Image matrix dimensions flipped compared to original image

img1 = rgb2gray(imread('Image1.png'));

size(img1)

ans =

384 512

When I apply this command to load the image the matrix 384x512. However, the original png image has 512x384 pixels. What am I missing here that the image matrix in MATLAB looked flipped. I was expecting MATLAB to create a 512x384 matrix.

Answer 1

[Ameer Hamza]

Commonly image resolution is expressed as width x height. However, in MATLAB the size() returns "number of rows (height)" x "number of columns (width)". However, it should not look flipped due to this. imshow() should show the same image as shown outside MATLAB.

[Punnag Chatterjee]

Yes, when I use imshow it does show the image correctly, the problem occurs when I am indexing the individual matrix elements for some image operations.

[Bjorn Gustavsson]

Then you'll have to "learn to accept" the matlab-indexing-notation/convention:

I_xy = Img(row_idx_y,col_idx_x);