ImageMagick: resize and ignore aspect ratio

for f in *.jpg; do echo $f; mogrify -resize 64x64\! -set colorspace Gray -separate -average $f; done

ImageMagick: montage images into one

montage -label '%f' -geometry +4+4 -pointsize 20 -tile 4x6 *.tiff mtg.jpg

ImageMagick: Flatten image results in white image

Instead of -flatten option try using -layers trim-bounds

ImageMagick: remove alpha channel from tiff images

mogrify -flatten -alpha off *.tiff

Imagemagick: bash split large images into smaller

for f in *.tiff ; do fbase=`echo $f | cut -d '.' -f 1`; echo $fbase; convert -crop 510x510 +repage $f sub/${fbase}_%02d.tiff ; done

Imagemagick: Conver multiple pdf into image so that all pages are in one file for each pdf

mogrify -append -format png -density 200 -alpha remove *.pdf

Compile ImageMagick 7 on Ubuntu 16.04

ImageMagick: Crop images in half verticly

Left halfmogrify -gravity West -crop 50%x100%+0+0 *.tiff Right halfmogrify -gravity East -crop 50%x100%+0+0 *.tiff

ImageMagick: remove alpha and flatten

mogrify -flatten -type Grayscale -alpha remove *.tiff

Ubuntu: pdf to images and images to pdf

pdftoppm -png a_pdf_file.pdf img
convert *.png a_pdf_file_as_img.pdf

ImageMagick: resize images to specific width or hight

For example to resize tif images to width of 512 pixels:mogrify -resize 512 *.tif
Whereas to resize tif images to height of 512 pixels:mogrify -resize x512 *.tif

Imagemagick: Flattening tiff images

mogrify -alpha off -colorspace gray -depth 8 -flatten *.tiff

Reading DICOM files in Python 3

In Python 3, dicom files can be read, analysied and processed using Wand which is Python binding for ImageMagic. The example below shows how to get medical and image date embedded in DICOM and also how to disply the image itself.

ImageMagick: get size and resolution (DPI) of images

To get size and resolution in DPI of many images at once using ImageMagick, we can use this command:identify -format "%w x %h %x x %y\n" *.tiff This result for example in:576 x 432 72 PixelsPerInch x 72 PixelsPerInch 576 x 432 72 PixelsPerInch x 72 PixelsPerInch 576 x 432 72 PixelsPerInch x 72 PixelsPerInch 576 x 432 72 PixelsPerInch x 72 PixelsPerInch 576 x 432 72 PixelsPerInch x 72 PixelsPerInch 576 x 432 72 PixelsPerInch x 72 PixelsPerInch

ImageMagick: batch resize and DPI change

mogrify -resize 59.06% -density 150x150 *.tif
mogrify -resize 1024x1234 -density 150x150 *.tif
If the images are in grayscale than the above will convert them to RGB. Thus one can use the following: mogrify -resize 59.06% -density 150x150 -colorspace gray -layers flatten *.tif
mogrify -resize 1024x1234 -density 150x150 -colorspace gray -layers flatten *.tif


ImageMagick: Make thumbs of images

For example to make jpg thumbs of all tiff images in a current director one can use:for f in *.tiff; do bname=`basename $f .tiff` ; convert -resize 256x256 $f ./thumbs/$bname.jpg; done

ImageMagick: Flatten and convert an image to grayscale

In short, to flatten and convert to grayscale all images in current director one can use: mogrify -flatten -type Grayscale *or mogrify -flatten -alpha remove *.tiff

imagemagick: crop all images

Example:convert rose: -crop 40x30+10+10 +repage repage.gif

ImageMagick: split one image to smaller images

Lets assume that we have a 1024x1024 pixel image called test.tif and that we want to split this image into 64x64 non-overlapping images called test001.tif, test002.tif, test003.tiff,....
We can do this using this command from
convert -crop 64x64 +repage test.tif test%02d.tif

How ImageMagick can save you time

ImageMagick is a great tool! Many times it has saved me from programming. Here is just one example of many applications of the ImageMagick that can save one's time.

Recently, I was asked to check whether a set of images (few hundreds of them) contains one particular image. So, basically I was given and image (called testImage.tiff), and I needed to check whether this image belongs to a set a few hundreds of images. En example of the images from the set is below:

So how to anwser this? You can do manual (i.e. visual comparison), you can also write some simple script in Python with PIL. All would take some time. But why to do this, if you can just write one for loop in bash with compare command from ImageMagick?

So first thing I did is to create the following folders:

The input folder contains all images from the set, the output folder will be where the results of my search will be stored, and the testImage.tiff is my test image.

So thanks to ImageMagick's, the only thing I had to do is to execute its compare command on all images from the set (i.e. input folder).  In other words, I compared, in a loop, an image from the set with the testImage.tiff and the results of the comparison went to output folder. Below is the bash for loop that was executed inside the input folder.

for f in *.tiff ; do
compare $f ../testImage.tiff ../output/$f ;
doneAfter loop finished, I could go to output folder, and quickly find out whether testImage.tiff is in the set:

As can be seen in the above picture, the testImage.tiff belongs this this set.

One limitation of this procedure is that I had to manually go through the output folder. But because all not matching images are in red, it was very quick to find, the one image that was not red. (if any). Additionally, if the testImage.tiff and images from the set were of different size or type additional code would be necessary.

So thanks to the ImageMagick, I could do the job in just a few minutes.