Crop based on aspect ratio - command-line

I have been using this command to crop "portrait" aspect ratio photos.
magick in*.png -resize x1080 -gravity center -extent 640 out.png
I would like to use a similar command on a mixed group of photos, such that
"portrait" photos are cropped to 640x1080
"landscape" photos are cropped to 1280x1080
Is this possible with a "one liner"?

Using IMv7
-extent '%[fx: w>h ? 1280 : 640]'
Crop with specific aspect ratio

Related

Add a pattern repeated image as a background of another image using ImageMagick convert

I want to add a pattern repeated image as the background of another image that has spaces around. For example i have the pattern 200x200 and an image 1200x800. I have accomplished to add a background color.
The command i'm using to add a background color
convert -background "#333" -resize 768x450 -gravity Center -extent 768x450
Now i need to add a pattern instead of that color. Some suggest that i should make the pattern as one image with the maximum size then use it to add it as background image.
Is it possible to do it with convert or any other command using ImageMagick ?
Not sure what you mean, but I am guessing it's this. Let's make a 200x200 tile to start off with:
convert -size 200x200 radial-gradient:red-blue t200x200.png
And now you want to make a 1200x800 image by tiling that basic unit:
convert -size 1200x800 tile:t200x200.png BigBoy.png
If you now want to overlay a fine-art, high-quality, centred portrait over the top of your harmonious, subtle background, you can do this:
convert -size 1200x800 tile:t200x200.png -gravity center smiley.gif -composite BigBoy.png

Dividing Ground-penetrating radar profile through image processing

Please look at the attached image. It is a GPR profile and using image processing techniques, I am trying to divide this image into 3 zones by labeling with colors the whole image on the top:
when parabolas in the image are very clear and distinct with high pixel values - green zone/ line at the top
when parabolas in the image are blurred but visible - yellow zone
when parabolas are distorted or when not parabolas are present - red zone
What techniques should I use? What's the best approach to solve it?
I have tried various techniques but not with success in every case, because, as you can in the following image, sometimes the parabolas are too close to one another and identifying them is becoming an issue.
A sample of how I want to zone it: https://www.dropbox.com/s/9zm9epgf0gt7591/sample.png?dl=0
One of the tried code: simplest one.
clear all
clc
%read png image
H=imread ('origpng.png');
%convert to gray scale
I = rgb2gray(H);
I(I>150)=0;I(I<100)=0;
figure,imshow(I)
J=I;
J=255-J;
figure, imshow (J)
J(J<255)=0;
figure,imshow (J)
Your question is not very clearly posed, but I spent some time on it and felt like sharing my thoughts. I am not preteding for an instant that this is anywhere near a complete, or rigorous answer - just some musings that might give you some ideas. Also, I use ImageMagick, but if you have and know Matlab, you should use that - I am not suggesting you switch tools.
First, I did a Canny Edge detection like this:
convert http://i.stack.imgur.com/XITAE.png -canny 0x1+15%+50% canny.jpg
that gives me this:
I then "squash" that down till it is just 1 pixel high, which effectively totals up and averages all the columns - I make it 10 pixels high here so you can see it. Where it is white, there are lots of parabolas, elsewhere there are fewer.
Then I stretch that back up to the full height of the original image and blur it a bit - note that everything up to the following image is just one line of "code":
convert http://i.stack.imgur.com/XITAE.png -canny 0x1+15%+50% -resize x1! -normalize -resize 827x310! -blur 0x11 -colorspace gray mask.png
I then use the above as an opacity mask for a red image the same size as your original like this:
convert -size 827x310! xc:red mask.png -compose copy-opacity -composite colouredmask.png
Then I took your original image and coloured it with yellow like this by first creating a yellow image and then blending it onto your image and then I blended the red image from above on top of that:
convert -size 827x310! xc:yellow yellow.png
convert http://i.stack.imgur.com/XITAE.png yellow.png -compose colorize -composite colouredmask.png -compose overlay -composite result.png
giving
Obviously you can set different parameters and use different thresholds and things, but it kind of heads towards the sort of thing you are aiming it.
So the entire process is:
# Make mask of peaky areas - line 1
convert http://i.stack.imgur.com/XITAE.png -canny 0x1+15%+50% -resize x1! -normalize -resize 827x310! -blur 0x11 -colorspace gray mask.png
# Colour mask with red - line 2
convert -size 827x310! xc:red mask.png -compose copy-opacity -composite colouredmask.png
# Tint original image with yellow and then overlay semi-transparent red area
convert -size 827x310! xc:yellow yellow.png
convert http://i.stack.imgur.com/XITAE.png yellow.png -compose colorize -composite colouredmask.png -compose overlay -composite result.png
Notes
Squashing pixels... sorry for confusing you with my terminology! Basically, when I squash the pixels down to a single row, you need to imagine dropping a brick on the top of the image and flattening it down to just one pixel tall. So, essentially, you draw an imaginary line underneath the image and then you work across the image totalling up the number of WHITE (i.e. edge) pixels in each vertical column. Columns that have more white pixels will add up to larger numbers. Columns that have no white pixels will add up to zero. Once you have got the totals for each column, you find the highest total - let's say it is 32 and then you multiply all totals by 255/32 so that everything is normalized to 255, or white. Now the squashed strip represents the edge energy in each column. And I then use that as the opacity for the red when I overlay - so columns with more white edges in the Canny image will show up with more red in the result.
Let's demo what happens if I squash down to 10 pixels wide and 1 pixel high before scaling back up to the original size - basically it means that my resulting mask will have only 10 possible values (or columns) columns and that each column will be a single constant brightness. I'll put the Canny image underneath so you can see that the brightness of the squashed strip represents the edge energy:
convert http://i.stack.imgur.com/XITAE.png -canny 0x1+15%+50% -resize 10x1! -normalize -scale 827x310! mask.png
If you want to introduce another colour, you need to work out what your algorithm is for controlling where that colour should appear. You then do exactly the same thing again - you make a mask that is light where you want that colour in your output image and dark where you don't want that colour. Then you use that mask as the opacity for your new colour (as I did at the line labelled line 2 above) and then you overlay it like I did in the last line of my code above.

