CODEWITHSUNDEEP
imageimage-processing
Steve
Steve

Reputation: 4908

Obtaining the best quality from a resized image?

I have a set of beautiful pictures of oil paintings. The image resolution is typically 3000 x 2000 and I need to reduce these to 800 x 533 for display in a computer screen slide show. I've been doing an image resize with Irfan View, setting the horizontal dimension to 800 but I'm wondering if there might be a better technique that makes the resized image look better.

Thanks for any help.

Upvotes: 1

Views: 457

Answers (1)

skymandr
skymandr

Reputation: 150

There is an interpolation method often referred to as "sinc/lanczos" (sinc-filters are a family of filters, and Lanczos is the most common implementation), which is made to prevent precisely the blurring that can occur with bicubic and similar (monotonous) filters. It basically contains a sharpening mask in its definition, which enhances finer features. This method of resizing is available in ImageMagick (good free tool for batch-converstions), Gimp and PhotoShop, but I haven't been able to ascertain whether it is an option in Irfan View.

A very thorough introduction to Lanczos is given at Wikipedia: http://en.wikipedia.org/wiki/Lanczos_resampling

A more practical overview can be found in the (extremely extensive!) ImageMagick documentation: http://www.imagemagick.org/Usage/filter/#lanczos

As with all sharpening algorithms, it can generate artifacts (e.g. "ringing"), so in my experience it works best on rather busy images (such as oil paintings).

Upvotes: 2

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