I want to build an upload applet / desktop client that can resize - trim and then send an image to my amazon s3 bucket.
Trimming my images has proven to take the longest and be the most cpu intensive. On my server when a user uploads a image using an html form I use imagemagick command line tools to do the trim and resize.
What tools would you guys recommend using?
Edit: I need to be able to automatically crop images. Something similar to the imagemagick trim function.
I would recommend that you check out JAI.
Specifically check out the classes CropDescriptor, ScaleDescriptor and their static methods.
Also, take a look at the subclasses of OperationDescriptorImpl, they will give you an idea of the types of operations JAI is capable of.
Related
How reliable is ZXing's barcode localization for DataMatrix decoding compared to libdmtx?
I have a set of png image files of stickers (proprietary, so unfortunately I'm not able to share them) containing DataMatrix barcodes. These stickers sit on flat surfaces, have very nice quiet zones and are generally centered in the image, but suffer from inequal lighting conditions and slight dust, likely the largest obstacle to reliable decoding.
I'd like to use a modifiable Java library to decode them and it seems that ZXing is the only open-source option (open to other suggestions). However, upon running these images through the ZXing online decoder, I consistently get NO BARCODE FOUND, even on the cleanest images. In contrast, when I run the same images through proprietary online decoders, like Inlite's Free Online Barcode Reader, I get reliable decodes for all the images. My company has implemented a library in C that also reliable decodes the barcode images by processing them and calling libdmtx. Similarly, this online DataMatrix decoder built on libdmtx can also reliably read my image files.
Is the barcode localization in ZXing significantly inferior to libdmtx?
If I attempt the same preprocessing on the image files before I run them through ZXing, could I achieve similar results? I have a strong preference for a Java library (ZXing), but I may have no choice but to use libdmtx. Would appreciate any insight, thanks!
I had similar problem as you but on encoding side. As per my findings Zxing is certainly inferior to Libdmtx. We are using both libraries in house in C++ and Java project.
There is a case when Zxing breaks while generating barcode look at my comments here:
https://github.com/zxing/zxing/issues/624
However Libdmtx works flowless. The other free options you have in java world are (they are for encoding):
barcode4j
OkapiBarcode
Another alternative is the relatively new ZXing cpp port here: https://github.com/nu-book/zxing-cpp.
It contains a completely new DataMatrix detector that was meant to fix serious limitations of the Java upstream version. It was specifically designed to deal with low resolution images (module size as low as around 2 pixels) and symbols that have just the required 1 module quite zone and a busy background.
The following comparison is certainly not 'fair' but I just had the dmtxread utility of the libdmtx try my test set of images and it missed 3 of 17 samples and took a whooping 300 times as long compared to my code :).
I am currently working on a website which involves a lot of images. The problem is all the images are uploaded by the user so I can't do anything to alter the images. The website runs quiet ok on local system but the speed drops too much on the server,it becomes too slow
I'd suggest you to use Timthumb. It creates a thumbnail by generating a URL on the fly and uses very minimal disk space.
If the users of your website are uploading the images, then I presume (there must be) an upload script. Inside of that script or directly after its execution you could compress or rescale the image to size needed on the website, shortening loading time. There is a PHP image processing library called ImageMagick here:
http://php.net/manual/en/book.imagick.php
There is the PHP GD image processing library here:
http://php.net/manual/en/book.image.php
I don't have much personal experience with them, but from my knowledge it looks like one will do the job. Off the top of my head, that's the best solution I can think of, and hopefully it works. There is not a lot you can change about your problem if you don't compress/scale the images, and these are probably your best options. Wish you the best.
Having an ecommerce website, We have thousands of product images. On checking pagespeed on google it shows me something like this:
I was wondering, if there is any built in feature in Java or any third party library is available with which we can losslessly compress all the images that we host. Hence we can save few KBs of our customers.
On searching through internet I found few like punnypng and kraken which are paid, hence we do not have heavy image uploaded every month, subscribing to them is not worth. I would prefer any built in feature in Java or any open source third party library.
I came across JAI, but not sure about whether it addresses this problem or not. Anyone with hands-on experience with this?
P.S. We are using Java 8
Have you looked at classes in the javax.imageio package (http://docs.oracle.com/javase/7/docs/api/javax/imageio/package-summary.html) ?
You can do decoding and re-encoding of the images. The class ImageWriteParam (http://docs.oracle.com/javase/7/docs/api/javax/imageio/ImageWriteParam.html) lets you customize the compression settings.
~600 KB jpeg images are quite large for screen, though not for print. Having several images on a page would mean making more or less "thumb" views being smaller. And provide an individual product page with higher resolution, say 600 KB JPEG.
Standard ImageIO suffices for conversion, see #NicolaFerraro.
Faster page loading can be achieved on the overview page with multiple images, by storing the smaller views into one large image. PNG might then be appriopriate to prevent JPEG artifacts.
To provide a higher resolution for a print, one can use the CSS media setting.
Check thumbnailator. It is great at making smaller images from larger images.
Besides you should consider when you are going to make these smaller images. At each call, at the first call (any keeping a cache), ...
I am using a java applet in my web project and some images are shown in this java applet.
I want to limit users to pull images from the web page. What are possible techniques for a client user to save images used in a java applet which is used in a browser session, except "print screen"?
Any ideas are welcome.
Thanks.
..What are possible techniques for a client user to save images used in a java applet
I don't know about typical end-users, but I'd do these things to circumvent several security strategies:
1. Hide them in the archives
Look at the source of the page
Discover the location of the Jars
Download each one by direct fetch
Rename them to .zip and expand them (quick & dirty), then..
Sell your images for causing me that much inconvenience to get them in the form I want.
That last part was sarcasm (mostly), but just wanted to make the point that if you put something in a Jar, people can get it out.
2. Hide them on the server
Use a packet sniffer to discover the image locations by URL.
Pull each image directly (etc.)
3. Encrypt the images
You might use techniques to encrypt the images, then obfuscate the code that decrypts them, but that would also fail against a determined hacker.
4. Screen grab
As mentioned already. 'Last resort' - crude, but effective.
..Any ideas are welcome.
Don't pursue such strategies. You won't achieve any form of security worth having, it will just irritate the user.
If the image is a bitmap inside of a jframe it'll be hard to capture it without resorting to a screen grab. Just like using it in flash the image file itself won't actually exist anywhere on the client.
I am working on google appengine to create a tool for comparing image similarity.
I need to extract the pixel values of each image to perform this.
Unfortunately appengine does not support the java image libs.So I am unable to proceed.
Is there any appengine safe image library in java capable of extracting image data?
I saw some techniques in python but dont want to switch to python if I can do it in java somehow...
GAEJ has its own graphic library with fairly limited features and java.awt.image.BufferedImage is a restricted class (ie, java.awt.Image is not supported and still not present in the Jre Class White List ).
There's an open issue here, that you might want to star.
EDIT:
Somebody has patched pngj to work with InputStream.(You could use it to read a PNG pixel by pixel)
The new version of pngj now an alternative pngj-sandbox.jar that only references whitelisted classes, it should run in google-app-engine.
can https://github.com/witwall/appengine-awt help to you? i believe it willbe enough to add theis lib as dependency to the project to make BufferedImage working (but havent' tried this yet)