i have three gray images. How to combine them and assign them to each channel of r g b?

i have three gray images of same size. suppose the name is a b c. i want to construct a pseudo rgb image where red ,green , blue channels correspond to a, b , c respectively.

[John BG]

Hi Ammol

this is John BG [e-mail]

could you supply the 3 images you have tried to combine?

If you attach the input images to your question or comment the readers can reproduce steps.

[anmol maharana]

I have three images of single type. t1, t2, flair of MRI. I want to construct a pseudo rgb image like provided in the images below.

165:

167:

[Image Analyst]

OK, fine, but you have not provided the individual gray scale images representing the 3 MRI states. You've only given us two sets of already-colored RGB images without any explanation of what color planes t1, t2, and flair went into for each of the color channels. So it might be

rgbImage = cat(3, t1, t2, flair);

or it might be

rgbImage = cat(3, flair, t2, t1);

How is any supposed to know from what you posted? Plus, what if they have vastly different ranges? Do you scale each channel before combining? Again, we have no idea.

Read this then try again.

[anmol maharana]

Sorry for the question format. I have tried to upload the image. the image size is large and cant be compressed. so i am unable to give it.it is not about the combination. i am asking you about the pseudo coloring steps. how to scale each channel? in the image provided above A=flair image, B=t1 image C=t2 image

Answer 1

[Walter Roberson]

cat(3, a, b, c)

[anmol maharana]

I have tried that but the output image i am getting is total black.is there any way to use colormap?

[Walter Roberson]

No, there is no way to use a colormap with an RGB image.

I suspect that your a b and c are type double but that they contain integer values. If so then you should probably uint8() the result of the cat(3)

[anmol maharana]

i have tried as you said and i am getting the following image.

[anmol maharana]

i want to get image like below.

[Walter Roberson]

Difficult to say without the images, but I suspect that the image you posted with the white is the proper image for your task of constructing pseudocolor images from those three greyscale planes. That is, I think you are probably trying to do the wrong thing.