51–60 of 84 posts
Happy to see this here! Seam carving is one of those neat little algorithms that hit a sweet spot, being a sum of a few moderately complex algorithms, comes from a readable paper, and gives very satisfying result. I had a lot of fun implementing it in undergrad. One thing that I always wondered is how Photoshop managed to make it so fast that you can resize in real-time. If n is the width or height of the image, then…
Seam carving is fascinating, and especially the first version of the algorithm really really simple to implement. However, that algorithm introduces certain artefacts - the boat in this picture[0] makes it pretty obvious. The cause of these artefacts are mainly that the original algorithm did not look at energy that was introduced by removing a seam: each time this happens, the pixels adjacent to this seam become nei…
Happy to see this here! Seam carving is one of those neat little algorithms that hit a sweet spot, being a sum of a few moderately complex algorithms, comes from a readable paper, and gives very satisfying result. I had a lot of fun implementing it in undergrad. One thing that I always wondered is how Photoshop managed to make it so fast that you can resize in real-time. If n is the width or height of the image, then…
Do you really need to regenerate the whole dynamic programming table though? It seems to me that it could be kept more conservative and only recalculate the needed parts.
So, for a landscape-oriented image of aspect ratio 2:1 that would mean re-calculating up to 50% of its pixels. For narrower ones, that percentage is even higher, so not too much to gain.
Looks really interesting. I'd love to see an animated version that shrinks from large to small.
I wrote a version of this in javascript with a live demo you can play with at https://alexander.soto.io/seam-carving
With my tongue somewhat-in-cheek, I wanted to point you that you may want to be careful with that sample pic of the Eiffel Tower at night!
See: https://petapixel.com/2017/10/14/photos-eiffel-tower-night-i...
How well can it remove objects from images? Can it remove an object in a cluttered environment? I'm thinking of image augmentation for deep CNN's. Normally, augmentation can help with invariability to small rotations, translations and flips, but if we could remove objects from images, it might be useful for creating many examples from one image, for image based reasoning.
I remember first seeing content aware image scaling at Adobe MAX in Barcelona I think it was. We were completely dumbfounded by what was surely magic happening on stage. When they showed removing objects we just lost it, jaws on the floor and all. That was a fun conference.
http://gfx.cs.princeton.edu/pubs/Barnes_2009_PAR/index.php
(Licensed by Adobe for noncommercial research use only.)
Earlier quoted context omitted.
Do you really need to regenerate the whole dynamic programming table though? It seems to me that it could be kept more conservative and only recalculate the needed parts.
IIRC, the "energy" may affect up to 3 below pixels (left, right, center), so each pixel of a removed seam requires re-calculations downwards in the shape of a funnel going to the left and right with a maximum of 45°. In the worst case, this means re-calculatable pixels are in the form of a triangle with a top row pixel as its tip and a 90° angle there. So, for a landscape-oriented image of aspect ratio 2:1 that would…
I think they had this in Photoshop circa 1999, or I def. remember seeing a demo of it by Adobe around that time. Anyways, neat! Nice contribution.
I wrote a GUI for another seam carving library back in 2009[1], and it looks like although in archive mode, you can still access the source as well as the windows / mac binaries. Just tested it and it still works! Not as fancy as photoshop I'm sure, but does have the ability to paint a mask of regions to keep / remove to aid the algorithm and get the desired result. Multi-threaded too! [1] https://code.google.com/arc…
Thanks for that. I used it way back when(mid 2010) to make it look like a a 30' cliff jump was a 60' one. Really impressed my friends with it.
Happy to see this here! Seam carving is one of those neat little algorithms that hit a sweet spot, being a sum of a few moderately complex algorithms, comes from a readable paper, and gives very satisfying result. I had a lot of fun implementing it in undergrad. One thing that I always wondered is how Photoshop managed to make it so fast that you can resize in real-time. If n is the width or height of the image, then…
> In this paper, we present a more efficient algorithm for seam based content-aware image resizing, which searches seams through establishing the matching relation between adjacent rows or columns. We give a linear algorithm to find the optimal matches within a weighted bipartite graph composed of the pixels in adjacent rows or columns.
https://web.archive.org/web/20110707030836/http://vmcl.xjtu....