How to Invert Pixels in a Specific Window of an Image Using MATLAB?

[Jordon]

Homework Statement

1.invert all pixel of a 20x20 window around I(X,Y)
2.set all pixel aroud the in the inverted images

Homework Equations

cant make work right way.
Please help me to solve problem.
Thanks,

The Attempt at a Solution

I=imread('test7.jpg'); % Load the image file and store it as the variable I.
x1=floor(rand*240+8);% generate random varible x1
y1=floor(rand*240+8);% generate random varible y1
for i=y1-7:y1+7
for j=x1-7:x1+7 % Show15x15 With (x,y) in the center
Ired(i,j)=I(i,j);
end
end
B=inv(Ired);
imshow(B); % show the modified image

 

[KataKoniK]

Hi there,

To invert all the pixels in the 20x20 window around I(X,Y), you can use the following code:

I = imread('test7.jpg'); % Load the image file and store it as the variable I.
x1 = floor(rand*240+8); % generate random variable x1
y1 = floor(rand*240+8); % generate random variable y1
for i = y1-7:y1+7
for j = x1-7:x1+7 % Show 15x15 with (x,y) in the center
I(i,j) = 255 - I(i,j); % invert the pixel value by subtracting it from 255 (assuming the image is grayscale)
end
end
imshow(I); % show the modified image

To set all the pixels around the inverted image, you can use the following code:

B = inv(I); % invert the entire image
for i = 1:size(B,1) % loop through the rows of the image
for j = 1:size(B,2) % loop through the columns of the image
if i >= y1-6 && i <= y1+6 && j >= x1-6 && j <= x1+6 % if the current pixel is within the 13x13 window around (x,y), set it to the corresponding pixel in the inverted image
I(i,j) = B(i,j);
end
end
end
imshow(I); % show the modified image

Hope this helps! Let me know if you have any further questions.

 

[Mene]

Hello,

It looks like you are attempting to invert the pixels of a 20x20 window around a specific point (x,y) in an image. Your code appears to be generating a random point (x1,y1) and then selecting a 15x15 window centered around that point. However, you are not actually inverting the pixels in this window. Instead, you are simply copying the original image into a new variable (Ired).

To invert the pixels, you will need to loop through each pixel in the window and calculate its inverse. This can be done using the 'inv' function in Matlab. Additionally, you will need to set the pixels around the inverted window to the inverted values. This can be done by using the same loop structure and setting the appropriate pixels to the inverted values.

I would suggest breaking down the problem into smaller steps and testing each step individually to make sure it is working correctly. Also, make sure to check the dimensions of your variables and make sure they match the desired window size. Good luck!