I struggle to get good results extracting pencel drawings from photos with gimp.
I try approches like:
Adding an alpha channle and selecting white and deleteing. But this is unrellable as there is some shadeing preventing clean result no matter how much I play wit the settings.
The reuslt is also very washed out. So I try to increase its boldness by for example adding a glow fliter but again results are not great.
Does anyone have a recomendation what a good workflow might be.
I only have the photos now so I dont have the option to recapture the images with a scanner to even out the white of the paper.
With modern Gimp (2.10) the best option to even out the background is:
Decompose the image using Filters ➤ Enhance ➤ Wavelet decompose.
Replace the Residual layer by its own average with Filters ➤ Blur ➤ Pixelize (and use the layer size as the block size)
Related
I would like to convert images of blurred text, like this:
Into a quality similar to this, with sharp edges and not "pixilated":
Background: I'm currently working on pipelines to upgrade the video qualities of recorded classes. I intend to do that frame by frame. So far, I need a command to transform this category of images (mainly with text) into better-quality ones.
My problem is, I don't know and I didn't find any specific filters that could be helpful.
I'm trying to do image comparison to detect changes in a video processing application. These are two images that look identical to me, but are different according to both
http://pdiff.sourceforge.net/
and http://www.itec.uni-klu.ac.at/lire/nightly/api/net/semanticmetadata/lire/imageanalysis/LireFeature.html
Can anyone explain the difference? Eventually I need to find a library that can detect differences that doesn't have any false positives.
The two images are different.
I used GIMP (open source) to stack the two images one on top of the other and do a difference for the top layer. It showed a very faint black image, i.e. very little difference. I then used Curve to raise the tones and it revealed that what seem to be JPEG artifacts, even though the files given are PNG. I recommend GIMP and sometimes I use it instead of Photoshop.
Using GIMP to do a blink comparison between layers at 400% view, I would guess that the first image is closer to the original. The second may be saved copy of the first or from the original but saved at a lower quality setting.
It seems that the metadata has been stripped off both images (haven't done a definitive look), so no clues there.
There was a program called Unique Filer that I used for years. It is tunable and rather good. But any comparator is likely to generate a number of false positives if you tune it well enough to make sure it doesn't miss duplicates. If you only want to catch images that are very similar like this pair, then you can tune it very tightly. It is old and may not work on Windows 7 or later.
I would like to find good image checkers / comparators too. I've considered writing my own program.
Using GIMP, I am attempting to generate a large number of the same image but with different colors. In order to preserve the "shadowing", I am using the below steps. These steps get me exactly what I want in the end. The problem is, it's very tedious repeating them by hand over and over. There has to be a better way.
GIMP's batch scripting seems a little daunting, so I'm hoping to get some suggestions on how to automate this. Basically, what would be nice, is I'd like to essentially specify an array or list of colors...and then "automagically" perform the steps below to generate the output with the desired color.
Steps I'm doing by hand...
1.) Load a base PNG file that has an alpha channel.
2.) Add a new transparent layer.
3.) Activate the layer.
4.) Change mode to "multiply".
Then, for a range of different colors, I do the following...
5.) Select a foreground color.
6.) Apply bucket fill (fill similar colors, fill transparent areas, default threshold, fill by composite).
7.) Save the new PNG.
8.) Go to Step #5.
Here's kind of a cheesy representation of the effect I'm trying to achieve...
I'm also open to other non-GIMP suggestions as well.
Thanks for any and all help and suggestions.
I can offer you a nice Javascript example that do this.
try:
https://stackoverflow.com/a/9304367/1726419
there is a link there that actually do what you wand in JS - you can translate it to many other languages...
My ultimate goal is to get meaningful snapshots from MP4 videos that are either 30 min or 1 hour long. "Meaningful" is a bit ambitious, so I have simplified my requirements.
The image should be crisp - non-overlapping, and ideally not blurry. Initially, I thought getting a keyframe would work, but I had no idea that keyframes could have overlapping images embedded in them like this:
Of course, some keyframe images look like this and those are much better:
I was wondering if someone might have source code to:
Take a sequence of say 10-15 continuous keyframes (jpg or png) and identify the best keyframe from all of them.
This must happen entirely programmatically. I found this paper: http://research.microsoft.com/pubs/68802/blur_determination_compressed.pdf
and felt that I could "rank" a few images based on the above paper, but then I was dissuaded by this link: Extracting DCT coefficients from encoded images and video given that my source video is an MP4. Of course, this confuses me because the input into the system is just a sequence of jpg images.
Another link that is interesting is:
Detection of Blur in Images/Video sequences
However, I am not sure if this will work for "overlapping" images.
Th first pic is from a interlaced video at scene change.The two fields belong to different scenes. De-interlacing the video will help, try the ffmpeg filter -filter:v yadif . I am not sure how yadiff works but if it extracts the two fields and scale them to original size, it would work. Another approach is to detect if the two fields(extract alternate lines and form images with half the height and diff them) are very different from each other and ignore those images.
I'm trying to convert hundreds of images that
Have an unknown subject centered in the image
Have a white background
I've used ImageMagick's convert utility in the following way
convert ORIGINAL.jpg -fuzz 2% -matte -transparent "#FFFFFF" TRANSPARENT.png
The problem is, some of my subjects are within the "white" scale, so, just like the weatherman wearing a green tie, some of my subjects seem to be disitegrating.
Is there any way to solve this via ImageMagick? Are there any alternative solutions? Scripting GIMP?
As you said, GIMP has a magic wand tool that can be used to select continuous areas of the same color, and so it can avoid the "green tie syndrome". The problem is that it may introduce a problem if there is something like a human hair crossing the image (that will seperate some of the white areas). Another common problem, especially with pictures of people, is when they put their hand next to the body and between the hand and the body there is a small hole.
Basically, it is not too hard to create a GIMP script that opens in batch many images, uses the magic wand to select the pixel at some corner (or if desired, in several known fixed places, not just one) and then removes the selection.
If it's hard to find a white area at a fixed spot, it is possible to do a search inside - meaning that the script searches for a white pixel on the borders, and it goes inside gradually in a spiral untill it finds some white pixel. But this is very very unefficient in the basic scripting engine, so I hope you don't need this.
If any of the suggested options above is OK, tell me and I'll create a gimp script for it. It will be even better if you can post some samples images, but I'll try to help even without these.