I test this on my windows machine, but in the end it should run here:
identify -version
Version: ImageMagick 6.8.9-9 Q16 x86_64 2018-09-28 http://www.imagemagick.org
I have a long tiff (1700x96274) and I split it into multiple tiff pages with this command:
magick convert large.tiff -crop 1700x2300 -page A4 cropped_%d.tiff
But then I'm cutting text or images very often. What I want is a smart border with mostly white, e.g. between 2200-2400.
How can cut the image into multiple images with detecting white (mostly) spaces and use them as variable border?
Related
I am seeing the following image in a paper:
However, when I download the associated dataset with the paper, the images are like this:
How can I make the almost black images in the dataset looking like the one in the paper?
link to dataset: http://www.cs.bu.edu/~betke/research/HRMF2/
link to paper: http://people.bu.edu/breslav/084.pdf
The contents of this dataset is saved as 16 png data. But ordinary display has only 8bit dynamic range. So we cannot display them without windowing. Please try to use ImageJ, it can map 16bit data into visible 8bit data.
https://imagej.nih.gov/ij/index.html
It can show as following.
As the other answers rightly say, the images are in 16-bit PNG format. You can convert one to a conventionally scaled, viewable JPEG with ImageMagick which is installed on most Linux distros and is available for macOS and Windows.
So, in Terminal:
magick 183.png -auto-level 183.jpg
If you would like to convert all 800 images to JPEGs in one go, you can use ImageMagick's mogrify like this:
magick mogrify -format JPEG -auto-level *png
Note that if your ImageMagick is the older v6 (as opposed to the v7 commands I used) the two commands become:
convert 183.png -auto-level 183.jpg
mogrify -format JPEG -auto-level *png
The images in this dataset have high dynamic range of 16-bits per pixel. Image viewer you are using is mapping 16-bit pixels to 8-bit ones, in order to display them (most displays can only effectively handle 8 or 10 bits of brightness). Most image viewers will just truncate the least significant 8 bits, which in your case produces nearly black image. To get better results, use ImageJ (Fiji distribution is the easiest way to get started), which displays this:
I am looking to batch resize pictures to a specific pixel size while maintaining the aspect ratio. Is their a way that the picture aspect can be preserved and the rest of the space can be filled in with white? For example, I resize an image to 200 x 200 and due to preserving the aspect ratio it is changed to 200 x 194. I would like the actual image to remain 200 x 194 and white space to fill in the remaining area to create an image that is 200 x 200 px. Thank you in advance!
You can do that with ImageMagick which is included in most Linux distros and is available for macOS and Windows.
Just in Terminal, or Command Prompt on Windows:
magick input.jpg -background white -resize 200x200 -gravity center -extent 200x200 result.jpg
If you have many files to do, you may be better using ImageMagick's mogrify command, which will do them all in one go for you! So make a new directory called processed for the output files and then use this to process all PNG files in the current directory:
magick mogrify -path processed -background white -resize 200x200 -gravity center -extent 200x200 '*.png'
I don't know if you are on Windows or not, so you may or may not need the single quotes around the filenames at the end of that command. Basically, it determines whether the expansion of the filename list is done by the shell (which has limitations on the number of files), or internally by ImageMagick (which does not).
If you are running anything older than v7, the commands become:
convert input.jpg ...
or
mogrify ...
I'm looking for a database with a lot of high-resolution CIE Lab* images. Do you know where can I find it? I found RGB images only.
There are not many formats that are able to store images in CIE Lab colourspace, in fact the only one I know of is TIF and I believe CIE Lab colourspace is actually only an extension that not all software is able to handle.
I can only suggest you find a suitable database in another format and convert it yourself. You can do that painlessly with ImageMagick which is included in most Linux distros and is available for macOS and Windows. So, to convert a single hi-res PNG file to CIE Lab colourspace and save as TIF, you could run this in Terminal:
magick input.png -colorspace Lab result.tif
If you had hundreds of PNGs, you could do them all in one go with:
magick mogrify -colorspace Lab -format TIF *png
If you are using ImageMagick v6 or older, use:
convert input.png -colorspace Lab result.tif # for single image
mogrify -colorspace Lab -format TIF *png # for multiple images
I have a ps image that I want to convert to a gif image with horizontal by vertical dimensions of 900 and 800 respectively. I have tried to use the command:
convert panel.gs -resize x800 y900 panel.gif
or also:
convert panel.gs -resize 900x800 panel.gif
Can you help me to tweak the convert commands so I can get the desired results?
.gs is not a valid suffix. Did you mean .ps?
Imagemagick will need ghostscript as a delegate. You did not say what was wrong nor what platform or what version of Imagemagick.
If the image does not have the same aspect ratio as the final dimensions you want, you will either 1) need to distort it to fit using !, 2) resize it and then extend to the size you want filling with background color, or 3) resize it with ^ and crop it to the size you want.
convert panel.ps -resize "900x800!" panel.gif
convert panel.ps -resize 900x800 -gravity center -background white -extent 900x800 panel.gif
convert panel.ps -resize "900x800^" -gravity center -extent 900x800 panel.gif
Well, firstly you haven't actually said what's wrong with the two commands that you have tried already.....
Your PostScript program probably does not contain an 'image' as such, PostScript is not a bitmap format its a programming language.
You can use Ghostscript to render the PostScript to an image, and then use ImageMagick to resize that image, possibly you can combine these two steps, or just perform a single conversion, it depends on what exactly you want to happen, which isn't clear.
If (for example) your PostScript program requests a media size of 9 inches by 8 then you can create a bitmap image by simply setting the resolution to 100 dpi using -r100.
If you want the image scaled differently in each direction, then you need to set a non-square resolution. For example if the PostScript program requests media of 9 inches by 4 then you need to set the resolution to 100x200 in order to get an image exactly 900 x 800 pixels. You would use -r100x200 for this.
The alternative, from a PostScript point of view, is to set the media size to a given
value in pixels (using -g900x800) and set -dDFIXEDMEDIA which prevents the PostScript program from changing it. You can then use -dFitPage which will have Ghostscript scale the content to fit the page. However it will scale the content equally in both directions, which may leave white space around the edge.
Now since Ghostscritp doesn't write GIF directly you'll need to load whatever bitmap format you select into IM in order to write it out as a GIF, so perhaps the simplest solution is just to use Ghostscript to render the PostScript to a defined resolution (eg 100 dpi) and then load that image into IM and rescale it there.
Since IM (and therefore convert) use Ghostscript to process PostScript programs, that's what's happening now so it isn't obvious to me what your problem is.
I have two questions:
Firstly, how to detect the area of bar code target in an image (like the sample images), which may have a few noises.
Secondly, how to efficiently do the detection, for instance, in 1/30 seconds.
Squash (resize) the image till it is only 1 pixel tall, then normalise it to the full range of 0-255 and threshold. I am using ImageMagick at the command-line here - it is installed on most Linux distros and is available for OSX and Windows also with Python, PHP, Ruby, C/C++ bindings.
convert barcode.png -resize x1! -scale x10! -normalize -threshold 50% result.png
I have then scaled it to 10 pixels tall so you can actually see it on here - but you would keep the original width and have a height of one pixel. Then just find the first white pixel in your single row of pixels.
Your recently added, smaller barcode gives this: