Searching for large images made from a low resolution - image

I have many product images on my local drive that I got from different sources and some of them are messed up a bit. I'm talking about images that are large in resolution but it is apparent that this resolution has been achieved by resizing the image from a very small source.
Is there a software or something that could find these usualy high-res but low quality images? Thanks for any ideas.

I have a few ideas, and I'll show what I am getting at with ImageMagick which is installed on most Linux distros and is available (for free) for macOS and Windows.
Just to clarify what I am talking about, it is the lack of high-frequency information (detail) in images when they upsized (up-rezzed) from smaller images. Here is an example:
The technique goes like this. Take an image, copy it, scale it down to a percentage of its original size and then scale it back up and measure how much it differs from the original. Here is an example:
magick start.jpg -set option:geom "%G" \( +clone -resize 50% -resize "%[geom]"\! \) -metric MSE -compare -format "%[distortion]" info:
0.00220709
If I now do that in a loop, I can get the MSE ("Mean Squared Error") for resizing an image down to 10% and back up, down to 20% and back up, down to 30% and back up like this:
for ((size=10;size<100;size+=10)); do
distortion=$(magick start.jpg -set option:geom "%G" \( +clone -resize "${size}%" -resize "%[geom]"\! \) -metric MSE -compare -format "%[distortion]" info: 2>&1)
echo $size $distortion
done
Sample Output
10 0.00641669
20 0.00461728
30 0.00351362
40 0.0027639
50 0.00220709
60 0.00173019
70 0.00130171
80 0.000935031
90 0.000637741
If you run that again, but redirect the output to a file called "data", you can plot it with gnuplot:
gnuplot --persist -e "set yrange [0:0.01];set title '10: MSE vs Resize Percentage';plot 'data'"
Now, we come to the actual point. If I run the plot for a file that was up-rezzed from 75% of its original size, then again for a file that was up-rezzed from 50% of its original size, and again for 25% and 15%, I can put them together in an animation like this:
Hopefully, you can see that the purple points depart from the x-axis (where the MSE error is low) immediately at the point corresponding to the percentage of the original size from which the image was up-rezzed.
So, I am suggesting that you look at your images and find a threshold for the error that would correspond to the degree of up-rezzing likely to be present and then test the error for any individual image against that threshold.
This would be just the same if you are on Windows, all the code above is only for generating the plots and numbers to make animations. You just need to get the MSE with one line:
magick YOURIMAGE -set option:geom "%G" \( +clone -resize "${size}%" -resize "%[geom]"\! \) -metric MSE -compare -format "%[distortion]" info:

Related

Imagemagick input image to thumbnail squared image

As stated in the title i have to create a squared image starting from any kind of input image.
If the input image is smaller than thumbnail then i have only to pad it, otherwhise (if geater) should be shrinked without change aspect ratio) so for example :
After few test come up with the following code :
mogrify -auto-orient -define jpeg:fancy-upsampling=off:size={with}x{height}^> -thumbnail {with}x{height}^> -gravity center -extent {with}x{height}^> -background white -quality {dpi} -format {format} -path {path} *.*
Everything work as intended, except for few corner cases.
If the input image is really smaller compared to thumnail size, then the input image tend to disappear (because really small compared to thumbnail size).
So i am trying to figure it how to avoid excessive padding (only the strictly necessary to make the picture squared) when source image is smaller than thumbnail size (and so due to '>' command imamagick will not shrink it).

Batch Resize Photos While Maintaining the Aspect Ratio AND Fitting to a specific pixel size

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 ...

How to give an image an old, dusty appearance with faded colours?

