I need to divide my matlab output figure into pixels or grid of desired dimension.

How should it be done. should i save this output figure in another variable?

can "the game of life" coding approach be taken to divide the output figure into pixels.

(also thereafter change colour of the few selected pixels or grid and group them into different categories based on colour and make them move as pointer) i presently dont have image processing toolbox installed Suggest a solution

Answer 1

[KSSV]

clc; clear all ;
% make random data 
data = rand(1000,2) ;
% divide into grid
M = 5 ; N = 5 ;
x = linspace(0,1,M) ;
y = linspace(0,1,N) ;
[X,Y] = meshgrid(x,y) ;
Z = zeros(size(X)) ;
figure
plot(data(:,1),data(:,2),'.r')  ;
hold on
plot(X,Y,'k') ; plot(Y,X,'k')
%%Get points inside for each box 
P = cell(M,N) ;
for i = 1:N-1
    for j = 1:M-1
        A = [X(i,j) Y(i,j)] ;
        B = [X(i+1,j+1) Y(i+1,j+1)] ;
        idx = find(data(:,1) >= A(1) & data(:,1) <B(1)) ;
        idy = find(data(:,2) >= A(2) & data(:,2) <B(2)) ;
        id = intersect(idx,idy) ;
        P{i,j} = [data(id,1) data(id,2)] ;
        % plot points inside first box 
        plot(P{i,j}(:,1),P{i,j}(:,2),'O','color',rand(1,3))
    end
end

[h b]

{ % make random data

data = rand(1000,2) ;}

Here if i have a previously generated matlab output figure, i want to use this figure. how is it to be done.

[KSSV]

Won't you have a data? You got only figure?

Answer 2

[Walter Roberson]

Use mat2cell() to divide your image up into pieces.

It is not obvious to me that cellular automata has anything to do with your question.

If you want to move an image on the display, then image() or imshow() it and record the handle returned, and then to move it, change the handle XData and YData properties.

[Walter Roberson]

Setting the XData and YData would work if you were just moving the sections up/down/left/right, but in that simulation at http://kmarkow.github.io/roundabouts/ the sections need to curve as well.

To handle that, the easiest way might be to use one hgtransform for each section, and set the transform matrices as needed. You would need one hgtransform per section.

Another way of handling it would be to use one patch object for each section with the image displayed on the patch by using texture mapping, and instead of keeping an hgtransform for each section you would modify the patch vertex locations as you went. This would involve transform matrix calculations but not the overhead of an hgtransform for each object (but you would need to store the center coordinates and the orientation for each object.)

In theory you could also manage it all as one single patch object using texture mapping, with a whole bunch of faces that do not happen to connect together, with you modifying the vertex locations as you went. This would involve transform matrix calculations but not the overhead of an hgtransform for each object (but you would need to store the center coordinates and the orientation for each object.)

[h b]

will try as u suggested. thank you.

[h b]

how to display image after mat2cell operation. as imshow is not taking cell type as input

[Walter Roberson]

You have to imshow() or image() each of the cell entries, passing in XData and YData so that it displays in the proper location. Or, if you are intending to rotate like in the demonstration, you need to follow one of the other approaches I indicated (e.g. patch or hgtransform)

[h b]

Shall be grateful if u could also provide a sample code for the abv or a link for reference

[Walter Roberson]

Example without rotation

cam = imread('cameraman.tif');
subimages = mat2cell(cam, 16 * ones(1, 16), 16 * ones(1,16));
number_of_subimages = numel(subimages);

X = zeros(1, number_of_subimages);
Y = zeros(1, number_of_subimages);

for subidx = 1 : number_of_subimages
  imh(subidx) = image( subimages{subidx}, 'XData', X(subidx), 'YData', Y(subidx));
  hold on
end
hold off
axis([-100 300 -100 300])

%now move them

for movenum = 1 : 50
  for subidx = 1 : number_of_subimages
    X(subidx) = X(subidx) + randi([-32,32]);
    Y(subidx) = Y(subidx) + randi([-32,32]);
    set( imh(subidx), 'XData', X(subidx), 'YData', Y(subidx));
   end
   pause(1/4);
 end