How can I write an image adapter class for a .bmp image?
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I'm trying to develop an image adapter class to accommodate some very large images with blockproc. I've tested the rest of my algorithms with a .tiff image and everything worked as expected but when trying to work with a .bmp file (what will be required for my project) I was unable to successfully write an image adapter class.
Here is the image adapter class that I've written and attempted to use.
classdef bmpAdapter < ImageAdapter
properties
Filename
Info
end
methods
function obj = bmpAdapter(filename)
obj.Filename = filename;
obj.Info = imfinfo(filename);
obj.ImageSize = [obj.Info.Height obj.Info.Width];
end
function result = readRegion(obj, start, count)
result = imread(obj.Filename,'Index', [1 2 3], ...
'Info',obj.Info,'PixelRegion', ...
{[start(1), start(1) + count(1) - 1], ...
[start(2), start(2) + count(2) - 1]});
end
function result = close(obj) %#ok
end
end
end
While using this adapter class with blockproc I'm receiving the following error messages:
Error encountered while executing the readRegion method of the bmpAdapter
class. The input arguments were:
region_start: [1 1]
region_size : [316 348]
The cause of the error was:
Error using imagesci\private\readbmp
Too many input arguments.
Error in imread (line 434)
[X, map] = feval(fmt_s.read, filename, extraArgs{:});
Error in bmpAdapter/readRegion (line 13)
result = imread(obj.Filename,'Index', [1 2 3], ...
Error in internal.images.AdapterDispatcher/readRegion (line 81)
data = obj.Adapter.readRegion(region_start, region_size);
Error in blockproc>getBlock (line 788)
source_data = source.readRegion(...
Error in blockproc (line 282)
block_struct = getBlock(source_dispatcher,block_struct,1,1,options);
I've gone through the following tutorial but haven't had much luck. http://blogs.mathworks.com/steve/2011/09/23/dealing-with-really-big-images-image-adapters/
Based on the error messages that I'm receiving my method is properly determining the starting positions to read the image data. Any help would be greatly appreciated.
Thanks,
Chris
0 Comments
Accepted Answer
Walter Roberson
on 19 May 2013
Those Name/Value pairs are defined for TIFF only. BMP is not defined with any Name/Value pairs, so you will need to strip them out before calling imread()
2 Comments
Walter Roberson
on 19 May 2013
Note: this does mean that if you want to read portions of a large BMP, then you might need to add complete BMP file format processing code, possibly written in another language.
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