http://forum.corel.com/EN/viewtopic.php?f=56&t=57341
NOTE: For those who don't know, content aware scaling, or seam carving, is a way to resize an image INCLUDING changing its aspect ratio if desired, as well as removing some unwanted objects if desired, without distorting important or even most elements of the image by only removing pixels that an algorithm determines are only of minor importance to the image. Google those terms to learn more and view videos of various software in action if interested.
In any event, I opened the subject image in both PSP X8 and Photoshop CS6 and applied the tool to the image leaving settings at default EXCEPT to tell the programs to resize to 479 px while maintaining the aspect ratio (leaving an image of 479 x 320 px). I did NOT use masking tools available to remove or preserve any of the important elements, but that can be done in both programs for more specific effect output. I then resized the original input image (without rescaling) to the same pixel size just to make comparisons of all 3 images (original, PSP Smart Carve and PS Content Aware Scale) easier. I have attached all three.
In this example, and with this particular image, I believe PSP did the better job by far. If you compare both scaled images with the resized original, you'll see that in the original the birds are somewhat centered vertically over the water between the river banks. In the PSP scaled image there is still water above and below the birds - i.e., between the river banks - while in the PS scaled image the birds are crowding the river bank at the bottom and top. As well, in the PSP scaled image there is some water space above the flying birds between them and the 3 birds that are swimming in the water so that the swimming birds are all still untouched parts of the image and remain intact.
Also, in the PS scaled image, the third swimming bird (the one at right) has been crowded out by one of the flying birds and has, in fact, been partially erased. (NOTE that using masks or selections to preserve that bird would have prevented it from being distorted - an option also available in PSP's tool), but I was going with defaults).
And last, because the river in the PSP scaled image hasn't been squeezed as much as it has in the PS scaled image, the overhanging trees in the upper river bank are more in proportion to the original in the PSP scaled image but take up a bigger percentage of the image in the PS result.
In BOTH scaled images, the two flying birds at the back of the flight are moved closer to the others because of the removal of the less vital water and trees elements that separates them in the original input image.
In my very limited opinion, and based only on this one single test with default settings, it appears that PSP made the most intelligent decisions overall. That is, the PS program seemed to decide (correctly) that the water of the river had the least "energy" (i.e., was less important overall) and concentrated on removing pixels in that element to resize vertically, replacing them with the more detailed overhanging trees, but this resulted in distorting the third swimming bird, crowding the flying birds between the river banks, and putting the overhanging trees out of proportion to fill the space.
On the other hand, PSP's invocation of the algorithm seems to have concluded that some of the water (those portions near the top and lower banks and near the third swimming bird) were energetic enough (perhaps given its proximity to more energetic pixels) and preserved them (maybe just to attempt to preserve the third swimming bird and keeping the flying birds from impinging on the river banks). In other words, it seems to have concluded that the third swimming bird's pixels (and those of the river banks) were of sufficient energy (therefore importance) that it had to preserve some water space between them and the flying bird that, in the Photoshop image, impinged on the swimming bird and the banks. But of course that's just my speculation.
It should be noted that PS has an option to set a Reference Point Location for the algorithm to use, and it defaults to the center of the image, so I'm just assuming that this is generally considered the best place for it in most circumstances. I definitely don't have time at present to experiment with changing that option to see how it affects the result.
In any event, however, I do think that Smart Carver in PSP did a better job of this particular project, but willing - and look forward to - hearing other opinions or advice on this tool. It is definitely one that has its uses - albeit most useful and effective when your image has lots of open space, such as outdoor images with lots of trees, sand, water, sky, and etc. - as you might find by doing some Google searches and watching some videos if it interests you.
IMPORTANT NOTE!: You'll see one important use of seam carving as a resize tool compared to regular resizing methods by comparing the images. Regular resizing (as I did on the original input image), makes the birds all somewhat smaller overall because their size is resized smaller in proportion to everything else in the image, even though it is the birds that are the main subject of the image. In the seam carved scaled images, the birds are larger relative to the rest of the image even though the overall image is resized to 470 x 320 pixels just like the original, so maintain their place as the important parts and focal point of the image. In fact, their presence is enhanced overall. Of course, it depends on the effect you're trying to achieve, and perhaps the background environment with the birds being only part of it might be just as important to you, the photographer, as the flying birds. It's all personal preference - and I admit I like the resized original better overall with the birds only part of the overall effect, but only as modified in @stormchaser's original thread (link early in this post) with the last two birds closer to the others in the flight.
