how to make a light color features to become bright?

good day i have an image with extracted blood vessels and with no noise and a complete figure with all vessels in it..but some of my vessels are light in color..is there a way to make it dark.my image is..

expected output image is (this is image is a manualy drawn image form DRIVE data set

original vessels are

Answer 1

[Image Analyst]

grayImage(binaryImage) = 0; % Set white pixels to black.
grayImage(binaryImage) = 0.5 * grayImage(binaryImage); % Set white pixels to half intensity.

[vidya]

thank you sir.. can you also tell me what methods can be used to remove the cup of the above image..i want only the vessels to remain

[Image Analyst]

1. invert the image
2. call imclearborder
3. call bwconvhull
4. multiply that by your original image.

[vidya]

sir this code did not work for me ...i just get a black line as a image

grayImage(binaryImage) = 0; % Set white pixels to black.
grayImage(binaryImage) = 0.5 * grayImage(binaryImage); % Set white pixels to half intensity.

[Image Analyst]

How do you define "dark"? Does that mean black? Or just reduced intensity, like half as bright as it used to be. It you want it to be black, just use the first line, not the second.

[vidya]

sorry for not mentioning "dark" my dark means white..since my vessels are white in color and some parts of vessel are very light as in ends of vessels i want all my vessels to appear bright white...how do i do it

[Image Analyst]

Now you've confused us. Are you thinking this can all be done starting with the binary image you attached at the very top of this post? Please attach the desired output image. Also attach the original gray scale or color image if you think that would help.

[Image Analyst]

I don't have any way of making the super faint vessels get detected, but I'm pretty sure it has been done before. If you go to section 20.5 here http://iris.usc.edu/Vision-Notes/bibliography/contentsmedical.html#Medical%20Applications,%20CAT,%20MRI,%20Ultrasound,%20Heart%20Models,%20Brain%20Models you will find lots of papers on that. There are plenty of spatial filters and ridge/valley detectors that could work, and I'm sure some of the papers have algorithm specialized for fundus images.

[vidya]

Above u told me to use bwconvhull.. for d removal of cup..but i dont have .m file of bwconvhull...is there any other function that can substitute convhull