I have raw image data, a pixel array (actually a single string of data) that I want to convert to the most basic and minimal DNG format/file. I saw different approaches utilizing libtiff and libjpeg.
Is there a simpler and more straight forward way to do this in SWIFT using Core Graphics, Core Image or yet another SWIFT API?
The image data are still in the original Bayer matrix format (CFA pattern is RGGB) without any tags.
I downloaded the over 100 pages of the latest Adobe DNG format specification, but I cannot find the actual byte order or structure of the DNG file in there... I am pretty lost with this document.
Any help and hints are highly appreciated.
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I am working on a compression project, and I used the default save() function in Matlab for the purpose of lossless (entropy) encoding. The transform module is all figured out.
I used the save() function to encode a 3d array that includes a bunch of zeros. I am sure that Matlab is using some kind of lossless compression with the save() function since, when I save that array, it ends up taking far less space than an array, say, containing no zeros at all. I had no success finding out what type of entropy encoding schemes are behind the function. Because it is a core part of the algorithm, I think I must at least know what is behind the function.
Plus, if you know any other type of entropy encoder that would do a better job in compressing a 3d array that contains zeros, I would really appreciate you sharing. Or, if you think I could easily write the code for that myself, then please let me know.
The v7 format uses deflate.
The v7.3 format uses the HDF5 format, which supports gzip (deflate) and szip compression. It also has an option to not compress.
The MATLAB save function supports compression for some of the formats that are available. Specifically, -v7 (default format) and -v7.3 support compression. The details of the compression are not documented.
At work I have to record a lot of data from png data. Every time I have to manually record the digits (e.g. mean\SD 101.1\11) on the excel sheet and read it with Matlab. Would it be possible that Matlab could directly read the digits from the PNG image, so that lots of work could be saved?
I know it might involve pattern recognition, but still hope that there may be someone who has done this before.
You can make use of Optical Character Recognition (OCR). The code for it is available here
I'm trying to convert a 3-channel rgb raw image to a one channel image in Matlab (or any other conversion software for that matter). I've tried concatenating but that was still unsuccessful. Any other suggestions?
The raw image I found online and I personally don't care which format it's in (whether NEX/ARW/etc). Just need to get it to one channel.
Thanks
;)
if you wanted encode 2mb of data onto a 2d-bar code, which 2-bar code would be good to starting point or recommend.
There are lots and different types of 2dbar codes out today,Aztec 2-d barcodes,maxicodes,Pdf417,Microsoft HCCB,vericodes....etc...lots.... all unique in their own way.
i guess in a nutshell my questions is.... which barcode would make a good start off point to encode 2mb of data??
i tried reading through the Qr code international standard turns out even # version 40L the most amount of data you could encode is on to a Qr code is
1) numeric data: 7 089 characters
2) alphanumeric data: 4 296 characters
3) 8-bit byte data: 2 953 characters
4) Kanji data: 1 817 characters
which are all a far cry from the 17million bits thats is 2mb
my goal was to create something like
http://realestatemobilemarketingsolutions.com/wp-content/uploads/2012/07/real-estate-mobile-marketing.png
After you scan the barcode you can view photos of the house/property on your phone, you dont have to walk-in or wait for an open home,20 photos # 100kb each is about 2mb
Even if you could create a single 2D barcode which will encode the whole thing, the user won't be able to scan the whole thing in one go. No one has a cellphone imager which will support that kind of resolution. Your best bet is to do a QR-code with a URL in it.
Things like DataMatrix and QR-codes are extensible. You have a limit to how much data can be encoded into one block, but you CAN create a code which has multiple blocks. Indeed, if you look at this page, you'll see a discussion of using pages full of 2D barcodes as a form of data backup. They were able to fit up to 1/2 MByte of raw data into a single page. That's at 600 dpi, which will require a scanner (not a smartphone) to decode.
From what I've been reading, DataMatrix tends to have less overhead and, therefore, will stuff more (payload) data into a square inch for a given DPI. You would need a mobile app capable of shooting multiple images (tiles) of a very large image and either:
compositing the individual images into one large one for decoding OR
decoding each of the smaller blocks and reconstructing the original data from the pieces
I know of no app which will do that.
I've pondered providing bulk data via 2D barcodes. I was pondering publishing a mobile app in a magazine and providing a way for people to "download" the app from the magazine, without needing to provide a website / FTP site where they could download it. I'd first need to provide an app which could decode such a monster. Then, the end user would have to be patient enough to scan the whole thing. Good luck with that.
I MIGHT be able to provide a large 2D barcode containing a .torrent file and then using existing BitTorrent apps to download the resulting app; I have a .torrent for a recent Linux Live-DVD where the .torrent is < 32 KB.
A chunk of data (an app or images) in the MB or larger range ... really not feasible through this channel. The megabytes of data you're wanting to provide ... again ... really not feasible through this channel.
Voiceye Code is the highest density 3d code I have been able to find. Works well too, but code making software is price prohibitive to screw around with. 500.00 (ish)
How about using some variant of DataGlyphs, which has a lot in common with steganography? In other words, you use a greyscale image to also store your data...
I have developed a reader for JAB codes that can read whole audio file from a codebar. JAB codes are very high capacity due to polychrome nature.
More on this here
I am dealing now with DDSM database (Digital Database for Screening Mammography) .. its disadvantage is its extension. It is extension is ljpeg (lossless jpeg) which it is very poorly supported extension. I want to read them using matlab or converting them to any other type which is widely supported. thank
I know there is a working version of DDSM's jpeg program for linux at http://www.cs.unibo.it/~roffilli/sw.html
I compiled and tested it. I used the MATLAB code as described here to view the images.
It displays correctly only for some scanners.
As described in the paper http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.111.3846
When properly compiled, the DDSM software outputs the image data as a stream of raw bytes; one then has to normalise these according to the model of digitiser used to image the original films and then create an image file that is readable by one’s image analysis software environment.
*EDIT: *
I found a complete solution that downloads, normalizes (based on the scanner) and converts the DDSM image to PNG format. Dr. Chris Rose wrote that program, please download it on his website
http://microserf.org.uk/academic/Software.html