matlab commands

Mean

A=[1 2 3 4;5 6 7 8];

i)                    mean (A)=mean(A,1)=[3,4,5,6]; %column-wise mean

Explanation:

1 2 3 4
5 6 7 8
---------
3 4 5 6

ii)                   mean(A,2)= [2.5,4.5];

1 2 3 4-----(1+2+3+4)/4 = 10/4 =2.5
5 6 7 8-----(5+6+7+8)/4 = 26/4 =4.5

Size

size(A,2) =  4 %number of columns

size(A,1) = 2%number of rows

We Normalize images to reduce the error due to lighting conditions

A=
1 2 3 4
5 6 7 8

A'=
1 5
2 6
3 7
4 8

temp=A'(:);
=
1
2
3
4
5
6
7
8

If A=
1 2
3 4
-----
2 3

here n-1= 2-1=1;

std(A)=

[√ (1-2)²+(3-2)²/(2-1)     √ (2-3)²+(4-3)² /(2-1) ]     =[ √2/1    √2/1] =  [√2    √2]= [1.414   1.414];

Sum(A,1)=sum(A)=[4 6]

Sum(A,2)=[3 7]%row wise sum

A(:,1).^2

=

1

9

A= 1       B= 4
   2          5

   3          6

A’*B =32

[1 2 3]*  4           4+

          5  =        10

          6           18

                    -------

                      32     

 

img=uint8(image);   %converts to unsigned 8-bit integer. Values range from 0 to 255

Normalize cheyataniki  its own mean tho minus chestamu