Imagick6 "-gravity SouthEast" while using -draw 'image [...]' failed

I have switch from Imagick version 5 to Imagick version 6 and noticed the following
While using the command:
convert -gravity SouthEast -draw 'image Over 0,0 0,0 overlay.png'
In version 5 the overlay.png is being added the bottom right corner (SouthEast) as expected!
But version 6 of ImageMagick failed and the position of the overlay.png is at the top left corner!
The command is used in typo3 "imgResource.params" http://docs.typo3.org/typo3cms/TyposcriptReference/Functions/Imgresource/Index.html
But I think this has nothing to do with the CMS, but with compatibility of im5 and im6
Anyone knows how to solve this...?
You can use this command instead:
convert background.jpg foreground.jpg -gravity SouthEast -compose Src_Over -composite output.jpg
So if this is our background:
and this is our foreground:
we get the following result:
Actually, I think he looks better on the other side of the image, but flopped to still face inwards :-)
convert background.jpg \( tiger.png -flop \) -gravity SouthWest -compose Src_Over -composite out.jpg
Updated Answer
Sorry to hear that the command doesn't work inside typo3. There is another version here that may work for you...
First get the width and height of the background and foreground images - I guess there is a way to do this in typo3, but I'll do it like this:
identify -format "%w %h" background.jpg
906 603
So the background is 906 px wide and 603 px high, and
identify -format "%w %h" tiger.png
258 296
the tiger is 258 px by 296. Then we can overlay using geometry like this, by subtracting the width and height of tiger from the width and height of the background to give an offset from top left of image:
convert background.jpg tiger.png -geometry +648+307 -composite out.png
which gives the same effect as gravity southeast. Maybe that will get you there...
Updated One Last Time
This one must get you there... just put the correct offsets in your original draw command rather than relying on gravity. So the first two numbers are the x,y offsets of the top left corner of the overlaid image from the top left corner of the background image, and the second x,y pair are the offsets of the bottom right corner of the overlaid image. So basically,
x1,y1 = width background - width overlay, height background - height overlay
x2,y2 = width background, height background
convert background.jpg -draw 'image Over 648,307 906,603 tiger.png' out.jpg

Imagemagick create thumbnail

I have an image that is 200x200 I want to trim the white space, and make it into an icon that is 32x32.
convert img.png -trim -resize 32x32 imgi.png
This line of code does not work, it will not make the canvas a uniform 32x32. I have tried taking it and adding -canvas 32x32 or -extend 32x32 but then the script does not work at all.
I am doing this from PHP with exec so I do not get an error back.
You can pad to tweak dimensions of the image after cropping. As of ImageMagick version 6.3.2 you can use -extent option to modify end result.
convert img.png -trim -resize 32x32 -gravity center -extent 32x32 imgi.png
For earlier versions it is necessary to play with -border, -crop and +repage.
convert img.png -trim -resize 32x32 -bordercolor white -border 16 -gravity center -crop 32x32+0+0 +repage img.png;

Maintain aspect ratio when converting video? - ffmpeg

I'm trying to convert movies from .avi to an iphone readable format
wherever I look, people suggest the following options for ffmpeg
ffmpeg -s 320x240 -aspect 320:240 [...]
This does not bode well for videos with a different aspect ratio!
How can I keep the aspect ratio from changing? Is there a way to set the size dynamically?
e.g. have the height to be 240 and the width variable?
Abstract from a rich article found here : http://www.frasq.org/en/transcoding-an-audio-or-a-video-file
To fit a video for a particular display, recompute its width and its height with the following formular:
aspect_ratio_of_display = width_of_display / height_of_display
aspect_ratio_of_video = width_of_video / height_of_video
if aspect_ratio_of_video > aspect_ratio_of_display
then
height = (height_of_video / aspect_ratio_of_video) and width = width_of_display
else
width = (height_of_display x aspect_ratio_of_video) and height = height_of_display
Remember to round the width and the height of the video to a multiple of 16.
Use a simple script in whatever language and get the video details, and adjust accordingly for a target size, you can also "letter box" or pad the top and bottoms for a better aspect ratio.
http://ubuntuforums.org/showthread.php?t=702188
http://stream0.org/2008/01/find-and-extract-video-file-de.html
http://www.mythtv.org/wiki/Ipod_export