combining RGB to get a full image

image_RGB = cat(2,final_red,final_green,final_blue)

imshow(image_RGB);

can anyone suggest me that this code is correct for combining RGB components for getting full image

as soon as possible

Answer 1

[Image Analyst]

IMPORTANT NOTE: MATLAB is case sensitive. redchannel is different than redChannel.

It looks like you've taken code I've posted many times and tried to adapt it:

% Extract the individual red, green, and blue color channels.
redChannel = rgbImage(:, :, 1);
greenChannel = rgbImage(:, :, 2);
blueChannel = rgbImage(:, :, 3);

% Recombine separate color channels into an RGB image.
rgbImage = cat(3, redChannel, greenChannel, blueChannel);

I call them "channels" because that is the terminology Photoshop uses. You have to change the name of the arrays from redChannel to what yours are called. After you split apart your color channels and reprocessed them you have final_red. This, NOT redChannel, is what you need to use. You also need to not change from dimension 3 (which I had) to dimension 2. So the final code would be

    % Recombine separate color channels into an RGB image.
    rgbImage = cat(3, final_red,final_green,final_blue);

[prem preet]

thanks sir ,

i gonna try this..

[Shaila parvin]

rgbImage = cat(3, final_red,final_green,final_blue);

What will happen if I write 2/1/4/something else in place of 3. I mean:

rgbImage = cat(1, final_red,final_green,final_blue);

[Titus Edelhofer]

It will most likely fail: the 3 is denoting the 3rd dimension. For RGB images: 1. and 2. dimension give the size in pixels, the 3. dimension is the color.

[surendra gupta]

Sir, I have RGB values. Now I want a color image (single color) to display. Please let me know how to do it.

Actually, I have several RGB values in the form of two-dimensional matrix, so I want to represent all of them in single plot. Please help me with the required snippet.

[Image Analyst]

imshow(rgbImage);

[Guillaume]

@surendra gupta,

Please don't spam the forum. You've already asked that question. Until you give better explanations of what you want to achieve and what you start with, you'll only be given similar answers to use imshow, image, imagesc or pcolor.

[Chrissie Nyssen]

It's a 3D image if you are layering the R G B images on top of each other -

imgRGB = cat(3, R, G, B)

imshow (imgRGB)

[Srivatsan N]

Is there any way to transform the grayscale image to rgb image?

Answer 2

[Wayne King]

Hi, You don't want to concatenate along the column dimension. An RGB image has 3 dimensions. You want to concatenate along the 3rd dimension.

      imdata = imread('ngc6543a.jpg');
      RC = imdata(:,:,1);
      GC = imdata(:,:,2);
      BC = imdata(:,:,3);
      im = cat(3,RC,GC,BC);
      isequal(imdata,im)
      imshow(im)

[prem preet]

sir i find some errors on my matlab 2008 but on matlab 2010 it doesnt show any error can u suggest me something..

[prem preet]

for example this sir

redChannel = noisy_picture(:, :, 1);

greenChannel = noisy_picture(:, :, 2);

blueChannel = noisy_picture(:, :, 3);

it shows undefined symbol when i try imshow function for each

[Wayne King]

please post the exact error message

[prem preet]

??? Undefined function or variable 'redchannel'.

[prem preet]

this error occured for all 3 above functions ....

imshow(redchannel);.....

plss rply fast..

Answer 3

[tablo tofiq]

display image in three color red&green&blue

a=imread('autumn.tif');
a1=a;
a1(:,:,2)=0;
a1(:,:,3)=0;
subplot(3,1,1)
imshow(a1)
a2=a;
a2(:,:,1)=0;
a2(:,:,3)=0;
subplot(3,1,2)
imshow(a2)
a3=a;
a3(:,:,1)=0;
a3(:,:,2)=0;
subplot(3,1,3)
imshow(a3)

[Stephen23]

Without three intermediate variables:

b = imread('autumn.tif');
b(:,:,4) = 0;
subplot(3,1,1)
imshow(b(:,:,[1,4,4]))
subplot(3,1,2)
imshow(b(:,:,[4,2,4]))
subplot(3,1,3)
imshow(b(:,:,[4,4,3]))