I have made a matrix containing 13 different vectors with ~300K+ rows. I have visualized the matrix by transposing it and using the imagesc function to see the distribution of colors. All vectors have been resampled, processed and normalized between 0 & 1 individually.
The imagesc plot gives me this result (fig 1):
But, when I use the axis functionality to add x & y limits, I get this:
How do I maintain the imagesc plot while being able to add custom ticks and labels to the X & y axis? The x axis represents time, while the y axis will get its own labels with sensor names.
You redefine limits from 0 to 30 on the x-axis while the initial xlimits goes up to 3e5. Same issue with the y-axis
Here's how to redefine the Y-axis to put sensor names:
C = [0 2 4 6 9 ; 8 10 12 44 14; 16 48 10 32 23];
image(C)
% Get axis handle
ax = gca;
% Set where ticks will be
ax.YTick = [1 2 3];
% Set TickLabels;
ax.YTickLabel = {'S1','S2','S3'};
Figure out the ax.YTick where you want the labels to appear.
If you want the x-axis to go from 0 to 30, divide the x component of all vectors by 1e4 before plotting. Alternatively, you can add the line:
ax.XTickLabel = ax.XTick/1e4;
Related
I have a discrete signal x of length N traced in MATLAB using the command
stem(abs(x)); axis([0 N+6 0 4]);
The resulted figure is shown below:
My question I need only some values corresponding for example to index [7 10 11 12 15 18 48 50 52 60] to be colored with different color , let's say with red.
How can I do that into my figure ?
Using Multiple Plots by hold on and Matrix Indexing
You could possibly and alternatively place a plot on top of plot by using hold on. This does require an adjustment where you need a vector in this case Sample and Indices which specify the sample number/data point index. You can also use matrix indexing to get the amplitude/data points corresponding to the key point, Indicies.
%Vector relating to the sample/data point number%
Sample = linspace(1,70,70);
%Random test data%
X = randi([0,2],1,70);
stem(Sample,X);
hold on
%Key indices to change colour%
Key_Indices = [7 10 11 12 15 18 48 50 52 60];
%Matrix indexing to get values/amplitudes corresponding to key indices%
X_Prime = X(Key_Indices);
stem(Key_Indices,X_Prime,'r');
axis([0 70 0 3]);
hold off
Ran using MATLAB R2019b
This code makes just the circles red and not the stems
plot with selected red circles
%Vector relating to the sample/data point number
Sample = linspace(1,70,70);
%Random test data
X = randi([0,2],1,70);
stem(Sample,X);
%Key indices to change color
Key_Indices = [7 10 11 12 15 18 48 50 52 60];
line(Sample(Key_Indices), X(Key_Indices), 'linestyle', 'none', 'marker', 'o', 'color', 'r')
axis([0 70 0 3])
grid on
I'm trying to label my XRD data which have peaks, and I want to label it from my array of data:
peak label
ab
ac
ad
cb
bb
ba
See picture below
I also want those labels to be vertically aligned on the top of the peaks.
I tried the findpeaks function but it doesn't work.
Try this (but you need to have a Signal Processing Toobox):
x = [1 2 3 4 5 6 7 8 9]
y = [1 4 2 7 3 9 5 10 2]
[peak, peakId] = findpeaks(y); %find peaks in your serie
figure(1)
plot(x, y)
lbalph=('a':'z').'
lb=strcat(Alphabet(1),lbalph(1:length(peak))) %Create a label matrix
lb = num2cell(lb,2) % Convert to cell array
lbid = 1:length(lb)
text(x(peakId), peak, lb(lbid),'Rotation',90) % label the peak with your lb matrix
As you have the index peaks, you can labeled as you want.
Using plot3 I have created a multiple discrete line 3d plot. How can I fill the 3d surface these lines create (basically join the lines with a surface)?
Using fill3 can help.
x = [0 0 5 5 0];
y = [5 5 0 0 5];
z = [0 5 5 0 0];
subplot(1,2,1)
plot3(x,y,z,'LineWidth',5);
grid on
subplot(1,2,2)
fill3(x,y,z,'y')
grid on
I want to visualize my matrix with the computed mean of that matrix.
