Convert pdfs to raster images6/22/2023 This does not have any influence on what I describe below. Older versions will only be able to extract images as PPM or PNM. There are only raster data, compressed with different methods. Within the PDF there is no such thing as PNG. ( Note: Only very recent versions of pdfimages, the Poppler version, will let your extract the images as PNG. dice-images-0001.png (a grayscale image).Here is a command to extract both images as PNG: pdfimages -png dice.pdf dice-images As you can see, there are two images list: one is an RGB raster image, the other is a grayscale raster image, dubbed as type smask (softmask). You should take a different approach and use a different tool to extract the image: use pdfimages (the tool used above with the -list parameter to display image properties from the PDF's pages). The results of this you've encountered when you tried to convert all white pixels into transparent ones: since the originally different objects are merged into one representation of pixels, you can no longer discriminate between them as required. (Of course you could crop only part of the page - but this gives you likewise the combination of all PDF objects from the cropped area.). The second, more fundamental problem however is: any image you get from converting a PDF page is the combination of all PDF objects overlayed on each other as they are from the page area. So this is the first problem when converting the PDF page: it does not give your the correct size of the contained images. Page num type width height color comp bpc enc interp object ID x-ppi y-ppi size ratioġ 0 image 800 600 rgb 3 8 image no 12 0 72 72 277K 20%ġ 1 smask 800 600 gray 1 8 image no 12 0 72 72 50.1K 11% This can be seen by running pdfimages -list: pdfimages -list dice.pdf However, the original size of the image embedded in the PDF page (612 x 792 pt) is 800 x 600 pixels. Hopefully, you can now convert your PDF pages to images in Linux using the Pdftoppm command-line tool.The command you used will convert the complete letter-sized PDF page (612 x 792 pt) into a PNG image. To see all the choices available and supported in pdftoppm, run the commands: $ pdftoppm -help $ pdftoppm -png -rx 300 -ry 300 Linux_For_Beginners.pdf Linux_For_Beginners In this example, we adjust the DP quality of Linux_For_Beginners.pdf to 300. To adjust, use the rx number which specifies the X resolution, and -ry the number which specifies the Y resolution, in DPI. Pdftoppm converts PDF pages to images with a DPI of 150 by default. To convert the first page only use the syntax below: $ pdftoppm -png -f 1 -l 1 Linux_For_Beginners.pdf Linux_For_Beginners The output will be images named Linux_For_Beginners-10.png, Linux_For_Beginners-11.png, etc. $ pdftoppm -png -f 10 -l 15 Linux_For_Beginners.pdf Linux_For_Beginners In the example below, we will convert pages 10 to 15 from Linux_For_Beginners.pdf to PNG. Where N specifies the first-page number to covert and -l N for the last page to convert. The syntax for specifying range is as follows: $ pdftoppm -f N -l N Convert PDF to Images in Linux Commandline 2. Each page of the PDF will be converted to PNG as Linux_For_Beginners-1.png, Linux_For_Beginners-2.png, etc.
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