How can I make one side of a color image greyscale and then have the color gradually return to the other?

I have a color image that I want to process in a very specific way. I need a code that can convert far lefthand side of the picture to the equivalent grey (so still in rgb format), and then have the color gradually return as you go right. I would also like to be able to set the point where the picture is completely restored.

Same question for the noise. Could I add some noise (make the picture grainy) in the same way - left side very noisy, then gradually the noise disappears until some point where it disappears completely?

Thank you all in advance.

Answer 1

[Image Analyst]

In the hsv color space you could just multiply your saturation image by values going from 1 down to 0 to reduce the image to gray.

hsv = rgb2hsv(rgbImage);
hsv(:,:,2) = hsv(:,:,2)*reductionFactor;
newrgbImage = hsv2rgb(hsv);

or something similar. For the noise, just add different amounts of noise with imnoise. Not hard. Write back if you can't figure it out.