How to Enhance this finger print? I am trying to extract finger print from this image by using green LED backlight but when it convert to binarize image most of finger print is gone.

gray= green


I use this fomular to convert from this color image

 

to this gray image



I use otsu for binarization. So Which preprocessing I should use before convert to binarization to emphasis the finger print.
Two steps,


do a simple histogram equalization to make the brightness a little
bit more even.
Then use canny edge detector (as suggested by Marcus Muller).


matlab code:

I=imread('Your Image');
G1=rgb2gray(I);
G2=histeq(G1);
E2=edge(G2,'canny'); 
figure imshow(E2,[]);


Result (I hope it is what your are looking for):