And I want to plot that points and the mean at the same window.
here is my Matrix and the Mean
Input=4 1 1
3 9 0
2 5 5]
Average=mean(Input
How to plot it??
To plot figure I using this command:
plot(InputMatrix(:,:,:),Average'*');
There are 9 points, but I just need 3 points from matrix and 1 point of the mean...
1st point from -->4 3 2
2nd point from -->1 9 0
3rd point from -->1 0 5
the 4th point is -->the mean / average
You can use plot3:
plot3(Input(1,:),Input(2,:),Input(3,:),'o') %// plot each point (in 3D)
hold on
m = mean(Input,2); %// compute mean of all points
plot3(m(1),m(2),m(3),'*') %// plot the mean
I have an intensity/greyscale image, and I have chosen a pixel inside this image. I want to send vectors starting from this pixel in all directions/angles, and I want to sum all the intensities of the pixels touching one vector, for all vectors.
After this step I would like to plot a histogram with the intensities on one axis and the angle on the other axis. I think I can do this last step on my own, but I don't know how to create these vectors inside my greyscale image and how to get the coordinates of the pixels a vector touches.
I previously did this in C++, which required a lot of code. I am sure this can be done with less effort in MATLAB, but I am quite new to MATLAB, so any help would be appreciated, since I haven't found anything helpful in the documentation.
It might not be the best way to solve it, but you can do it using a bit of algebra, heres how...
We know the Point-Slope formula of a line passing through point (a,b) with angle theta is:
y = tan(theta) * (x-a) + b
Therefore a simple idea is to compute the intersection of this line with y=const for all const, and read the intensity values at the intersection. You would repeat this for all angles...
A sample code to illustrate the concept:
%% input
point = [128 128]; % pixel location
I = imread('cameraman.tif'); % sample grayscale image
%% calculations
[r c] = size(I);
angles = linspace(0, 2*pi, 4) + rand;
angles(end) = [];
clr = lines( length(angles) ); % get some colors
figure(1), imshow(I), hold on
figure(2), hold on
for i=1:length(angles)
% line equation
f = #(x) tan(angles(i))*(x-point(1)) + point(2);
% get intensities along line
x = 1:c;
y = round(f(x));
idx = ( y<1 | y>r ); % indices of outside intersections
vals = diag(I(x(~idx), y(~idx)));
figure(1), plot(x, y, 'Color', clr(i,:)) % plot line
figure(2), plot(vals, 'Color', clr(i,:)) % plot profile
end
hold off
This example will be similar to Amro's, but it is a slightly different implementation that should work for an arbitrary coordinate system assigned to the image...
Let's assume that you have matrices of regularly-spaced x and y coordinates that are the same size as your image, such that the coordinates of pixel (i,j) are given by (x(i,j),y(i,j)). As an example, I'll create a sample 5-by-5 set of integer coordinates using MESHGRID:
>> [xGrid,yGrid] = meshgrid(1:5)
xGrid =
1 2 3 4 5
1 2 3 4 5
1 2 3 4 5
1 2 3 4 5
1 2 3 4 5
yGrid =
1 1 1 1 1
2 2 2 2 2
3 3 3 3 3
4 4 4 4 4
5 5 5 5 5
Next we can define a line y = m*(x - a) + b passing through the coordinate system by selecting some values for the constants and computing y using the x coordinates of the grid:
>> a = 0;
>> b = 1;
>> m = rand
m =
0.5469
>> y = m.*(xGrid(1,:)-a)+b
y =
1.5469 2.0938 2.6406 3.1875 3.7344
Finally, we find the y points in the grid that differ from the points computed above by less than the grid size:
>> index = abs(yGrid-repmat(y,size(yGrid,1),1)) <= yGrid(2,1)-yGrid(1,1)
index =
1 0 0 0 0
1 1 1 0 0
0 1 1 1 1
0 0 0 1 1
0 0 0 0 0
and use this index matrix to get the x and y coordinates for the pixels crossed by the line:
>> xCrossed = xGrid(index);
>> yCrossed = yGrid(index);