i am applying Arnold's transform on the pixels

1 visualización (últimos 30 días)
sadiqa ilyas
sadiqa ilyas el 13 de Ag. de 2019
Comentada: sadiqa ilyas el 13 de Ag. de 2019
Hi, I am writing a code for the following transformation
T[x;y]=[x+y:x+2y]
the code is
n=256;
I=imread('fruit1.bmp');
Red=I(:,:,1);
Green=I(:,:,2);
Blue=I(:,:,3);
x(1)=Red(1);
y(1)=Green(1);
for i=1:15
x(i+1)=mod(x(i)+y(i),n)
y(i+1)=mod(x(i)+2*y(i),n)
end
[x; y]
but I am getting the following results,which is definitley wrong.Can any one tells me why I am getting 255.
227 255 255 255 255 255 255 255 255 255 255 255 255 255 255
213 255 255 255 255 255 255 255 255 255 255 255 255 255 255
Column 16
255

Respuesta aceptada

Guillaume
Guillaume el 13 de Ag. de 2019
Your image is of type 'uint8'. This means the range of intensities is between 0 and 255 (included). If you sum two uint8 and the result is greater than 255, the sum gets clamped to 255. If you subtract two uint8 and the result is less than 0, you'll get 0.
The simplest way to fix that problem is to convert your original image to double:
I = double(imread('fruit1.bmp')); %don't use im2double if you want the intensities to stay as 0-255
I have no idea what this notation mean:
T[x;y]=[x+y:x+2y]
and I've never heard of Arnold's transform. I assume it's this, in which case your notation is missing the mod.
But if that's what you're trying to implement, then your code has many problems:
  • Your current code depends on the red and green intensity of the 1st pixel only, since the only thing that influences the result of the loop is the value of x(1) and y(1) before the loop. As a transform, that's hardly useful.
  • The cat transformation described in the wikipedia article I've linked, alters the location of the pixels (jhence the use of x, y) not the colour of the pixels (what you're currently doing).
  1 comentario
sadiqa ilyas
sadiqa ilyas el 13 de Ag. de 2019
Thanks. your suggestion to use double in the oriinal image is useful. I am trying to apply Arnold's cat transform and for this I trying to write my own code to learn Matlab.

Iniciar sesión para comentar.

Más respuestas (0)

Categorías

Más información sobre Convert Image Type en Help Center y File Exchange.

Etiquetas

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by