For an application we are developing it is important for us to know how much data (in bytes) is stored in a JPEG2000 code stream for each resolution and quality layer. Does anybody know an application / library that can easily reveal this information?
Take a look at the free JP2 Metadata Editor:
http://j2k-codec.com/mde.html
It doesn't show you data by resolution but at least it shows you the compressed codestream size for each tile. Maybe it will be helpful to you.
I have been using jpylyzer and/or pirl (jp2info) in those cases.
Related
I have an undocumented tiff image which I need to use with a software that can read only geotif files. my simplest idea was to pretend the image is at 0N, 0W with a pixel size of 0.00000899928° (1m) in both directions.
I have rea the thread here but I was unable to reproduce the answer.
Thanks for helping. I am a dummy in geodesics, GIS and the like.
You are attempting to georeference a raster, which is often a difficult task, with multiple techniques. It's not possible to provide an answer for your question given the information you have supplied. Also, never assume that lengths in degrees can be converted to lengths in metres (the Earth isn't flat).
Search around GIS.SE for ideas , e.g. using the [georeferencing] tag. There are tools available with QGIS to help manually georeference rasters to other geospatial data.
I need to convert scanned document images to a PDF document with high compression. Compression ratio is very important. Can someone recommend any solution on C# for this task?
Best regards, Alexander
There is a free program called PDFBeads that can do it. It requires Ruby, ImageMagick and optionally jbig2enc.
The PDF format itself will probably add next to no overhead in your case. I mean your images will account for most of the output file size.
So, you should compress your images with highest possible compression. For black-and-white images you might get smallest output using FAX4 or JBIG2 compression schemes (both supported in PDF files).
For other images (grayscale, color) either use smallest possible size, lowest resolution and quality, or convert images to black-and-white and use FAX4/JBIG2 compression scheme.
Please note, that most probably you will lose some detail of any image while converting to black-and-white.
If you are looking for a library that can help you with recompression then have a look at Docotic.Pdf library (Disclaimer: I am one of developers of the library).
The Optimize images sample code shows how to recompress images before adding them to PDF. The sample shows how to recompress with JPEG, but for FAX4 the code will be almost the same.
How to parse a captcha Image or get data from it? The data is part of image. The data changes with reloading. How to get the data on the image? can i do anything with data-url of image?
following is a example for captcha:
http://enquiry.indianrail.gov.in/ntes/CaptchaServlet?action=getNewCaptchaImg&t=1400870602238
Using OCR (Optical Character Recognition) is the first step. Below are 2 examples for such tools/APIs that can help you with that.
Try Tesseract.
Tesseract is probably the most accurate open source OCR engine
available. Combined with the Leptonica Image Processing Library it can
read a wide variety of image formats and convert them to text in over
60 languages.
for more info check: https://code.google.com/p/tesseract-ocr/
You can also try OCRopus
OCRopus is an OCR system written in Python, NumPy, and SciPy focusing
on the use of large scale machine learning for addressing problems in
document analysis.
for more info check: https://code.google.com/p/tesseract-ocr/
For detailed info with code smaple on how to do this, check Ben Boyter's article Decoding CAPTCHA’s at: http://www.boyter.org/decoding-captchas/
I am trying to bring an Indian Magazine online. This magazine is typed in CorelDraw using the proprietary Devenagari font (http://www.modular-infotech.com/html/shreelipi.html). So these guys have provided a USB dongle that you have to have attached to the machine when you want to access the fonts, and this software has been in use for past 10 years.
To put the magazine online, we've tried to convert it to pdf (by printing). The resultant pdf size is of the order of 30-50MB, even when the pdf does not have even a single image. I am guessing it converts the whole text into an image
It would be really difficult for users to read this magazine given its size. Though when I convert it to .swf format (for add flipbook kind of functionality) - the size reduces to 5-6MB. But there are people who like to download the magazine and then read. I have had no luck reducing the size of pdf.
I have done lot of research on web. The postscript, primo pdf do not help much. The best I could get was 30% reduction using DocuCom pdf printer. But it is still 20MB. I have tried to play with resolution, compression and quality but the best I could get was 18MB.
Ideally I would like to reduce it to less than 2MB.
I would be really grateful if you could help me reduce the size of the pdf! Considering that it has no images, I am hopeful that I can get some really good compression.
The (35MB) magazine can be downloaded from: http://merajhola.in/jin-march.pdf
I can't see any easy way to reduce the size of this PDF. There are no embedded fonts and all the text is drawn using vector graphics primitives. No amount of tweaking the resolution, compression and quality will have a significant improvement.
One possible option would be to embed the font as a subset rather than use vector graphics. That will almost certainly make a big difference, however I doubt the proprietary font license will allow it.
I'm sorry, but this Shree-Lipi thing just sounds wrong in 2012. It would be much better to use proper OpenType fonts with modern (say InDesign) or free (say LuaTeX) software.
Anyone know of an lossless image compression api/service similar to smushit from yahoo?
From their own FAQ:
WHAT TOOLS DOES SMUSH.IT USE TO SMUSH IMAGES?
We have found many good tools for reducing image size. Often times these tools are specific to particular image formats and work much better in certain circumstances than others. To "smush" really means to try many different image reduction algorithms and figure out which one gives the best result.
These are the algorithms currently in use:
ImageMagick: to identify the image type and to convert GIF files to PNG files.
pngcrush: to strip unneeded chunks from PNGs. We are also experimenting with other PNG reduction tools such as pngout, optipng, pngrewrite. Hopefully these tools will provide improved optimization of PNG files.
jpegtran: to strip all metadata from JPEGs (currently disabled) and try progressive JPEGs.
gifsicle: to optimize GIF animations by stripping repeating pixels in different frames.
More information about the smushing process is available at the Optimize Images section of Best Practices for High Performance Web pages.
It mentions several good tools. By the way, the very same FAQ mentions that Yahoo will make Smush.It a public API sooner or later so that you can run at it your own. Until then you can just upload images separately for Smush.It here.
Try Kraken Image Optimizer: https://kraken.io/signup
The developer's plan is free - but only returns dummy results. You must subscribe to one of the paid plans to use the API, however, the Web Interface is free and unlimited for images of up to 1MB.
Find out more in the Kraken documentation.
See this:
http://github.com/thebeansgroup/smush.py
It's a Python implementation of smushit that can be run off-line to optimise your images without uploading them to Yahoo's service.
As I know the best image compression for me is : Tinypng
They have also API : https://tinypng.com/developers
Once you retrieve your key, you can immediately start shrinking
images. Official client libraries are available for Ruby, PHP,
Node.js, Python and Java. You can also use the WordPress plugin, the
Magento 1 extension or improved Magento 2 extension to compress your
JPEG and PNG images.
And First 500 images per month is for free
Tip : Via using their API, you have no limit about file-size (not max 5MB each as their online tool)