Question

Calculate the mean of nonzero pixels and set a threshold

I previously asked how to calculate the mean of nonzero pixels using my binary mask. The way I did that was m = mean(volume(ma...

1 month ago | 0 answers | 0

Question

Calculate the mean of nonzero pixels

I have a 3D volume and a 3D binary mask. I want to calculate the mean of the pixels which correspond to the regions where the ma...

2 months ago | 2 answers | 0

Question

Calculate the mean of 4D image using a 3D mask

Hi there, I have 4D data with dimensions [308,384,26,31]=[x,y,z,time]. I also have a binary 3D mask with dimensions [308, 384,...

2 months ago | 0 answers | 0

Question

Masking data of 4D images

Hi there, I have a 3D binary mask and I would like to mask my 4D data. So basically I would like to keep the information of my...

2 months ago | 1 answer | 0

Question

Cannot load .nii.gz files with MATLAB 2017b

Hi there, I have a problem loading Nifti gz files (.nii.gz) with MATLAB 2017b. I am loading my .nii.gz using the below: loa...

2 months ago | 0 answers | 0

Question

Question about imgaussfilt3

I used the imgaussfilt3 to smooth my 3D images. When you set sigma=1.0 which is the standard deviation of the Gaussian smoothin...

4 months ago | 1 answer | 0

Question

3D Gaussian filterning affects resolution of the images?

I have used the imgaussfilt3 function to smooth my 3G images. I used the default settings where the 3D Gaussian kernel has stand...

5 months ago | 0 answers | 0

Question

Gaussian smoothing filtering of 4D data

Hi, I have 4D MRI data (Magnetic Resonace Imaging). Where dimensions are: x-, y-, z- dimension and time. I would like to sm...

6 months ago | 2 answers | 0

Question

Display data points in boxplots

I am using the boxplot function to create boxplots of my data. But I would also like to plot my data on top of the boxplots. Ca...

7 months ago | 1 answer | 0

Question

Plot histograms of two samples as plots

I would like to plot the histograms of two samples as a line plot. I've been using the histograms functions but this is not wh...

7 months ago | 1 answer | 0

Question

Load NifTI zip files in Matlab R2017b

I'm trying to load NifTI zip files in Matab R2017b with the function load_untouch_nii but I keep getting the following error: ...

8 months ago | 0 answers | 0

Question

How is the residual in lsqnonlin calculated?

Does anyone know how's the residual being calcualted in lsqnonlin function? I am interested to know the formula. Is it : res ...

8 months ago | 0 answers | 0

Question

Identify the nonzero pixels

I have a stack of 3D volumes, i.e. 4D with dimensions [156, 192, 26, 41]. I have also a 3D binary mask with dimensions [152, 19...

8 months ago | 2 answers | 0

Question

How to set a threshold in data

I have a 3D images stored in a matrix A. Some pixels are outliers and I want to put a threshold. When the value at particular...

9 months ago | 1 answer | 0

Question

Covariance matrix not always positive define

I have used the cov Matlab function to calculate the covariance matrix. I calculate the covariance matrix inside a loop and t...

9 months ago | 0 answers | 0

Question

Polyfit function - NaN

I have the age and blood measurement of some data. For some people the age is missing and I marked them as NaNs. When I used t...

9 months ago | 1 answer | 0

Question

How to loop over a series of files

I have 10 datasets named data1, data2,data3,...,data10 with dimensions [150,120, 25, 5]. I want to create a big matrix and put a...

9 months ago | 1 answer | 0

Question

Improving the fitting of data

I have a small group of people (n=15). For each person I have the age and a blood measurement. The relationship between the age ...

9 months ago | 2 answers | 0

Question

Covert a Binary Image

Hi, I have a 4D binary image filled with 0 and 4. Voxels with 0 appear black and voxels with 4 appear white. How can I make ...

10 months ago | 0 answers | 0

Question

Access different elements of matrix

I have a 4D matrix with dimensions A = [100,100,25, 9]. I want to create another matrix including only the 2,3,4,5 and 7th elem...

10 months ago | 1 answer | 0

Question

Can you use Batched partitioned nonlinear least squares to fit 5 parameters?

Hi, I've seen people using the batched partitioned nonlinear least squares to solve nonlinear problems of two unknown parame...

1 year ago | 1 answer | 0

Question

lsqnonlin - how to return the best fit

I am fitting a function nonlinearly using the lsqnonlin function. I have used the [x, res] to return the parameters (i.e. x) a...

1 year ago | 1 answer | 0