MATLAB: A beginners question to clarify something I am trying to do it MATLAB regarding an image

beginnerfunctionimage processingMATLABvariables

I am trying to learn how to use MATLAB so therefore am a complete beginner, I am sorry if this question is very basic or I do not use the correct terms/explain myself properly as I have no programming experience and I am finding it quite difficult to understand the help guide and textbook I have.
So I have created three variables for the colour bands by typing
Image_red=Image(:,:,1); Image_green=Image(:,:,2); Image_blue=Image(:,:,3);
and I can display one (eg red) by typing
figure, imagesc(Image_red), colormap(‘gray’)
The textbook I am working through then starts with the following instructions on using a variable to control the band selection.
Type >>band=1;
Then type >>Image_new=Image(:,:,band);
We will still get the red band in the new image. If we set band=2 then we would get the green band..
Write a new function called ‘draw1band.m’ which uses two input variables: an image name and another variable called ‘band’ to draw a grayscale image of either of the 3 bands. Once written, you should be able to type:
>>draw1band(‘srgmatlab’, 3)
And get a figure of the blue band.
I can't for the life of me figure out how to do this! Could anyone offer any help please? Thank you in advance. Sam

Best Answer

Hi,
Have a look at "function". type
doc function
In this case you need something like:
function [] = draw1band(inputImage,band)
%maybe sanity checks for band and inputImage
oneCh=inputImage(:,:,band);
figure
imagesc(oneCh);
colormap gray;
end
You need to save this as an .m file. You can do this in many ways. Maybe try :
edit draw1band
Feel free to have a look at the FAQ page http://matlab.wikia.com/wiki/FAQ
Regards, Florin
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