How to move an image inside a computational grid?

Hello everyone,

I wish to move an image along a particular direction inside a bigger computational grid (the intensity values of the bigger computational grid is zero except of image region). Size of computational grid is ((X, Y) = (256 , 128)) and an image is place inside this computational grid at (216:266, 44:47).

So how can move the image along the x-direction (e.g. 216 --> 100 with step size , so the position of the image will become (116:166, 44:47)) place inside the bigger computational.

Suggestion/Help please.

Thank you.

Answer 1

[darova]

Try this

clc,clear

[x,y] = meshgrid(0:10);         % main grid
[x1,y1] = meshgrid([4 6]);      % small rectangle
surf(x,y,x*0,'facecolor','b');  
dx = rand(1,10);
dy = rand(1,10);
h = surface(x1,y1,x1*0+0.1,'facecolor','r');
for i = 1:length(dx)
    set(h,'xdata',x1)
    set(h,'ydata',y1)
    pause(0.5)
    x1 = x1 + dx(i);
    y1 = y1 + dy(i);    
end

[S]

Hi Darova,

Thank you Thank you very much .. Now I do have an idea how I should proceed for my problem .. Thank you very much buddy ..

[S]

Hey Darova ,

I have one more question as I am not clear with the idea behind the steps "h = surface(x1, y1, x1*0+0.1)" ..

Could you please help me understand (x1*0 + 0.1) ??

[darova]

• Could you please help me understand (x1*0 + 0.1) ??

Its Z coordinate. BIg mesh is Z=0, so the small rectangle should be on top, i made z=0.1

[S]

Thank you.

Answer 2

[KSSV]

I = imread('peppers.png') ; 

[X,Y] = meshgrid(1:100,1:100) ; 


plot(X,Y,'r') ;
hold on
plot(X',Y','r') ;
image([20 50],[20 50],I)
set(gca, 'YDir','reverse')

[S]

Thank you very much for the help. But the my situation is different then what you have considered.

Its like I want to move a set of point (about 20-25) that is inside the red box (which i call as an image) and while we move the in upward direction I dont wish to change the intensity value .. just the position of the points along the x-axis.