How to get Pixels intensities on a circles with radii R for an image with selective angles?

How to get Pixels intensities on a circles with radii R for an image with selective angles?

[KSSV]

Any pictorial example?

[Rashmi.D Jeya kumar]

    Angles = [0, 45, 90, 135, 180, 225, 270, 315, 360] ;   % location in degrees 
    % In polar coordinates 
    R=3;
    iwant = [repmat(R,1, length(Angles)); Angles*pi/180]
    % In cartesian coordinates 
    x = R*cos(Angles*pi/180) ;
    y = R*cos(Angles*pi/180) ;

sir here where I insert my input image?

[KSSV]

You have these location on circle...do you have any other image, for which you want to extract the pixel values?

[Rashmi.D Jeya kumar]

Answer 1

[Image Analyst]

Try this:

for k = 1 : length(x)
    row = round(y(k)); % Round to nearest integer.
    col = round(x(k)); % Round to nearest integer.
    pixelValues(k) = grayImage(row, col);
end

[Rashmi.D Jeya kumar]

where I give radius sir?

[Image Analyst]

You assigned it. You said R was = 3. Remember your code that you posted:

Angles = [0, 45, 90, 135, 180, 225, 270, 315, 360] ;   % location in degrees 
% In polar coordinates 
R=3;
iwant = [repmat(R,1, length(Angles)); Angles*pi/180]
% In cartesian coordinates 
x = R*cos(Angles*pi/180) ;
y = R*cos(Angles*pi/180) ;

See where it assigns the radius to 3? You did that. By the way, you can use cosd instead of cos, and sind instead of cos (which you wrongly used):

x = R * cosd(Angles);  % The "d" versions take angles in degrees, not radians.
y = R * sind(Angles);

[Rashmi.D Jeya kumar]

ok sir i got error

[Rashmi.D Jeya kumar]

geting single value

[Image Analyst]

Well of course you were supposed to realize that you need to replace the image variable, grayImage, with the actual name of the variable in your program.

Maybe you didn't call it something useful and descriptive like grayImage. Maybe you called it I or X or something. Tell me exactly what you called your image variable when you called imread() (or somehow otherwise created it).

[Rashmi.D Jeya kumar]

M=imread('index.jpg');
grayImage=rgb2gray(M);

[Image Analyst]

There is no zeroth row or zeroth column. You need to have rows and columns start at 1.

[Rashmi.D Jeya kumar]

clc;
clear all;
close all;
M= imread('alu foil.jpg') ;
I=rgb2gray(M);
%I=mat2gray(N);
I1=imgaussfilt(I,2);
I2=imgaussfilt(I1,2);
I3=imgaussfilt(I2,2);
subplot(2,2,1);imshow(I);title('orginal image', 'FontSize', 10);
subplot(2,2,2);
imshow(I1);
title('1st Blur', 'FontSize', 10);
subplot(2,2,3);
imshow(I2);
title('2nd Blur', 'FontSize', 10);
subplot(2,2,4);
imshow(I3);
title('3rd Blur', 'FontSize', 10);

[ro co]=size(I);
for r = 2 : ro - 1   
  for c = 2 : co - 1    
    centerPixel = I(ro, co);
    end
end
meanval = mean2(I);
ELBP_CI = double((centerPixel-meanval) >= 0);

P neighbors of a central pixel are evenly distributed on a circle with radius R and have intensities denoted as gp;By comparing neighboring pixels with their average value denoted as uR

spatial relationships of pixels on two circles with radius R,R'

R= 40;
xc=size(I)/2+.5;
yc=size(I)/2+.5;
Angles = [0, 45, 90, 135, 180, 225, 270, 315, 360] ;
x = xc(1)+R*cos(Angles*pi/180) ;
y = yc(1)+R*sin(Angles*pi/180) ;
for k = 1 : length(x)
    row = round(y(k)); 
    col = round(x(k));
    pixelvalue(k) = I(row, col);
end
 neighb_pixelsaverage=(pixelvalue(1)/9)+(pixelvalue(2)/9)+(pixelvalue(3)/9)+(pixelvalue(4)/9)+(pixelvalue(5)/9)+(pixelvalue(6)/9)+(pixelvalue(7)/9)+(pixelvalue(8)/9)+(pixelvalue(9)/9);
 ELBPNI=0;
for i=1 : length(pixelvalue)
    L=pixelvalue(i)-neighb_pixelsaverage;
    if(L>=0)
     M=1;
    end
    if (L<0)
     M=0;
    end
    ELBPNI(i)=M*(2^i);
    ELBPNI=ELBPNI+ELBPNI(i);
end
ELBP_NI=ELBPNI;
R=70;

x = xc(1)+R*cos(Angles*pi/180) ;
y = yc(1)+R*sin(Angles*pi/180) ;

for k = 1 : length(x)
    row = round(y(k));
    col = round(x(k));
    pixelvalue1(k) = I(row, col);
end

   neighb_pixelsaverage1=(pixelvalue1(1)/9)+(pixelvalue1(2)/9)+(pixelvalue1(3)/9)+(pixelvalue1(4)/9)+(pixelvalue1(5)/9)+(pixelvalue1(6)/9)+(pixelvalue1(7)/9)+(pixelvalue1(8)/9)+(pixelvalue1(9)/9);
   ELBPNI=0;
  for i=1 : length(pixelvalue)
      L=pixelvalue1(i)-neighb_pixelsaverage1;
      if(L>=0)
          M=1;
     if(L<0)
             M=0;
         end
       ELBPNI1(i)=M*(2^i);
       ELBPNI1=ELBPNI1+ELBPNI1(i);
      end
  end
  ELBP_NI1=ELBPNI1;
  for i=1 : length(pixelvalue)
      L=pixelvalue(i)-pixelvalue1(i);
      if(L>=0)
          M=1;
     if(L<0)
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 M=0;
         end
       ELBPRD(i)=M*(2^i);
       ELBPRD=ELBPRD+ELBPRD(i);
      end
  end
  ELBP_RD=ELBPRD;

