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Oversampling + more than 1 img

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- Oversampling resolution can now be set from the cmd line (-o option)
- If a page contains more than one image, warn the user but process the
page anyway with a default resolution
This commit is contained in:
fritz-hh
2013-12-30 23:44:38 +01:00
parent 79ec1d994e
commit 95fe7cd3bc
3 changed files with 58 additions and 47 deletions
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src/ocrPage.sh
+25 -19
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@@ -19,8 +19,9 @@ KEEP_TMP="$7" # Keep the temporary files after processing (helpful for debugg
PREPROCESS_DESKEW="$8" # Deskew the page to be OCRed
PREPROCESS_CLEAN="$9" # Clean the page to be OCRed
PREPROCESS_CLEANTOPDF="${10}" # Put the cleaned paged in the OCRed PDF
PDF_NOIMG="${11}" # Request to generate also a PDF page containing only the OCRed text but no image (helpful for debugging)
TESS_CFG_FILES="${12}" # Specific configuration files to be used by Tesseract during OCRing
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
@@ -59,7 +60,7 @@ imageCharacteristics() {
pdfimages -f $page -l $page -j "$FILE_INPUT_PDF" "$curOrigImg" 1>&2
# count number of extracted images
nbImg=`ls -1 "$curOrigImg"* | wc -l`
[ $nbImg -ne "1" ] && echo "Page $page: Expecting exactly 1 image on page $page (found $nbImg). Exiting..." >&2 && return 1
[ $nbImg -ne "1" ] && echo "Page $page: Expecting exactly 1 image on page $page (found $nbImg). Page might not (only) contain a scanned image !!!" && return 1
# Get characteristics of the extracted image
curImg=`ls -1 "$curOrigImg"*`
propCurImg=`identify -format "%w %h %[colorspace]" "$curImg"`
@@ -124,19 +125,24 @@ curImgCharacteristics="$TMP_FLD/${page}-img-characteristics.txt" # Detected char
# auto-detect the characteristics of the embedded image
imageCharacteristics "$page" "$widthPDF" "$heightPDF" "$curImgCharacteristics"
case "$?" in
1) exit $EXIT_BAD_INPUT_FILE ;;
esac
# read the image characteristics
dpi=`cat "$curImgCharacteristics" | cut -f1 -d" "`
colorspaceCurImg=`cat "$curImgCharacteristics" | cut -f2 -d" "`
#in case the page contains more than one image, warn the user but go on with default parameters
if [ "$?" -eq "1" ]; then
dpi=300
echo "Page $page: Continuing anyway, assuming a default resolution of $dpi dpi"
colorspaceCurImg="sRGB"
else
# read the image characteristics from the file
dpi=`cat "$curImgCharacteristics" | cut -f1 -d" "`
colorspaceCurImg=`cat "$curImgCharacteristics" | cut -f2 -d" "`
fi
# perform oversampling if the resolution is not big enough
# to get good OCR results
[ $dpi -lt 250 ] && dpi=250 && [ $VERBOSITY -ge $LOG_WARN ] \
&& echo "Page $page: Low image resolution detected. Performing oversampling (at $dpi dpi) to try to get better OCR results. This will probably increase output file size."
if [ "$dpi" -lt "$OVERSAMPLING_DPI" ]; then
[ $VERBOSITY -ge $LOG_WARN ] && echo "Page $page: Low image resolution detected ($dpi dpi). Performing oversampling ($OVERSAMPLING_DPI dpi) to try to get better OCR results."
