imread / imwrite general graphics

[Stefan de Konink]

Hello,


I'm trying to do some schoolwork with Octave instead of Mathlab. And I
have some problems with some forge functions.

octave:4> I = imread('/home/skinkie/public_html/webcam.jpeg');
octave:5> imwrite('/home/skinkie/public_html/test.jpg', I);
error: transpose not defined for N-d objects
error: evaluating postfix operator `'' near line 177, column 10
error: evaluating assignment expression near line 177, column 8
error: evaluating if command near line 176, column 1
error: called from `imwrite' in file
`/usr/share/octave/2.1.72/site/m/octave-forge/image/imwrite.m'
octave:5> [r,g,b] = imread('/home/skinkie/public_html/webcam.jpeg');
error: element number 2 undefined in return list
error: evaluating assignment expression near line 5, column 10
octave:5> [r,g,b] = jpgread('/home/skinkie/public_html/webcam.jpeg');

octave:5> jpgwrite('test.jpg', I(:,:,1), I(:,:,2), I(:,:,3), 60);
error: octave_base_value::matrix_value(): wrong type argument `uint8
matrix'
error: octave_base_value::matrix_value(): wrong type argument `uint8
matrix'
error: octave_base_value::matrix_value(): wrong type argument `uint8
matrix'

octave:5> std2(I(:,:,1));
error: binary operator `-' not implemented for `uint8 matrix' by `matrix'
operations
error: evaluating binary operator `-' near line 84, column 31
error: evaluating argument list element number 1
error: evaluating binary operator `/' near line 84, column 66
error: evaluating argument list element number 1
error: evaluating assignment expression near line 84, column 14
error: evaluating if command near line 83, column 5
error: evaluating if command near line 78, column 3
error: called from `std' in file
`/usr/share/octave/2.1.72/m/statistics/base/std.m'
error: evaluating assignment expression near line 37, column 5
error: called from `std2' in file
`/usr/share/octave/2.1.72/site/m/octave-forge/image/std2.m'


So I guess, something goes wrong, after installing Imagemagick I managed
to get imshow to work. This must be gentoo specific, so I will make a
bugreport there.

octave:2> [I] = jpgread('/home/skinkie/public_html/webcam.jpeg');
octave:3> imshow(I)
octave:4> imshow(I(:,:,1))
octave:5> imshow(I(:,:,2))
octave:6> imshow(I(:,:,3))


So the images are actually in. But I'm missing things like: im2double,
im2rgb. Could this be the source of the problem? My version is 2.1.72,
compiled on a Dual Opteron with Gentoo.



Yours Sincerely,

Stefan de Konink



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