How to select the range of data based on threshold range of our own choice?
3 views (last 30 days)
Show older comments
Amjad Iqbal
on 20 Sep 2022
Commented: Amjad Iqbal
on 20 Sep 2022
Dear MATLAB experts,
I want to use only the points corresponding to relatively high amplitudes? (e.g., try -10 to 0 dB or -20 to -10 dB or -30 to -20 on the normalized plots).
In attached imaging data output which veries from -45 to 0 dB.
I want to make 3 classes and plot data in with 3 classes and 3 colors.
.
I lookforward to receive your suggestions. I tried an approach but it gives logical output which is not suitable for my case.
Tahnk you!
2 Comments
Image Analyst
on 20 Sep 2022
You can adapt the colormap to have only 3 colors. Please attach your original image varible in a .mat file if you want anybody to try anything. What do you want to be the color if the value is outside your ranges? Why do your three ranges (-10 to 0 dB, or -20 to 10 dB, or -30 to -10) overlap? For example a -15 : which class should it be in the second or the third???
Accepted Answer
Image Analyst
on 20 Sep 2022
Try this:
load('output_classes.mat'); % data
intensity = 20*log10(abs(S_VH)/max(max(abs(S_VH))));
imagesc(x_vect, y_vect, intensity,[-45 0]);
axis('equal');
axis('tight');
title('Output');
cmap = [0,0,0;
1,0,0;
0,1,0;
0,0,1
]
colormap(cmap);
colorbar;
caxis([-40, 0]);
set(gca,'FontSize',14)
grid;
More Answers (0)
See Also
Categories
Find more on National Instruments Frame Grabbers in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!