MATLAB - CODING'S

Identifying Objects based on color (RGB) 

A bitmap image with different shapes filled with primary colors Red, Blue and Green.The objects in the image are separated based on the colors. The image is a RGB image which is a 3 dimensional matrix.

Lets use (i,j) for getting the pixel position of the image A.

In the image, A (i, j, 1) represents the value of red color.

 A (i, j, 2) represents the green color.

A (i, j, 3) represents the blue color.

To separate the objects of color red:

Check if A (i, j, 1) is positive. [In most cases the value will be 255];

 A (i, j, 2) and A (i, j, 3) will be zero.

Similarly, other colors can be separated.

MATLAB CODE:

A=imread('shapes.bmp');

figure,imshow(A);

title('Original image');

%Preallocate the matrix with the size of A

Red=zeros(size(A));

Blue=zeros(size(A));

Green=zeros(size(A));

for i=1:size(A,1)

    for j=1:size(A,2)

       

        %The Objects with Red color

        if(A(i,j,1) < = 0)

          Red(i,j,1)=A(i,j,1);

          Red(i,j,2)=A(i,j,2);

          Red(i,j,3)=A(i,j,3);

        end

       

        %The Objects with Green color

        if(A(i,j,2) < = 0)

          Green(i,j,1)=A(i,j,1);

          Green(i,j,2)=A(i,j,2);

          Green(i,j,3)=A(i,j,3);

        end

       

        %The Objects with Blue color

        if(A(i,j,3) < = 0)

          Blue(i,j,1)=A(i,j,1);

          Blue(i,j,2)=A(i,j,2);

          Blue(i,j,3)=A(i,j,3);

        end

       

    end

end

Red=uint8(Red);

figure,imshow(Red);

title('Red color objects');

            

Blue=uint8(Blue);

figure,imshow(Blue);

title('Blue color objects');

             

                 

Green=uint8(Green);

figure,imshow(Green);

title('Green color objects');

Identifying the objects based on count(bwlabel) 

Steps To Be Performed:

1. Convert the RGB image to binary image.
2. Fill the holes in the image.
3. Label the objects in the image based on connectivity 8
4. Display the images in a RGB format

4.1.  Store the co-ordinates(x,y) of the object 1 which is  labeled as 1.

4.2.  Calculate the image size for object one. The length can be found by subtracting the maximum and the minimum of y values. Similary for x find the width by subtracting the maximum and minimum of x values.

4.3.  Now map the pixel value to the new image.

A=imread('num2.jpg');

figure,imshow(A);

title('Original image');

C=~im2bw(A);

B=imfill(C,'holes');

label=bwlabel(B,8);

for j=1:max(max(label))

[row, col] = find(label==j);

len=max(row)-min(row)+2;

breadth=max(col)-min(col)+2;

target=uint8(zeros([len breadth 3] ));

sy=min(col)-1;

sx=min(row)-1;

for i=1:size(row,1)

    x=row(i,1)-sx;

    y=col(i,1)-sy;

    target(x,y,:)=A(row(i,1),col(i,1),:);

end

mytitle=strcat('Object Number:',num2str(j));

figure,imshow(target);title(mytitle);

end

The objects that are displayed in a RGB format.