I didnt complete entire code.up to this the code is right or any modifications?

clc;
clear all;
close all;
M= imread('alu foil.jpg') ;
I=rgb2gray(M);
%I=mat2gray(N);
I1=imgaussfilt(I,2);
I2=imgaussfilt(I1,2);
I3=imgaussfilt(I2,2);
subplot(2,2,1);imshow(I);title('orginal image', 'FontSize', 10);
subplot(2,2,2);
imshow(I1);
title('1st Blur', 'FontSize', 10);
subplot(2,2,3);
imshow(I2);
title('2nd Blur', 'FontSize', 10);
subplot(2,2,4);
imshow(I3);
title('3rd Blur', 'FontSize', 10); 
[ro co]=size(I);
for r = 2 : ro - 1   
  for c = 2 : co - 1    
    centerPixel = I(ro, co);
    end
end
meanval = mean2(I);
ELBP_CI = double((centerPixel-meanval) >= 0);
R= 40;
xc=size(I)/2+.5;
yc=size(I)/2+.5;
Angles = [0, 45, 90, 135, 180, 225, 270, 315, 360] ;
x = xc(1)+R*cos(Angles*pi/180) ;
y = yc(1)+R*sin(Angles*pi/180) ;
for k = 1 : length(x)
    row = round(y(k)); 
    col = round(x(k));
    pixelvalue(k) = I(row, col);
end
 neighb_pixelsaverage=(pixelvalue(1)/9)+(pixelvalue(2)/9)+(pixelvalue(3)/9)+(pixelvalue(4)/9)+(pixelvalue(5)/9)+(pixelvalue(6)/9)+(pixelvalue(7)/9)+(pixelvalue(8)/9)+(pixelvalue(9)/9);
 ELBPNI=0;
for i=1 : length(pixelvalue)
    L=pixelvalue(i)-neighb_pixelsaverage;
    if(L>=0)
     M=1;
    end
    if (L<0)
     M=0;
    end
    ELBPNI(i)=M*(2^i);
    ELBPNI=ELBPNI+ELBPNI(i);
end
ELBP_NI=ELBPNI;
R=70;

x = xc(1)+R*cos(Angles*pi/180) ;
y = yc(1)+R*sin(Angles*pi/180) ;

for k = 1 : length(x)
    row = round(y(k));
    col = round(x(k));
    pixelvalue1(k) = I(row, col);
end

   neighb_pixelsaverage1=(pixelvalue1(1)/9)+(pixelvalue1(2)/9)+(pixelvalue1(3)/9)+(pixelvalue1(4)/9)+(pixelvalue1(5)/9)+(pixelvalue1(6)/9)+(pixelvalue1(7)/9)+(pixelvalue1(8)/9)+(pixelvalue1(9)/9);
   ELBPNI=0;
  for i=1 : length(pixelvalue)
      L=pixelvalue1(i)-neighb_pixelsaverage1;
      if(L>=0)
          M=1;
     if(L<0)
             M=0;
         end
       ELBPNI1(i)=M*(2^i);
       ELBPNI1=ELBPNI1+ELBPNI1(i);
      end
  end
  ELBP_NI1=ELBPNI1;
  for i=1 : length(pixelvalue)
      L=pixelvalue(i)-pixelvalue1(i);
      if(L>=0)
          M=1;
     if(L<0)
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 M=0;
         end
       ELBPRD(i)=M*(2^i);
       ELBPRD=ELBPRD+ELBPRD(i);
      end
  end
  ELBP_RD=ELBPRD;

Answer 2

[KSSV]

I = imread('alu foil.jpg') ;
[nx,ny,d] = size(I) ;
%%define your circle
R= 10 ; 
figure
hold on
imshow(I) ;
[xc,yc] = getpts() ;   % extract the center of circle
%
Angles = [0, 45, 90, 135, 180, 225, 270, 315, 360] ;   % location in degrees
% In polar coordinates
iwant = [R*ones(1, length(Angles)); Angles*pi/180] ;
% In cartesian coordinates
x = xc(1)+R*cos(Angles*pi/180) ;
y = yc(1)+R*sin(Angles*pi/180) ;
%
hold on
plot(x,y,'*r') ;
%%Do interpolation to get pixels 
R = uint8(interp2(1:ny,1:nx,double(I(:,:,1)),x,y)) ; % Red Channel
G = uint8(interp2(1:ny,1:nx,double(I(:,:,2)),x,y)) ; % Green Channel
B = uint8(interp2(1:ny,1:nx,double(I(:,:,3)),x,y)) ; % Blue Channel

When prompted...click at a point, where you want the circle to be. This point will be the center of circle.

[Rashmi.D Jeya kumar]

Thank you sir!! I am not geting the pixel value if R,G,B in comnd windw R=G=B (ie) same value.