Hi! I have a 3d matrix of 0's and 1's. I would like to plot it with scatter3 with 0's showing up black and 1's showing up white. Is that possible?
Thank you, Inês
MATLAB: How to give diferent colours to diferent values in a matrix
binary_matrixscatter3
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I don't have time to give full code, but the first option gives you what you need - i.e a single scatter3 instruction, not a massive nested loop. The 5th argument is an n*3 array of colours where n must be the same size as the number of points in your col, row, zz arrays.
Here is some example code you can hopefully adapt to your case:
e.g.
x = rand( 10,1);y = rand( 10,1);z = x.^2 + y.^2;c = rand( 10, 3 ); % 10 random colours
figure; scatter3( x, y, z, [], c, 'filled' )will give you a simple scatter plot with different coloured points.
Now all you need to do is, instead of creating 10 random colours as I did there, create a colourmap of the required size e.g.
cmap = [ ones( 256, 1 ), linspace( 0, 1, 256 )', zeros( 256, 1 ) ];Now you have 256 colours between red and yellow. Your data needs to be binned to index into this colourmap though. This is doable by e.g.
a = rand( 1, 100000 ); % Lots of random continuous data
idx = discretize( a, 256 ); % discretise your data into 256 bins;
(In my original comment above I was going to suggest discretize, but missed that it had an option to supply number of bins rather than explicit edges so this is easier than histcounts which doesn't actually bin your data, it just gives the histogram counts as totals).
Then you have all your data in 256 bins and can use those indices into your colourmap.
c = cmap( idx, : );should do this for you, and then you can use this as 'c' in my above scatter3 line instead of random colours.
Oh yeah, It's crystal clear now!
So, for instance the color you want to pick is black and you just want to define it.
I took a look at your question again. ginput gives you the x and y in respect to x and y axes, for images, ginput returns the pixel number (pixel 0 0 is on the top and left of the image) so it does not provide any color info on it's own.
You can use the result of the ginput to get the color though. Depending on the type of the image you're loading to MATLAB, you'll have different data types, lets say you loaded a colored image of type PNG. then you'll have a (Xpixel x Ypixelcdata x 3) cdata (color data) matrix. 3rd dimension is 3, representing the red, green and blue and they're uint8 type, means the're in between 0 to 255.
So let's say you want to red color. then
myPic(1,1,1:3) = [255,0,0]myPic(1,2,1:3) = [0,255,0]myPic(1,3,1:3) = [0,0,255]to define a color for your purpose I believe you've to do it as such
color = [255,100,44] % whatever color it is!
Just combine the three colors with with different amounts and produce what ever color you want.
If you want to cheat from the image, just use ginput to get the x and y coordinates of the desired pixel then in the cdata matrix or whatever matrix you named it, I named it myPic, get the color values to understand their mixture.
mypic(x,y,:)Hope this can answer your question, sorry I got back to you a bit late.
Good Luck!
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