## Looping through a matrix with unknown dimensions

### Bubbles Lol (view profile)

on 9 Sep 2019
Latest activity Commented on by Rena Berman

### Rena Berman (view profile)

on 19 Sep 2019 at 15:49
function [r,g,b] = Distant_Pixel(n)
pixels= gallery('integerdata',54,[1,n,3],42);
[R,G,B] = Median_Pixel(n);
r = Pixel_Distance([R,G,B],[pixels(1,1),pixels(1,1,2),pixels(1,1,3)])
g = Pixel_Distance([R,G,B],[pixels(1,2),pixels(1,2,2),pixels(1,2,3)])
b = Pixel_Distance([R,G,B],[pixels(1,3),pixels(1,3,2),pixels(1,3,3)])
end
Median_Pixel and Pixel_Distance are functions.
Since n will change depending on input. How do I fix the pixels matrix so that it works with any input of n
[pixels(1,1),pixels(1,1,2),pixels(1,1,3)] -- ?

Rik

### Rik (view profile)

on 11 Sep 2019
It is considered extremely rude to edit away your question. You're getting free help from strangers, the least you can do is to leave it up for potential future people with similar issues.
John D'Errico

### John D'Errico (view profile)

on 11 Sep 2019
You insult the people who tried to help you by editting away your question, and you make it useless for anyone else to ever learn from the responses. We have asked the site admins to restore it.
Rena Berman

### Rena Berman (view profile)

on 19 Sep 2019 at 15:49

### Walter Roberson (view profile)

on 9 Sep 2019

function [r,g,b] = Distant_Pixel(n)
pixels= gallery('integerdata',54,[1,n,3],42);
[R,G,B] = Median_Pixel(n);
r = []; g = []; b = [];
if n >= 1
r = Pixel_Distance([R,G,B],[pixels(1,1),pixels(1,1,2),pixels(1,1,3)]);
end
if n >= 2
g = Pixel_Distance([R,G,B],[pixels(1,2),pixels(1,2,2),pixels(1,2,3)]);
end
if n >= 3
b = Pixel_Distance([R,G,B],[pixels(1,3),pixels(1,3,2),pixels(1,3,3)])
end
end

Bubbles Lol

### Bubbles Lol (view profile)

on 9 Sep 2019
The input of the function is a 1*n*3 array. Containing rgb values. I want to find the most distant rgb pixel values from those that are provided in the array. So how would I do this? and n can be any number. Thanks
Walter Roberson

### Walter Roberson (view profile)

on 9 Sep 2019
We do not know what your function Pixel_Distance does.
It is not clear what the most "distance" rgb values means in this situation, since you appear to be talking about 3 different values
Given a set of pixel values, you can take the mean or median . Now for any one median component (say the G), check to see whether the component is above or below 1/2 of the maximum possible value (e.g., 128 if the values are uint8). If the component is below 1/2 of the maximum possible, then the most distant value is the maximum possible value (e.g., 255); if the component is above 1/2 of the maximum possible, then the most distant value is the minimum possible value (e.g., 0)