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matlabimage-processingbmp

bmpinfoheader for writing BMP images

I'm trying to write a MATLAB code for writing file to BMP file.

I know I can use imwrite() function. But my task is to avoid it.

I need info about how to write bmpinfoheader? So far I only know that it is 14-bits array.

Solution

  • 8-bit BMP

    %---- BitMapfileHeader
fwrite(fid, hex2dec('42'), 'uchar');     % 'B' in ASCII code
fwrite(fid, hex2dec('4D'), 'uchar');     % 'M' in ASCII code
fwrite(fid, 54 + sz + 256 * 4, 'ulong'); % file size
fwrite(fid, 0, 'ushort');                % always 0
fwrite(fid, 0, 'ushort');                % always 0
fwrite(fid, 54 + 256 * 4, 'ulong');      % offset
%---- BitMapInfoHeader
fwrite(fid, 40, 'ulong');                % BitMapInfoHeader size
fwrite(fid, width, 'long');              % image width
fwrite(fid, height, 'long');            % image height (negative; positive=upside-down)
fwrite(fid, 1, 'ushort');                % always 1
fwrite(fid, 8, 'ushort');                % color bit
fwrite(fid, 0, 'ulong');                 % compression
fwrite(fid, sz, 'ulong');                % image size
fwrite(fid, dpm, 'long');                % horizontal resolution (dpm)
fwrite(fid, dpm, 'long');                % vertical resolution (dpm)
fwrite(fid, 256, 'ulong');               % # of color index
fwrite(fid, 0, 'ulong');                 % # of important color index

    24-bit BMP

    %---- BitMapfileHeader
fwrite(fid, hex2dec('42'), 'uchar');     % 'B' in ASCII code
fwrite(fid, hex2dec('4D'), 'uchar');     % 'M' in ASCII code
fwrite(fid, 54 + sz, 'ulong');           % file size
fwrite(fid, 0, 'ushort');                % always 0
fwrite(fid, 0, 'ushort');                % always 0
fwrite(fid, 54, 'ulong');                % offset
%---- BitMapInfoHeader
fwrite(fid, 40, 'ulong');                % BitMapInfoHeader size
fwrite(fid, width, 'long');              % image width
fwrite(fid, height, 'long');            % image height (negative; positive=upside-down)
fwrite(fid, 1, 'ushort');                % always 1
fwrite(fid, 24, 'ushort');               % color bit
fwrite(fid, 0, 'ulong');                 % compression
fwrite(fid, sz, 'ulong');                % image size
fwrite(fid, dpm, 'long');                % horizontal resolution (dpm)
fwrite(fid, dpm, 'long');                % vertical resolution (dpm)
fwrite(fid, 0, 'ulong');                 % # of color index
fwrite(fid, 0, 'ulong');                 % # of important color index

    Source - http://www.h6.dion.ne.jp/~fff/old/technique/matlab/matlab_V.html

    Or look at the structure here

    http://msdn.microsoft.com/en-us/library/windows/desktop/dd183376(v=vs.85).aspx http://www.herdsoft.com/ti/davincie/davp3xo2.htm