143 lines
6.4 KiB
Bash
143 lines
6.4 KiB
Bash
#!/bin/sh
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##############################################################################
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# Copyright (c) 2013: fritz-hh from Github (https://github.com/fritz-hh)
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##############################################################################
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. "./src/config.sh"
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# Initialization of variables passed by args
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FILE_INPUT_PDF="$1"
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PAGE_INFO="$2"
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NUM_PAGES="$3"
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TMP_FLD="$4"
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VERBOSITY="$5"
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LAN="$6"
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KEEP_TMP="$7"
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PREPROCESS_DESKEW="$8"
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PREPROCESS_CLEAN="$9"
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PREPROCESS_CLEANTOPDF="${10}"
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PDF_NOIMG="${11}"
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TESS_CFG_FILES="${12}"
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page=`echo $PAGE_INFO | cut -f1 -d" "`
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[ $VERBOSITY -ge $LOG_INFO ] && echo "Processing page $page / $NUM_PAGES"
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# create the name of the required file
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curOrigImg="$TMP_FLD/${page}_Image" # original image available in the current PDF page
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# (the image file may have a different orientation than in the pdf file)
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curHocr="$TMP_FLD/$page.hocr" # hocr file to be generated by the OCR SW for the current page
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curOCRedPDF="$TMP_FLD/${page}-ocred.pdf" # PDF file containing the image + the OCRed text for the current page
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curOCRedPDFDebug="$TMP_FLD/${page}-debug-ocred.pdf" # PDF file containing data required to find out if OCR worked correctly
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# get width / height of PDF page (in pt)
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widthPDF=`echo $PAGE_INFO | cut -f2 -d" "`
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heightPDF=`echo $PAGE_INFO | cut -f3 -d" "`
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[ $VERBOSITY -ge $LOG_DEBUG ] && echo "Page $page: size ${heightPDF}x${widthPDF} (h*w in pt)"
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# extract raw image from pdf file to compute resolution
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# unfortunately this image can have another orientation than in the pdf...
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# so we will have to extract it again later using pdftoppm
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pdfimages -f $page -l $page -j "$FILE_INPUT_PDF" "$curOrigImg" 1>&2
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# count number of extracted images
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nbImg=`ls -1 "$curOrigImg"* | wc -l`
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[ $nbImg -ne "1" ] && echo "Expecting exactly 1 image on page $page (found $nbImg). Exiting..." >&2 && exit $EXIT_BAD_INPUT_FILE
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# Get characteristics of the extracted image
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curImg=`ls -1 "$curOrigImg"*`
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propCurImg=`identify -format "%w %h %[colorspace]" "$curImg"`
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widthCurImg=`echo "$propCurImg" | cut -f1 -d" "`
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heightCurImg=`echo "$propCurImg" | cut -f2 -d" "`
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colorspaceCurImg=`echo "$propCurImg" | cut -f3 -d" "`
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# switch height/width values if the image has not the right orientation
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# we make here the assumption that vertical/horizontal dpi are equal
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# we will check that later
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if [ $((($heightPDF-$widthPDF)*($heightCurImg-$widthCurImg))) -lt 0 ]; then
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[ $VERBOSITY -ge $LOG_DEBUG ] && echo "Page $page: Extracted image has wrong orientation. Inverting image height/width values"
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tmpval=$heightCurImg
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heightCurImg=$widthCurImg
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widthCurImg=$tmpval
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fi
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[ $VERBOSITY -ge $LOG_DEBUG ] && echo "Page $page: size ${heightCurImg}x${widthCurImg} (h*w pixel)"
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# compute the resolution of the image
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dpi_x=`echo "scale=5;$widthCurImg*72/$widthPDF" | bc`
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dpi_y=`echo "scale=5;$heightCurImg*72/$heightPDF" | bc`
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# compute the maximum allowed resolution difference that can be cause by:
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# - the truncated PDF with/height in pt
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# - the precision of dpi value
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epsilon=`echo "scale=5;($widthCurImg*72/$widthPDF^2)+($heightCurImg*72/$heightPDF^2)+0.00002" | bc` # max inaccuracy due to truncation of PDF size in pt
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[ `echo "($dpi_x - $dpi_y) < $epsilon " | bc` -eq 0 -o `echo "($dpi_y - $dpi_x) < $epsilon " | bc` -eq 0 ] \
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&& echo "Resolutions difference ($dpi_x/$dpi_y) higher than expected ($epsilon). Exiting..." >&2 && exit $EXIT_BAD_INPUT_FILE
