Applying a mask to 3D Data
19 次查看(过去 30 天)
显示 更早的评论
Hi everyone, I'm trying to generate a histogram of some data and I want to apply a 3D mask to the data. I have written as below, where fw is the data set that I'm trying to mask:
nbins = 20;
mask = find(mask);
selected_voxels = fw(mask); % ?
counts = histcounts(selected_voxels, nbins);
range = linspace(0, 1, nbins);
bar(range, counts)
I've chosen to use bar instead of MATLAB's histogram because I want to be able to place multiple bars beside one another and I've not found a way to do that using the basic histogram function. I used the find function since the values in my "mask" are not necessarily binary. However, a large number of voxels are being put in the highest bin.![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1340914/image.jpeg)
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1340914/image.jpeg)
The correct histogram should look as below, which I've plotted with Excel:
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1340919/image.jpeg)
Does anyone have any suggestions on how to fix my histogram? Notably, the highest bin should not have a peak and the number of voxels included in the histogram should be significantly lower. I have included both fw and the mask in .mat format.
Thank you,
Warren
0 个评论
回答(2 个)
Anton Kogios
2023-3-30
nbins = 20;
mask = mask==1;
selected_voxels = fw(mask); % ?
counts = histcounts(selected_voxels, nbins);
range = linspace(0, 1, nbins);
bar(range, counts)
Walter Roberson
2023-3-30
Your fw is 128 by 128 by 72 which is 1179648 elements.
Your mask is 186456 x 1. That is less than 1/6th of the size of fw.
Are you sure the mask is the right size?? MATLAB will effectively pad out the mask with false to be the same size as the array, but it seems very odd that you would pull out that particular part of the original data.
2 个评论
Walter Roberson
2023-3-31
编辑:Walter Roberson
2023-3-31
A lot of your selected voxels are exactly 1. As long as your mask is correct, there should be a large number in the last bin in the plot.
nbins = 20;
load fw
load mask_correct
selected_voxels = fw(logical(mask));
nnz(selected_voxels == 1)
counts = histcounts(selected_voxels, nbins);
range = linspace(0, 1, nbins);
bar(range, counts)
另请参阅
类别
在 Help Center 和 File Exchange 中查找有关 Histograms 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!