Quality of Image after resize very low — Java

Question

In the script it is going from around the 300x300 mark down to 60x60. Need to improve the overall image quality as it is coming out very poorly at the moment.

Answer 1

dutchman, this is why I maintain the imgscalr library -- to make this kind of stuff painfully easy.

In your example, a single method call would do the trick, right after your first ImageIO.read line:

origImage = ImageIO.read(new File(sourceImg));

you can do the following to get what you want (javadoc for this method):

origImage = Scalr.resize(origImage, Method.ULTRA_QUALITY, 60);

and if that still looked a little jagged (because you are removing so much information from the image, you can add the following OP to the command to apply a light anti-aliasing filter to the image so it looks smoother):

origImage = Scalr.resize(origImage, Method.ULTRA_QUALITY, 60, Scalr.OP_ANTIALIAS);

That will replace all the remainder of the code logic you have. The only other thing I would recommend is saving out your really small samples as PNG's so there is no more compression/lossy conversion done on the image OR make sure you use little to none compression on the JPG if you really want it in JPG format. (Here is an article on how to do it; it utilizes the ImageWriteParam class)

imgscalr is licensed under an Apache 2 license and hosted on GitHub so you can do what you want with it; it also includes asynchronous scaling support if you are using the library in a server-side app and queuing up huge numbers of scaling operations and don't want to kill the server.