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dpi=`echo "scale=5;($dpi_x+$dpi_y)/2+0.5" | bc` # adding 0.5 is required for rounding
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dpi=`echo "scale=0;$dpi/1" | bc` # round to the nearest integer
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# Identify if page image should be saved as ppm (color) or pgm (gray)
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ext="ppm"
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opt=""
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if [ "$colorspaceCurImg" = "Gray" ]; then
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ext="pgm"
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opt="-gray"
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fi
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curImgPixmap="$TMP_FLD/$page.$ext"
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curImgPixmapDeskewed="$TMP_FLD/$page.deskewed.$ext"
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curImgPixmapClean="$TMP_FLD/$page.cleaned.$ext"
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# extract current page as image with right orientation and resoltution
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[ $VERBOSITY -ge $LOG_DEBUG ] && echo "Page $page: Extracting image as $ext file (${dpi} dpi)"
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! pdftoppm -f $page -l $page -r $dpi $opt "$FILE_INPUT_PDF" > "$curImgPixmap" \
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&& echo "Could not extract page $page as $ext from \"$FILE_INPUT_PDF\". Exiting..." >&2 && exit $EXIT_OTHER_ERROR
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# if requested deskew image (without changing its size in pixel)
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if [ "$PREPROCESS_DESKEW" -eq "1" ]; then
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[ $VERBOSITY -ge $LOG_DEBUG ] && echo "Page $page: Deskewing image"
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! convert "$curImgPixmap" -deskew 40% -gravity center -extent ${widthCurImg}x${heightCurImg} "$curImgPixmapDeskewed" \
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&& echo "Could not deskew \"$curImgPixmap\". Exiting..." >&2 && exit $EXIT_OTHER_ERROR
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else
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cp "$curImgPixmap" "$curImgPixmapDeskewed"
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fi
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# if requested clean image with unpaper to get better OCR results
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if [ "$PREPROCESS_CLEAN" -eq "1" ]; then
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[ $VERBOSITY -ge $LOG_DEBUG ] && echo "Page $page: Cleaning image with unpaper"
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! unpaper --dpi $dpi --mask-scan-size 100 \
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--no-deskew --no-grayfilter --no-blackfilter --no-mask-center --no-border-align \
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"$curImgPixmapDeskewed" "$curImgPixmapClean" 1> /dev/null \
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&& echo "Could not clean \"$curImgPixmapDeskewed\". Exiting..." >&2 && exit $EXIT_OTHER_ERROR
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else
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cp "$curImgPixmapDeskewed" "$curImgPixmapClean"
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fi
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# perform OCR
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[ $VERBOSITY -ge $LOG_DEBUG ] && echo "Page $page: Performing OCR"
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! tesseract -l "$LAN" "$curImgPixmapClean" "$curHocr" hocr $TESS_CFG_FILES 1> /dev/null 2> /dev/null \
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&& echo "Could not OCR file \"$curImgPixmapClean\". Exiting..." >&2 && exit $EXIT_OTHER_ERROR
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mv "$curHocr.html" "$curHocr"
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# embed text and image to new pdf file
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if [ "$PREPROCESS_CLEANTOPDF" -eq "1" ]; then
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image4finalPDF="$curImgPixmapClean"
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else
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image4finalPDF="$curImgPixmapDeskewed"
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fi
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[ $VERBOSITY -ge $LOG_DEBUG ] && echo "Page $page: Embedding text in PDF"
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! python2 $SRC/hocrTransform.py -r $dpi -i "$image4finalPDF" "$curHocr" "$curOCRedPDF" \
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&& echo "Could not create PDF file from \"$curHocr\". Exiting..." >&2 && exit $EXIT_OTHER_ERROR
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# if requested generate special debug PDF page with visible OCR text
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if [ $PDF_NOIMG -eq "1" ] ; then
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[ $VERBOSITY -ge $LOG_DEBUG ] && echo "Page $page: Embedding text in PDF (debug page)"
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! python2 $SRC/hocrTransform.py -b -r $dpi "$curHocr" "$curOCRedPDFDebug" \
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&& echo "Could not create PDF file from \"$curHocr\". Exiting..." >&2 && exit $EXIT_OTHER_ERROR
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fi
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# delete temporary files created for the current page
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# to avoid using to much disk space in case of PDF files having many pages
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if [ $KEEP_TMP -eq 0 ]; then
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rm "$curOrigImg"*.*
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rm "$curHocr"
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rm "$curImgPixmap"
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rm "$curImgPixmapDeskewed"
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rm "$curImgPixmapClean"
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fi
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exit 0 |