enbergs / matlab-readraw

Read RAW camera images from within Matlab, using DCRAW

matlab-readraw

Read RAW camera images from within Matlab, using DCRAW

The use of this class boils down to simply creating the object. Then, you may simply use the imread and imfinfo call as usual, and RAW files will magically be handled.

Example:

In the following example, we just call readraw once, and then all is done with imread and imfinfo as you would do with other image formats.

readraw;
im   = imread('file.RAW');  % this creates a file.tiff
info = imfinfo('file.RAW'); 
delete('file.tiff');  % to save disk space, if ever needed
...
delete(readraw);

The default DCRAW setting for the importation is '-T -4 -t 0 -v' to get the raw data.

NOTES:

NOTE: Each RAW file will be converted to a 16-bits TIFF one at the same location as the initial RAW file. This file is then read again by imread to actually get the image RGB channels. If you have created these files (which are each 146 Mb for 6x4k images), you may either remove them, or further access them without requiring conversion.

Supported RAW camera image formats include:

• RAW CRW CR2 KDC DCR MRW ARW NEF NRW DNG ORF PTX PEF RW2 SRW RAF KDC

If you wish to import the RAW files with specific DCRAW options, use the readraw class method 'imread' with options as 3rd argument e.g:

dc = readraw;
im = imread(dc, 'file.RAW', '-a -T -6 -n 100');

and if you wish to get also the output file name and some more information:

[im, info, output] = imread(dc, 'file.RAW', '-T -4 -t 0 -v');

Some useful DCRAW options are:

• -T write a TIFF file, and copy metadata in
• -w -T -6 -q 3 use camera white balance, and best interpolation AHD
• -a -T -6 use auto white balance
• -T -4 use raw data, without color scaling, nor white balance
• -i -v print metadata
• -z set the generated image date to that of the camera
• -n 100 remove noise using wavelets
• -w use white balance from camera or auto
• -t 0 do not flip the image

Methods:

• readraw class instantiation. No argument.
• compile check for DCRAW availability or compile it
• delete remove readraw references in imformats
• imread read a RAW image using DCRAW. Allow more options
• imfinfo read a RAW image metadata using DCRAW

Credits:

• DCRAW is a great tool https://www.cybercom.net/~dcoffin/dcraw/
• Reading RAW files into MATLAB and Displaying Them http://www.rcsumner.net/raw_guide/
• RAW Camera File Reader by Bryan White 2016 https://fr.mathworks.com/matlabcentral/fileexchange/7412-raw-camera-file-reader?focused=6779250&tab=function

Installation:

Copy the directory and navigate to it. Then type from the Matlab prompt:

addpath('path-to-readraw')
readraw;

If DCRAW is not yet installed on the computer, you will need a C compiler. The DCRAW C source file (provided with READRAW) will be built and used.

License: (c) E. Farhi, GPL2 (2018)