ginput, several curves in one plot

Hi

So i have a 'ginput' command that produces a spectrum of a spot in an image. How do i plot all the points I select in the same graph, so that i can compare multiple spectra readily, please?

Thanks for the help

Answer 1

[Image Analyst]

Use plot and hold:

plot(spectralCurve1, '-', 'LineWidth', 2);
hold on;
plot(spectralCurve2, '-', 'LineWidth', 2);
plot(spectralCurve3, '-', 'LineWidth', 2);

etc.

[kenoz]

Hi, thanks for the response. I tried this but that didn't work.

So this is what i am working with:

figure(1);

imshow(rgbImage);

disp ('Pick the first suspected color');

[a, b] = ginput;

figure(2)

plotc (wavelengths, squeeze(imageStack(ceil(a),ceil(b),:)/1)); xlabel ('Wavelength/nm'); ylabel ('Reflectance');

I would like to repeatedly go back to figure (1) to pick different spots on the rgb(Image), but all the spectra should be plotted in the same graph (figure (2)).

I hope this makes it easier to help out.

Thanks

[Image Analyst]

No it didn't make it easier. For one, put all that squeeze stuff before the plot to make a single vector, and put the xlabel and ylabel on separate lines.

Then, I see no reason why you can't, in a loop, just put hold on, and plot your other curves that you got from other clicks. You didn't explain why it did not work. I'd do something like

for k = 1 : numCurves
    figure(1) % Move to the image figure.
    uiwait(helpdlg('Click on a point'));
    (x, y) = ginput()
    thisSpectrum = ......squeeze(.......
    figure(2) % Move over to the plotting figure.
    plot(thisSpectrum.......
    hold on;
end
grid on;

Also, your badly-named a and b caused you to flip the rows and columns. a is x which is columns, so it comes second. In other words, it's not imageStack(ceil(a),ceil(b),:), it should really be imageStack(ceil(b),ceil(a),:). An all too common beginner's mistake, so you're not the only one.

[kenoz]

Thank you very much.

It worked.