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Add command line option to skip pages that contain font data

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If a page contains font data, the script would abort, unless -f was given,
in which case it would use pdftoppm to rasterize the font into a bitmap
and then attempt to OCR it. -f is almost certainly not what users want
unless they want to debug OCR or something.

If a PDF already has fonts it either was OCR'd already, or it is
a composite file containing, for example, some scanned documents appended
to a text report.  In the latter case, this -s option provides OCR on
pages that don't have it without changing those that do, and if a PDF
was completely OCRed it will be converted to PDF/A.  In batch jobs with
a mix of OCR and non-OCR the implicit conversion to PDF/A is also useful.
This commit is contained in:
Jim Barlow
2014-09-25 02:43:40 -07:00
parent d510e7e4ae
commit 09bbe92611
2 changed files with 20 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files
OCRmyPDF.sh
+13 -2
View File
@@ -41,6 +41,7 @@ Usage: OCRmyPDF.sh [-h] [-v] [-g] [-k] [-d] [-c] [-i] [-o dpi] [-f] [-l languag
(default: no oversampling performed)
-f : Force to OCR the whole document, even if some page already contain font data
(which should not be the case for PDF files built from scanned images)
-s : If pages contain font data, do not perform processing on that page, but include the page in the final output.
-l : Set the language of the PDF file in order to improve OCR results (default "eng")
Any language supported by tesseract is supported (Tesseract uses 3-character ISO 639-2 language codes)
Multiple languages may be specified, separated by '+' characters.
@@ -82,10 +83,11 @@ PREPROCESS_CLEANTOPDF="0" # 0=no, 1=yes (put cleaned image in final PDF)
OVERSAMPLING_DPI="0" # 0=do not perform oversampling (dpi value under which oversampling should be performed)
PDF_NOIMG="0" # 0=no, 1=yes (generates each PDF page twice, with and without image)
FORCE_OCR="0" # 0=do not force, 1=force (force to OCR the whole document, even if some page already contain font data)
SKIP_TEXT="0" # 0=do not skip text pages, 1=skip text pages
TESS_CFG_FILES="" # list of additional configuration files to be used by tesseract
# Parse optional command line arguments
while getopts ":hvgkdcio:fl:C:" opt; do
while getopts ":hvgkdcio:fsl:C:" opt; do
case $opt in
h) usage ; exit 0 ;;
v) VERBOSITY=$(($VERBOSITY+1)) ;;
@@ -96,6 +98,7 @@ while getopts ":hvgkdcio:fl:C:" opt; do
i) PREPROCESS_CLEANTOPDF="1" ;;
o) OVERSAMPLING_DPI="$OPTARG" ;;
f) FORCE_OCR="1" ;;
s) SKIP_TEXT="1" ;;
l) LAN="$OPTARG" ;;
C) TESS_CFG_FILES="$OPTARG $TESS_CFG_FILES" ;;
\?)
@@ -119,6 +122,12 @@ if [ "$#" -ne "2" ]; then
exit $EXIT_BAD_ARGS
fi
if [ "$SKIP_TEXT" -eq "1" -a "$FORCE_OCR" -eq "1" ]; then
echo "Options -f and -s are mutually exclusive; choose one or the other"
usage
exit $EXIT_BAD_ARGS
fi
! absolutePath "$1" > /dev/null \
&& echo "The folder in which the input file should be located does not exist. Exiting..." && exit $EXIT_BAD_ARGS
FILE_INPUT_PDF="`absolutePath "$1"`"
@@ -141,6 +150,7 @@ cd "$BASEPATH"
! command -v pdfimages > /dev/null && echo "Please install poppler-utils. Exiting..." && exit $EXIT_MISSING_DEPENDENCY
! command -v pdftoppm > /dev/null && echo "Please install poppler-utils. Exiting..." && exit $EXIT_MISSING_DEPENDENCY
! command -v pdffonts > /dev/null && echo "Please install poppler-utils. Exiting..." && exit $EXIT_MISSING_DEPENDENCY
! command -v pdfseparate > /dev/null && echo "Please install or update poppler-utils to at least 0.24.5. Exiting..." && exit $EXIT_MISSING_DEPENDENCY
[ $PREPROCESS_CLEAN -eq 1 ] && ! command -v unpaper > /dev/null && echo "Please install unpaper. Exiting..." && exit $EXIT_MISSING_DEPENDENCY
! command -v tesseract > /dev/null && echo "Please install tesseract and tesseract-data. Exiting..." && exit $EXIT_MISSING_DEPENDENCY
! command -v python2 > /dev/null && echo "Please install python v2.x. Exiting..." && exit $EXIT_MISSING_DEPENDENCY
@@ -186,6 +196,7 @@ if [ $VERBOSITY -ge $LOG_DEBUG ]; then
pdfimages -v
pdftoppm -v
pdffonts -v
pdfseparate -v
echo "--------------------------------"
echo "unpaper version:"
unpaper --version
@@ -254,7 +265,7 @@ numpages=`tail -n 1 "$FILE_PAGES_INFO" | cut -f1 -d" "`
# process each page of the input pdf file
parallel --gnu -q -k --halt-on-error 1 "$OCR_PAGE" "$FILE_INPUT_PDF" "{}" "$numpages" "$TMP_FLD" \
"$VERBOSITY" "$LAN" "$KEEP_TMP" "$PREPROCESS_DESKEW" "$PREPROCESS_CLEAN" "$PREPROCESS_CLEANTOPDF" "$OVERSAMPLING_DPI" \
"$PDF_NOIMG" "$TESS_CFG_FILES" "$FORCE_OCR" < "$FILE_PAGES_INFO"
"$PDF_NOIMG" "$TESS_CFG_FILES" "$FORCE_OCR" "$SKIP_TEXT" < "$FILE_PAGES_INFO"
ret_code="$?"
[ $ret_code -ne 0 ] && exit $ret_code
src/ocrPage.sh
+7 -2
View File
@@ -23,6 +23,7 @@ OVERSAMPLING_DPI="${11}" # Oversampling resolution in dpi
PDF_NOIMG="${12}" # Request to generate also a PDF page containing only the OCRed text but no image (helpful for debugging)
TESS_CFG_FILES="${13}" # Specific configuration files to be used by Tesseract during OCRing
FORCE_OCR="${14}" # Force to OCR, even if the page already contains fonts
SKIP_TEXT="${15}" # Skip OCR on pages that contain fonts and include the page anyway
@@ -119,8 +120,12 @@ dpi=$DEFAULT_DPI # default resolution
getImgInfo "$page" "$widthPDF" "$heightPDF" "$curImgInfo"
ret_code="$?"
# in case the page contains text do not OCR, unless the FORCE_OCR flag is set
if ([ "$ret_code" -eq "1" ] && [ "$FORCE_OCR" -eq "0" ]); then
# Handle pages that already contain a text layer
if ([ "$ret_code" -eq "1" ] && [ "$SKIP_TEXT" -eq "1" ]); then
echo "Page $page: Skipping processing because page contains text..."
pdfseparate -f $page -l $page ${FILE_INPUT_PDF} $curOCRedPDF
exit 0
elif ([ "$ret_code" -eq "1" ] && [ "$FORCE_OCR" -eq "0" ]); then
echo "Page $page: Exiting... (Use the -f option to force OCRing, even though fonts are available in the input file)" && exit $EXIT_BAD_INPUT_FILE
elif ([ "$ret_code" -eq "1" ] && [ "$FORCE_OCR" -eq "1" ]); then
[ $VERBOSITY -ge $LOG_WARN ] && echo "Page $page: OCRing anyway, assuming a default resolution of $dpi dpi"