Thursday, January 10, 2008

RSIZR Brings Seam Carving to Your Images

I just was just reminded (cause I needed it) of rsizr, a great little image resizing tool online that's based on seam carving technology rather than the basic scale and distort methods we normally use in Photoshop.

As most of us know, when you resize an image using traditional tools, you make everything in it smaller. But with rsizr, a Flash, browser-based application that lets you resize JPG, PNG, and GIF images, you can also resize your images using seam carving (a method of image retargeting). Seam carving analyzes your image and determines what detail is important and what isn’t. As you shrink an image the software eliminates the less important areas first, preserving the more important data.

Seam carving is a mindblowing image resizing technique pioneered by Shai Avidan and Ariel Shamir (now both at Adobe). Their algorithm alters the dimensions of an image by intelligently removing pixels from (or adding pixels to) an image, preserving the proportions and prominence of critical image elements while altering the shape and scale of the image around them. With this technique, it's now possible to reduce or enlarge pictures by a wide range, while still retaining details. For instance, if you need a horizontal image to go vertical, seam carving lets you change the image without rotation or spacial distortion (of your foreground objects anyway)

It's a little technical, admittedly, but the results are amazing:

This resizing technique first made waves last August when Wired posted a blog entry about the above video. But with rsizr's September 2007 release, seam carving became a practical reality on your desktop. To use rsizr, just upload the image you want to edit and then click the "retarget" tab and select the "preserve" brush. Now paint the portion of the image you want to preserve when you resize the image. Click done when you're satisfied and then use the sliders on the left side and top of the screen to shrink your image.

The results are pretty impressive, especially for a web-based implementation of seam carving. rsizr is a little counterintuitive at first – our seasoned interactive designers spent more than a few minutes trying to figure out how to reduce the scale of an image, for instance. And rsizr does have its limitations: Flash 9 imposes a 2880 pixel maximum in width and height for all loaded images. But once you get through the brief learning-period, rsizer is a powerful little tool that has greatly extended the utility of our image library.

And if you're a Flash developer that is interested in implementing this flexible image sizing technique on your own web site, the folks at rsizr have even provided information to help you dynamically implement seam carving on your website in much the same way they first developed the technique for

Seam carving opens up a whole new way to manipulate images and rsizr is just the tip of the iceberg. Expect to see it in CS4 (or CS10, at least...). FB

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