MATLAB: See I am executing the code at the link given, but why it is not working on a 512* 512 , 8 bit image

dwtimage size

http://in.mathworks.com/matlabcentral/fileexchange/39925-1d-2d-discrete-wavelet-transform/content/DWT/dwt.m While the code is working well with the given png image, also on 256 * 256 any 8 bit image but not with 512 * 512 image. why it is so?

Best Answer

I don't see any reason why the size of an image should make a difference to that code. It may be that your image is an indexed image, in which case that code will not work. To find out if it is an indexed image simply run this code:

>> [X,map] = imread(filename);

and then have a look at the variable map: if this is not empty then your image is indexed, and you will need to convert it to RGB/Grayscale before using that code, perhaps using ind2rgb.

Related Solutions

MATLAB: How to plot a variable density spiral(or any other mathematical 2D- graphs ) on to a image( 512* 512, zero matrix)

Here is an way by translating and scaling the random numbers.

N_k = 64^2;                         % number of k-samples
t   = linspace(0,sqrt(0.5),N_k)';   % dummy variable to parameterise spiral
k_x = (1 + randn(N_k,1)/20).*t.^2.*cos(2*pi*32*t);  % spiral kx-coords
k_y = (1 + randn(N_k,1)/20).*t.^2.*sin(2*pi*32*t);  % spiral ky-coords
% translate and scale the numbers to make them in range [0 512] 
k_x = 256 + 300*k_x;
k_y = 256 + 300*k_y;
% show scatterplot of trajectory
img = zeros(512, 512);
fig = figure();
ax = axes();
ax.Visible = 'off';
hold(ax);
imshow(img)
scatter(ax, k_x, k_y, 3, 'w', 'filled')

MATLAB: Cropping Watermarked image of 512 by % 512

I am assuming you want to crop about the center of the image. Give this a try (you might want to adjust using round, floor, ceil, etc... depending on your data)

I = imread('Test.png');
[rows cols dim] = size(I);
BB = [round(cols*0.375) round(rows*0.375) round(cols*0.25) round(rows*0.25)];
J = imcrop(I,BB);
subplot(1,2,1); imshow(I)
subplot(1,2,2); imshow(J)

Best Answer

Related Solutions

MATLAB: How to plot a variable density spiral(or any other mathematical 2D- graphs ) on to a image( 512* 512, zero matrix)

MATLAB: Cropping Watermarked image of 512 by % 512

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