dpi="$OVERSAMPLING_DPI"
fi
# Identify if page image should be saved as ppm (color) or pgm (gray)
ext="ppm"
opt=""
@@ -151,7 +157,7 @@ curImgPixmapClean="$TMP_FLD/$page.cleaned.$ext"
# extract current page as image with right orientation and resolution
[ $VERBOSITY -ge $LOG_DEBUG ] && echo "Page $page: Extracting image as $ext file (${dpi} dpi)"
! pdftoppm -f $page -l $page -r $dpi $opt "$FILE_INPUT_PDF" > "$curImgPixmap" \
&& echo "Could not extract page $page as $ext from \"$FILE_INPUT_PDF\". Exiting..." >&2 && exit $EXIT_OTHER_ERROR
&& echo "Could not extract page $page as $ext from \"$FILE_INPUT_PDF\". Exiting..." && exit $EXIT_OTHER_ERROR
# if requested deskew image (without changing its size in pixel)
widthCurImg=$(($dpi*$widthPDF/72))
@@ -159,7 +165,7 @@ heightCurImg=$(($dpi*$heightPDF/72))
if [ "$PREPROCESS_DESKEW" -eq "1" ]; then
[ $VERBOSITY -ge $LOG_DEBUG ] && echo "Page $page: Deskewing image"
! convert "$curImgPixmap" -deskew 40% -gravity center -extent ${widthCurImg}x${heightCurImg} "$curImgPixmapDeskewed" \
&& echo "Could not deskew \"$curImgPixmap\". Exiting..." >&2 && exit $EXIT_OTHER_ERROR
&& echo "Could not deskew \"$curImgPixmap\". Exiting..." && exit $EXIT_OTHER_ERROR
else
cp "$curImgPixmap" "$curImgPixmapDeskewed"
fi
@@ -170,7 +176,7 @@ if [ "$PREPROCESS_CLEAN" -eq "1" ]; then
! unpaper --dpi $dpi --mask-scan-size 100 \
--no-deskew --no-grayfilter --no-blackfilter --no-mask-center --no-border-align \
"$curImgPixmapDeskewed" "$curImgPixmapClean" 1> /dev/null \
&& echo "Could not clean \"$curImgPixmapDeskewed\". Exiting..." >&2 && exit $EXIT_OTHER_ERROR
&& echo "Could not clean \"$curImgPixmapDeskewed\". Exiting..." && exit $EXIT_OTHER_ERROR
else
cp "$curImgPixmapDeskewed" "$curImgPixmapClean"
fi
@@ -178,7 +184,7 @@ fi
# perform OCR
[ $VERBOSITY -ge $LOG_DEBUG ] && echo "Page $page: Performing OCR"
! tesseract -l "$LAN" "$curImgPixmapClean" "$curHocr" hocr $TESS_CFG_FILES 1> /dev/null 2> /dev/null \
&& echo "Could not OCR file \"$curImgPixmapClean\". Exiting..." >&2 && exit $EXIT_OTHER_ERROR
&& echo "Could not OCR file \"$curImgPixmapClean\". Exiting..." && exit $EXIT_OTHER_ERROR
mv "$curHocr.html" "$curHocr"
# embed text and image to new pdf file
@@ -189,13 +195,13 @@ else
fi
[ $VERBOSITY -ge $LOG_DEBUG ] && echo "Page $page: Embedding text in PDF"
! python2 $SRC/hocrTransform.py -r $dpi -i "$image4finalPDF" "$curHocr" "$curOCRedPDF" \
&& echo "Could not create PDF file from \"$curHocr\". Exiting..." >&2 && exit $EXIT_OTHER_ERROR
&& echo "Could not create PDF file from \"$curHocr\". Exiting..." && exit $EXIT_OTHER_ERROR
# if requested generate special debug PDF page with visible OCR text
if [ $PDF_NOIMG -eq "1" ] ; then
[ $VERBOSITY -ge $LOG_DEBUG ] && echo "Page $page: Embedding text in PDF (debug page)"
! python2 $SRC/hocrTransform.py -b -r $dpi "$curHocr" "$curOCRedPDFDebug" \
&& echo "Could not create PDF file from \"$curHocr\". Exiting..." >&2 && exit $EXIT_OTHER_ERROR
&& echo "Could not create PDF file from \"$curHocr\". Exiting..." && exit $EXIT_OTHER_ERROR
fi
# delete temporary files created for the current page