_job_number = 0
        for job in self.jobs:
            txt_merge_job_number += 1
            cmd = 'cat "%s"/*.txt > "%s"' % (
                os.path.join(job["output_dir"], "tmp", "tesseract"),
                os.path.join(job["output_dir"], os.path.basename(job["path"]).rsplit(".", 1)[0] + ".txt")
            )
            txt_merge_jobs.append(self.addTask(label="txt_merge_job_-_%i" % (txt_merge_job_number), command=cmd, dependencies=tesseract_jobs))

        ###
        # Task "cleanup_job": remove temporary files
        # Dependencies: hocr_to_tei_jobs + pdf_merge_jobs + txt_merge_jobs
        ###
        cleanup_jobs = []
        cleanup_job_counter = 0
        if not self.keepIntermediates:
            for job in self.jobs:
                cleanup_job_counter += 1
                cmd = 'rm -r "%s"' % (
                    os.path.join(job["output_dir"], "tmp")
                )
                cleanup_jobs.append(self.addTask(label="cleanup_job_-_%i" % (cleanup_job_counter), command=cmd, dependencies=hocr_to_tei_jobs + pdf_merge_jobs + txt_merge_jobs))

        ###
        # Task "zip_job": compress output
        # Dependencies: cleanup_jobs
        ###
        zip_jobs = []
        zip_job_number = 0
        for job in self.jobs:
            zip_job_number += 1
            cmd = 'zip -jqr %s %s' % (
                job["output_dir"] + "_-_ocr",
                job["output_dir"]
            )
            zip_jobs.append(self.addTask(label="zip_job_-_%i" % (zip_job_number), command=cmd, dependencies=cleanup_jobs))


def analyze_jobs(inputDir, outputDir, level=1):
    jobs = []

    if level > 2:
        return jobs

    for file in os.listdir(inputDir):
        if os.path.isdir(os.path.join(inputDir, file)):
            jobs += analyze_jobs(
                os.path.join(inputDir, file),
                os.path.join(outputDir, file),
                level + 1
            )
        elif file.endswith(".pdf"):
            jobs.append({"path": os.path.join(inputDir, file), "output_dir": os.path.join(outputDir, file.rsplit(".", 1)[0])})

    return jobs


def main():
    args = parse_arguments()

    wflow = OCRWorkflow(
        analyze_jobs(args.inputDir, args.outputDir),
        args.keepIntermediates,
        args.lang,
        args.nCores
    )

    retval = wflow.run(nCores=args.nCores)
    sys.exit(retval)


if __name__ == "__main__":
    main()