How to specify the position of the displayed image?

In MATLAB R2023b, I used the function "imread" to import an image file named cat.png, later, I wanted to show this image, is there any way to display the image at the designated position on the coordinate axis? For example, I want the coordinates for the upper left corner(or center point) of the image to be (1,3).

Can someone help me? Thanks very much!

Answer 1

[Umar]

Hi @Marvellous,

You can place an image at a specific position on the axes in MATLAB R2023b using the image() function with 'XData'and 'YData'. This allows you to set either the upper-left corner or center point at coordinates like (1,3). For example:

   % Upper-left corner at (1,3)
   image('XData', [1, 1 + width - 1], 'YData', [3, 3 + height - 1], 'CData', img);

   % Center at (1,3)
    image('XData', [1 - width/2, 1 + width/2], 'YData', [3 - height/2, 3 + height/2], 
    'CData', img);

This method gives precise control over the image placement while preserving axes coordinates and aspect ratio.

Reference:

<https://www.mathworks.com/help/matlab/ref/image.html Matlab Image Documentation >

The script I provided demonstrates:

1. Image placement by upper-left corner at (1,3). 2. Image placement by center at (1,3). 3. An overlay figure showing both placements with annotations and a legend for visual verification.

Implementation

   %% MATLAB Script: Display Image at a Designated Position with Annotations
   % Author: Umar
   % Date: 2025-08-19
   % Purpose: Show image at specific coordinates and annotate positions
   % Image path: /MATLAB Drive/Cat.png

   %% Step 1: Read the image
   imagePath = '/MATLAB Drive/Cat.png';
   img = imread(imagePath);
   [height, width, ~] = size(img);

   %% Step 2: Display image using upper-left corner
   upperLeftX = 1;
   upperLeftY = 3;

   figure('Name','Image Placement - Upper Left Corner','Color','w');
   image([upperLeftX, upperLeftX + width - 1], [upperLeftY, upperLeftY + height 
   - 1], img);
   set(gca, 'YDir', 'normal');
   axis equal;
  axis on;
  grid on;
  xlabel('X-axis');
  ylabel('Y-axis');
  title('Image placed using upper-left corner at (1,3)');

   % Annotate upper-left corner
   text(upperLeftX, upperLeftY, sprintf('  Upper-left corner (%.1f, %.1f)',   
   upperLeftX, upperLeftY), ...
    'Color','red','FontWeight','bold','FontSize',12,'VerticalAlignment','top');

   %% Step 3: Display image using center point
   centerX = 1;
   centerY = 3;

figure('Name','Image Placement - Center Point','Color','w');
image([centerX - width/2, centerX + width/2], [centerY - height/2, centerY +    
height/2], img);
set(gca, 'YDir', 'normal');
axis equal;
axis on;
grid on;
xlabel('X-axis');
ylabel('Y-axis');
title('Image placed using center point at (1,3)');

% Annotate center point
text(centerX, centerY, sprintf('  Center (%.1f, %.1f)', centerX, centerY), ...
  'Color','blue','FontWeight','bold','FontSize',12,'VerticalAlignment','middle');

%% Step 4: Optional overlay with annotations
figure('Name','Overlay Example with Annotations','Color','w');
hold on;
% Upper-left corner
image([upperLeftX, upperLeftX + width - 1], [upperLeftY, upperLeftY + height - 
1], img);
text(upperLeftX, upperLeftY, sprintf('  Upper-left (%.1f, %.1f)', upperLeftX,   
upperLeftY), ...
  'Color','red','FontWeight','bold','FontSize',12,'VerticalAlignment','top');

% Center point with transparency
alpha = 0.5;
imgDouble = im2double(img);
image([centerX - width/2, centerX + width/2], [centerY - height/2, centerY +   
height/2], imgDouble, 'AlphaData', alpha);
text(centerX, centerY, sprintf('  Center (%.1f, %.1f)', centerX, centerY), ...
  'Color','blue','FontWeight','bold','FontSize',12,'VerticalAlignment','middle');

% Set axes properties
set(gca, 'YDir', 'normal');
axis equal;
axis on;
grid on;
xlabel('X-axis');
ylabel('Y-axis');
title('Overlay: Upper-left and Center Placement with Annotations');

% Create dummy plot handles for legend to avoid warnings
h1 = plot(nan, nan, 's', 'MarkerFaceColor','red','MarkerEdgeColor','red');
h2 = plot(nan, nan, 's', 'MarkerFaceColor','blue','MarkerEdgeColor','blue');
legend([h1, h2], {'Upper-left corner','Center point'});

hold off;

Please see attached.

[marvellous]

Thank you so much!

Answer 2

[DGM]

Both imshow() and image()/imagesc() allow you to specify the image extents in data coordinates directly.

% i assume you have something in the axes already
x = linspace(0,10,100);
y = 3*sin(x)+4;
plot(x,y); hold on
xlim([0 10])
ylim([0 8])

% and then you stick an image in it
% specify the extent of the image in data coordinates
% keep image aspect ratio in mind if necessary
inpict = imread('peppers.png');
imshow(inpict,'xdata',[1 6],'ydata',[3 7]) % corner at [1 3]

% undo the axis changes set by imshow()
axis on
grid on

●

[marvellous]

Thank you!