Legacy ImageMagick Discussions Archive

Dear forum users, please help me to improve my script speed, get the paper white and chars black ready for use in e-books.

My current script is:

convert $i.jpg -matte -background none -virtual-pixel background
-distort Perspective "0,0 0,0 1998,0 1990,0 2003,1335 1998,1335 35,1325 0,1325" -trim -rotate -90 -quality 10 -sharpen 0x1.0 $i.pdf

I use the code to convert photos taken with two Canon 400D cameras on my book scanner robot at a speed of 2 scans per second (7200 scans per hour)

original photo from a camera exp. 1/80:
http://www.bookscanner.si/Anthony/capture000597.jpg
original photo from a camera exp. 1/60:
http://www.bookscanner.si/Anthony/capture000605.jpg
img size: 3189 x 2126 300 dpi

1/80 converted to a pdf: http://www.bookscanner.si/Anthony/3.pdf
1/60 converted to a pdf: http://www.bookscanner.si/Anthony/19.pdf

As you can see I have a couple of other problems:
some of the text shows through the page of the book.
There are some compression artefacts the pdf.

Should the photos be resized for the e-book pdf format before conversion?
Can I combine the perspective distort and rotate in a different distort command to improve the speed?

Thank you.

You may be seeing jpg compression artifacts in your output. Have tried scanning either directly to pdf or to png or tiff to avoid the jpg compression issues?

The OP is using a canon dslr and the formats are either jpg or RAW.

Looking at the specifications for that camera " Continuous: 3.0 fps up to 27 JPEG / 10 RAW frames ". I would guess at the speed he is working RAW would fill the buffer after 10 photos.

If you don't like the compression artefacts, don't use such a low quality number.