Change Pixel intensity value

Hi all,

I have an image(gray scale) whose pixel intensity values ranges from -0.5373 to 0.4744. I would like to change the intensity value which is lesser than 0 to 0. Can any one help me to solve this.

Thanks.

Answer 1

[Honglei Chen]

Say your image is x,

x(x<0) = 0;

[Pugazhendhi]

thanks for the quick reply. Its working and one more help how i can do it for RGB images.

thanks in advance.

[Honglei Chen]

RGB image has 3 pages, so you need to do this for each page. If operation is the same, you can reshape it, do the conversion, and reshape back. For example

x = rand([3 3 3])-0.5;

x = reshape(x,3,[])

x(x<0)=0

reshape(x,3,[],3)

[Pugazhendhi]

thanks, Can you explain the role of 0.5 here.

[Honglei Chen]

I'm just making an example, make sure there are negative numbers in x.

[Image Analyst]

No, you don't need all that reshaping stuff. "x(x<0)=0" is sufficient to work on the whole 3D matrix (e.g., a color image) - no reshaping is needed.

Answer 2

[Walter Roberson]

X = max(0, X);     %another way of changing anything less than 0 to 0

[Pugazhendhi]

Thanks for the help

Answer 3

[vishnu lohith]

use a suitable transformation to change the intensities from ( 0,255) to (65,180).

[Image Analyst]

Are you sure you posted to the correct six year old question? Not sure what your answer has to do with the original question about clamping the signal to zero.