I need to plot the Intensities in an image as a surface plot.

I need to plot the Intensities in an image as a surface plot. The surface plot must have the x values, y values and the intensity at every (x,y).

Answer 1

[Star Strider]

I am not certain what you mean by ‘intensity’, but this is one possibility for you to experiment with:

Pprs3 = imread('peppers.png');                  % Colour Image
Pprs1 = rgb2gray(Pprs3);                        % Grayscale Image
x = 0:size(Pprs1,2)-1;
y = 0:size(Pprs1,1)-1;
[X,Y] = meshgrid(x,y);                          % Coordinate Matrices (Not Necessary)

figure(1)
meshc(X, Y, Pprs1)                              % Mesh Plot
grid on
xlabel('X')
ylabel('Y')
zlabel('Intensity')
colormap(jet)                                   % Set ‘colormap’

The code first reads the image as RGB (3D) matrix of uint8 values, then converts it to a grayscale matrix of uint8 values. It then creates appropriate coordinate matrices (not necessary, but the plots look better with them), and plots them using the meshc function and the jet colormap. You can also use surf (or surfc) and other colormaps.

Experiment with this code and your image to get the result you want.

[Mohaliy2016]

It helps!

[Ayushman Sengar]

Not working for me just showing blanck screen

plz help

[Star Strider]

Ayushman Sengar —

It continues to work correctly for me (as posted) in R2020b.

The problem is not my posted code.

[Ayush singhal]

@Star Strider

hello, I need a small help regarding this.

I have two images like this.(attached). Now I would like to extract the object information from these two images. And show the final images with a surface plot.

could you give some hint about this?

Answer 2

[Krishnan Ramkumar]

Hi Aditya,

Generally 'surf' command is used to plot as a surface plot. Is there any issue that you faced while trying to use 'surf' command to plot the intensities in an image as a surface plot.

http://www.mathworks.com/help/matlab/ref/surf.html

Regards, Krishnan