Photo Enlargement - Photo Enhancement Through Image Resizing

[donhdefl]

Photo enlargement of digital pictures is done through a process called interpolation: the computation of pixel color values between the pixels that already exist. A pixel is the smallest element of an image or picture on a computer screen - usually it is a single-colored dot. All software programs that perform photo enlargement use the following pixel interpolation methods to enlarge pictures:

- Nearest neighbor interpolation
- Bilinear interpolation
- Bicubic interpolation

These photo enlargement methods and some new technologies that go beyond them are described below. The following image was the image used to show these photo enlargement method differences. The marked area was enlarged 300% in subsequent examples.

http://photoenlargement.imagener.com/images/main2.jpg

Nearest Neighbor Photo Enlargement Method

The value of the new pixel is made the same as that of the closest existing pixel. When enlarging an image the pixels or dots of color are duplicated to create new pixels increasing as the image grows. This is the least accurate method of enlarging an image, and this is obvious when you look at an image that has been enlarged using this method. This method creates obvious pixilation - edges that break up curves into steps or jagged edges, also called "jaggies." Nearest neighbor photo enlargement yields the least desirable result.

http://photoenlargement.imagener.com/images/nn.jpg

Bilinear Photo Enlargement Method

Bilinear interpolation is the next step up toward a more visually satisfying photo enhancement result. Bilinear reduces pixilation by filtering the surrounding pixels to smooth out jaggies giving the image edges a smoother look. Color values from the four surrounding pixels are sampled and filtered to provide the color value for the new pixel added during enlargement. Contrast between the jagged edges produced by the nearest neighbor enlargement method is reduced because of averaging neighboring values together.

http://photoenlargement.imagener.com/images/bl.jpg

Bicubic Photo Enlargement Method

Bicubic interpolation goes a step further than the previous two methods, analyzing the 16 pixels around each individual pixel using that information for enlargement. The weighted average of the closest 16 pixels (a 4x4 matrix) is calculated based on distance. This is the method most commonly used by popular photo software packages, and by printer driver software and many digital cameras for enlarging images. It produces smoother results but enlargements above 120% to 150%, quickly degrade in quality and become blurry.

http://photoenlargement.imagener.com/images/bl.jpg

This is the limit of the ability of all commercially available photo software, even software costing several hundred dollars. There are many software packages that have lots of functionality for manipulating images, but when it comes to photo enlargement, the above three methods have not been improved upon within their released versions.

Entire article: http://photoenlargement.imagener.com

Hope this helps...

-dh

[ScottE]

You quit quoting from your linked website part way through. The subsequent examples of three Kneson products are all superior to bi-cubic resampling, although the Progressive ++ example looks a little over-sharpened.

I suggest you download a copy of Qimage and experiment with their Vector or Pyramid resampling algorithms. Both do a better job than bi-cubic for big enlargements. Qimage is not a very expensive program. Just beware that because of the number of calculations required, both these methods use a lot of computer time.

The description of Kneson's Unlimited Enlargement Method appears to use a vector method and give the best results posted on the website.

[Hellashot]

What's the point of this post? The best program I've heard of to properly enlarge images is called Genuine Fractals.

Never used it though.

[Scottes]

What's the point of this post? The best program I've heard of to properly enlarge images is called Genuine Fractals.

Genuine Fractals is extremely good, but not the best. No program is from tests I've done so far. It all depends on the image. I've done tests and some images are btter with SmartScale, others with genuine fractals, but most were better with plain old PhotoShop.

I have yet to try Qimage, though. Next time I need a large print I plan on using it, but I don't want to waste a trial period just playing with it.


But it all depends on the image from what I've seen so far. And so far I'll stick to PS (though I will try Qimage).

[Headcase650]

Im sure you all know this, with photoshop cs there are 3 versions of bicubic. the normal one that it had in version 7, and 2 new ones for CS, bicubic smoother is for upsizing and bicubic sharper is for downsizing.

[mbze430]

Just a revisit of this subject. Imagener Unlimited ($99) version does support Raster to Vector interopolation method, much like Qimage. It is worth a try to large enlargement with this new version.

[Avalonthas]

Adobe should purchase there technology so it will steal even more market share away from Jasc and other competing companies

[BigRed450]

Been There, Done That, .... for my money I will stick with PS 7.0 or CS Resize Wizard Thank You. It does an awesome job and unless you are printing bulletin board size prints its not likely you'll be able to tell the difference. Sure, You can magnify test samples to 300, 400, 500 %, on your monitor, but you'll not see a difference in print. I regularily print 13x19" and have 20x30" done.

[panpioneer]

to user donhdefl,
I saw you posted 10 messages talking about the same product called Imagener which satisfied you very much. I ordered one online and it never worked-- not even load image correctly nor did t change anything in the image. So, I wonder if you could tell us how you got a working version? Since the company does not have a customer support phone line, but only an email address which rarely responds to any question. So, I wonder if you know how to get momey back?

[DavidW]

You've posted in a thread that's ancient - the member to whom you addressed your question hasn't posted for over a year. If the software doesn't work and you can't get any satisfaction from the company, I'd contact your payment card company.


For what it's worth, I've never heard of this software - though I have heard of Qimage and Genuine Fractals.



David

[DavidW]

When looking furhter, I found a phone number on this page (http://www.imagener.com/Request/index.html) of the Imagener web site.



David