How to generate image matrix Red Green Blue Yellow Green

Generate the following image by defining image matrix:

Red Green Blue Yellow Green.

B(1:100,1:100,1:100,1:00,1:3)=0;
 imshow (B)
B(1:50,1:50,1) =1;
B(51:100,51:100,2)=1;
imshow(B)

I am trying to get a 3x3 with the specified colors; Red Green Blue Yellow Green. It's not working, it gives error.

Answer 1

[Image Analyst]

Is this what you're looking for:

redChannel = zeros(100, 100, 'uint8');
greenChannel = zeros(100, 100, 'uint8');
blueChannel = zeros(100, 100, 'uint8');
redChannel(1:50,:) = 255;
greenChannel(:, 1:50) = 255;
blueChannel(51:100, 51:100) = 255;
coloredImage = cat(3, redChannel, greenChannel, blueChannel);
imshow(coloredImage)

[Jjet Jumbo]

Yes, it is...but how do I complete this method using this codes also? Pls if you can also explain how it works. Thank you!

B(1:100,1:100,1:3)=0; imshow(B) B(1:50, 1:50, 1) = 1; imshow(B) B(51:100,51:100,2) =2; imshow(B)

[Image Analyst]

You need to use 255, not 1 or 2 which will be so dark you can't see it. Also, make sure they're uint8, not double.

[Jjet Jumbo]

ok, thanks..just that it's the way we are being thought in the class. So confusing. I clearly understood yours.

[Walter Roberson]

If you are going to use 0, 1, 2, then use a 2 dimensional matrix rather than a 3D matrix, and fill each location with a number indicating the color number that should go there (like paint-by-numbers.) Then after imshow(), use colormap() to put in place a colormap you created that maps between the color number and the RGB value that should be associated with that color.

[Cesar]

Can you please complete it to create the 3 X 3 image:

Red    Yellow
  Green  
Green    Blue

[Image Analyst]

Cesar, you can see my solution and the modifications to it to do what you want should be straightforward. Just change the row and column ranges.

Answer 2

[Walter Roberson]

B(1:100,1:100,1:100,1:00,1:3)=0 tries to define a 5 dimensional array in which the fourth dimension is empty. 1:00 is empty. Perhaps you meant 1:100 .

RGB matrices are 3 dimensional.

You may wish to use zeros() to initialize the matrix.