OCRmyPDF.sh: prepare intelligent image extraction

preparation of extraction of the image in the same resolution than the
original image inside the pdf file

OCRmyPDF.sh

@@ -20,8 +20,23 @@ page="1"
 while [ $page -le $numpages ]; do
 
 	# extract image from current pdf page
-	echo "Page $page: Extracting image from PDF"
 	pdftk "$infile" cat $page output "${tmp}/${page}.pdf" > /dev/null
+
+	# get the size of the pdf (width / height) page in pt (inch*72)
+	# identify -format "return %w, %h\n" "${tmp}/${page}.pdf"
+	
+	# extract image from pdf file (keeping the resolution as available in the pdf file)
+	# pdfimages -f 1 -l 1 "${tmp}/${page}.pdf" ${page} 1>&2
+
+	# itterate the extracted images (there can be more than 1 image on the page)
+	# and get there respective number of x/y pixel 
+	# identify -format "return %w, %h\n" img1-xxx.ppm
+	
+	# compute the resolution of the whole page (taking into account all images)
+	
+	
+	# extract the image with the right resolution
+	echo "Page $page: Extracting image from PDF"	
 	pdftoppm -r $dpi "${tmp}/${page}.pdf" > "${tmp}/${page}.ppm"
 
 	# improve quality of the image to get better ocr results
@@ -35,9 +50,13 @@ while [ $page -le $numpages ]; do
 	tesseract -l ${lan} "${tmp}/${page}.forocr.ppm" "${tmp}/${page}.hocr" hocr 1> /dev/null 2> /dev/null 
 	cp "${tmp}/${page}.hocr.html" "${tmp}/${page}.hocr"
 
+	# compress image to be put inside the pdf file
+	echo "Page $page: Compress image for final PDF file"
+	convert "${tmp}/${page}.forocr.ppm" "${tmp}/${page}.forpdf.jpg"
+	
 	# embed text and image to new pdf file
 	echo "Page $page: Embedding text in PDF"
-	python hocrTransform.py -r 300 -i "${tmp}/${page}.forocr.ppm" "${tmp}/${page}.hocr" "${tmp}/${page}-ocred.pdf"
+	python hocrTransform.py -r $dpi -i "${tmp}/${page}.forpdf.jpg" "${tmp}/${page}.hocr" "${tmp}/${page}-ocred.pdf"
 	
 	# go to next page of the pdf
 	page=$(($page+1))
@@ -48,6 +67,7 @@ done
 pdftk ${tmp}/*-ocred.pdf cat output "${tmp}/ocred.pdf"
 
 # insert metadata
+# TODO
 
 # validate generated pdf file (compliance to PDF/A) 
 #java -jar jhove/bin/JhoveApp.jar -m PDF-hul "$1" |egrep "Status|Message"