I have images of old paintings. The paintings are old and dusty with faded colours as shown here.
How do I give any image this type of an 'old' appearance? I couldn't find any filters or openCV functions to achieve this type of look?
EDIT: My question is different as the other one solves the problem using the sepia filter and using the grain effect. I'm not looking for that sort of an appearance. I want my image to look like an old damaged painting. This means that the colours should be faded and it should have an overall dusty appearance.
There's no real need to write any code and use OpenCV, since you can do all that on the command-line with ImageMagick which is installed on most Linux distros and is available for macOS and Windows.
First, fading. This can be simulated by reducing the saturation of an image. So if we start with this Mona Lisa image:
We can fade her using this command to leave the brightness unchanged at 100% of its original value and reduce the saturation to 50% of its original value. I am intentionally "over-egging" everything so you can see it clearly. You should maybe be more subtle.
convert mona.jpg -modulate 100,50 result.jpg
Next, vignetting - or dark corners. You can use something like this:
convert mona.jpg \
\( +clone -fill white -colorize 100 -background "gray(50%)" -vignette 0x15+1+1% \) \
-compose multiply -composite result.jpg
The 0x15 controls the roll-off, or how gradual the change is, so increase the 0x15 if you want a smoother roll-off or go down to 0x5 if you want it harder. The +1+1% means that the ellipse will be 1% smaller than the width of the image and 1% smaller than the height of the image. So if you want a smaller light hole and bigger dark corners, go for +10+10%. The degree of darkening is controlled by the gray(50%) so you can diddle with that till you are happy too :-)
Finally, dust. Best thing is to get a PNG image of some dust, resize it to match the size of your image and overlay it.
First get the size of Mona:
identify mona.jpg
mona.jpg JPEG 403x600 403x600+0+0 8-bit sRGB 57130B 0.000u 0:00.000
So, she is 403x600. Here is a sample of some dust - again, you can be more subtle - I am just being heavy-handed so it shows:
Let's resize the dust to match and overlay it:
convert mona.jpg \( dust.png -resize 403x600\! \) -composite result.jpg
Then you can combine all three effects, fading, vignetting and dust, into a single command:
convert mona.jpg -modulate 100,50% \
\( +clone -fill white -colorize 100 -background "gray(50%)" -vignette 0x15+1+1% \) \
-compose multiply -composite \
\( dust.png -resize 403x600\! \) -composite result.jpg
If you have lots of images to process, you can script the whole lot to be done in parallel very easily with GNU Parallel - see some of my other answers for examples.
Keywords: artificial ageing, image ageing, command-line, command line, ImageMagick, magick, old, old photo, photo effect, convert, dust, scratches, fading, faded.
I would suggest using a style transfer tool, rather than manually coming up with a procedure to mimic the style of an old painting. There are plenty free style transfer tools and libraries available.
I would suggest using OpenCV various filters to create the effect you need. You have to try various filters and try to figure what works for you, But I have suggestions which you can try.
For color, fading try Erode and Dilate with small kernel size.
Next, add some noise, Salt and Pepper will do just fine, also try gaussian filter after applying noise. Salt and Pepper is non-linear noise and Gaussian is a linear filter so it will just spread the noise, but keep the filter kernel small.
Try finding some images of dust, torn page edges (WITHOUT BACKGROUND) like in the following link:
https://www.google.co.in/searchq=dust+png+images&newwindow=1&rlz=1C1CHBF_enIN797IN798&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjtq7ZvfPcAhXJO48KHQ2UD0kQ_AUICigB&biw=1536&bih=759#imgrc=_
Keeping alpha transparency in mind, mask these over your images.
With all the things in correct proportion and sequence, You will get your old dusty image.

gimp: resize and "unsharp mask" via script

I need to do the same operations for more than 60 files:
scale image
unsharpen mask
Is it possible to execute this from a script possibly passing the scale value ? I'm on Ubuntu if this could influence the answer.
edit:
What I need to do is to resize some Android icons from 64x64 to 96x96 (as far, maybe other resolutions too).
But these icons have already been blurred so, just increasing the size, I don't get a nice result.
I've seen that if I resize to 96x96 and apply the "Unsharp Mask" filter with the default values (Radius: 5,0 - Amount: 0,50 - Threshold: 0),
I get an acceptable result.
As you are on Ubuntu, you likely already have ImageMagick installed - convert, identify and mogrify commands, amongst others.
So, make a copy of your data and try something like this on a copy:
mogrify -resize 640x480 -unsharp 6x3+1+0 *.jpg
or maybe this
mogrify -resize 1024x768 -sharpen 0x1.0 *.tif
to resize all JPEGs to 640x480 max and sharpen them, and in the second case to resize and sharpen a bunch of TIFFs.
If you specify your GIMP parameters I can probably make closer suggestions.

Change Pixel Values of Image to remove Date

What is the most efficient technique to remove the date that a Camera embeds on any image it takes.
The task is to prepare a script/code/software that shall remove the date from the given input image file (jpeg, png).
Please let me know an optimum way to accomplish this.
Thank you.
Here is an alternative approach to the question. You can determine the average colour of the bottom right corner of the image (size 250px wide x 100px high) with Imageagick like this:
ave=$(convert sign.jpg -gravity southeast -crop 250x100+0+0 -scale 1x1 -format "%[pixel:p{0,0}]" info:)
That will give you the value srgb(199,181,119) for this image. Now you can create a rectangle (200px x 50px) that colour and overlay it onto the image and then blur the edges a little to blend it in:
convert sign.jpg \( -size 200x50 xc:"$ave" \) -geometry +970+780 -composite -region 240x90+950+760 -blur 0x10 out.jpg
I am not sure if you were hoping for something that is forensically indetectable or something that more or less removes the distraction somewhat. Hopefully the latter :-)
A little measuring around shows that the date is located at the following position:
150x40+650+520
i.e. 150 pixels wide by 40 pixels high, located 650 pixels to the right of the top left corner and 520 pixels down from the top left corner.
So, one approach would be to copy the piece of the image directly below that, and paste it on top of the date, which can be done in ImageMagick in one command like this:
convert sign.jpg \( +clone -crop 150x40+650+560 +repage \) -geometry +650+520 -composite out.jpg
That says... take the original image and create a copy of it (+clone), then cut out the piece specified after the crop command command and reset that as though it was the top left corner (+repage). Then paste (-composite) that image at offset +650+520 on top of the original image and save the result as out.jpg.
It is not a beautifully engiineered solution, but may be good enough. It may be desirable to blur the area a little, to help disguise it. Alternatively, it may be possible to select the colours within the date and make them transparent, then to displace the original image a little behind the transparent holes to fill them - I didn't choose that option because it is harder and because you may not like ImageMagick anyway, and there are actually several colours within the date field ranging from browns to golden yellows and selecting them without affecting the remainder of the image might start getting fun!
ImageMagick is free and available for Windows, OSX, Linux etc from here. It is ready installed on most Linux distros anyway.

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