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keep getting error in the covariance: Subscript indices must either be real positive integers or logicals.
It looks as if you have used *cov* as the name of a variable. Do which cov to see if this is the case. You should see...

11 years ago | 2

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Answered
how to make a colorwheel in matlab?
The functions you need are meshgrid, atan2 and hsv2rgb. Possibly also hypot if you want to make the centre bright or dark.

11 years ago | 0

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unexpected figure with inverted child photo pops up when i run my code
It's because you are assigning a value to *img* but using the value of *image*, which has the side effect of displaying the boy....

11 years ago | 0

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Why does it not calculate x & y for all values of t?
Your code process all the values of t - the problem is that the calls to disp are outside the loop, so they only show the values...

11 years ago | 2

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Answered
Cylinder unwrapping with imtransform
I haven't tested this, but here's a quick thought: try replacing f = @(x, unused) arcsin(1/x); with f = @(x, unused...

11 years ago | 0

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Answered
How to assign an element of a column array to a variable?
The variable *i* is not given a value in *initiation_1*. That means that it gets its default value, which is the square root of ...

11 years ago | 0

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How to plot data with corresponding dates
The problem is that you are using linspace to produce equally separated dates rather than converting each of the actual dates. T...

11 years ago | 0

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Answered
Remove vertical stripping noise
You can smooth the image in the vertical direction, which reduces the amplitude of the circles but leaves the stripes. Then subt...

11 years ago | 2

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Answered
How to store number of images matrix and double values in cell or array?
Cell arrays could be used, but this looks like an ideal case for a struct array. See <http://www.mathworks.co.uk/help/matlab/str...

11 years ago | 0

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Answered
how i can implement lowpass filter on image using matlab
If you want to smooth with a Gaussian kernel, as already suggested, you might find gsmooth2, available <http://www.mathworks.co....

11 years ago | 1

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gender discrimination using image processing
A student once did a project with me on that. It was a long time ago but I think she had some success using facial skin texture ...

11 years ago | 0

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Problem with multiple if conditions....
The conditions are almost mutually exclusive and almost correct. To be absolutely right, you need the second inequality in condi...

11 years ago | 0

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Answered
What does this statement mean "Use a for loop to move x = 'a' half the distance to 'b' and do it 'n' times."
Suppose a is 3 and b is 7. Then the 'distance' from a to b is 4, half the distance is 2, and moving a that much towards b means ...

11 years ago | 0

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how can I make a mask that is like a circle??
Your specification isn't very precise, but the attached function may help.

11 years ago | 0

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Answered
adding matrices with different dimensions
Convert X to a column vector. Then bsxfun will do what you want. For example X = rand(1, 50); thita = rand(1, 180); ...

11 years ago | 0

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Answered
FFT in 3D matrix
I'm not quite sure what the second and third dimensions are, but assuming you want each column transformed on the time dimension...

11 years ago | 0

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How to find the variance of an image?
*var* requires a double or single argument. This will work: img = double(imread('eight.tif')); v = var(img); But note...

11 years ago | 1

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Answered
Best practice of for loops and vectorisation, also maybe cumprod.
prod(cellfun(@length, someArray))

11 years ago | 2

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Answered
set up a subkey for containers.map class
See <http://www.mathworks.co.uk/matlabcentral/fileexchange/33068-a-multidimensional-map-class my multidimensional map class>.

11 years ago | 2

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Answered
creating 3d array from images
B2 is the name of a variable, which has not been given a value. It appears that B1 was given a value in some code that isn't sho...

11 years ago | 0

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To ignore the data files with error and proceed in the code
Use try and catch. Something like for ... try gunzip ... catch me <test error, if it's significant...

11 years ago | 2

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Answered
matlab code to compute the DFT using just O(N (P + Q)) operations, instead of the O(N ^2 ) operations?
Just use the fft function. It's almost certainly as good as you'll get.

11 years ago | 0

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What do fspecial image filtering parameters mean?
The Gaussian filter does not have a sharp cut-off, but 2*pi*sigma is the wavelength at which the amplitude is multiplied by a fa...

11 years ago | 3

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Answered
Why does MATLAB even have single precision variables?
For most purposes, double precision is good because calculations are less likely to be affected by rounding errors (though it's ...

11 years ago | 2

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Very simple question about strings
"According to the numbers" is ambiguous. This sorts the strings in ascending order, making the digit in position 3 more signi...

11 years ago | 0

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Does Wake Forest University have a license with MATLAB
I'd start by asking <http://is.wfu.edu/ Wake Forest University Information Systems>.

11 years ago | 0

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How to locate the the position of a 3D subimage in larger image in Matlab?
Assuming you have used *load* to read the mat-files and the images are stored as X and Y, you can look for an exact match by che...

11 years ago | 1

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Reshaping X, Y, Z Data
X_New = X_New(:); Y_New = Y_New(:); Z_New_2 = Z_New_2(:); does what you asked - that is, it reshapes each of the arra...

11 years ago | 0

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Answered
hello all, am a beginner to image processing can anybody kindly explain what is the purpose of using the code from the line 44 to line 52 in harris corner detection pls help me out. am try to understand it form past 2 days . pls help me out.
Lines 44 and 45 implement the central definition of the Harris-Stephens corner measure. To undertand this, look preferably at th...

11 years ago | 1

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fortran77 to matlab convert
The code from "1 continue" to "go to 1" could be translated into a while loop, something like z1 = z + 1; % initial valu...

11 years ago | 1

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