Enhance image in matlab - exp operation - imageJ software-LPR
You have to learn to debug your programs. Try formula for some data:

&gt;&gt; 255*exp(255/46.01)
  ans =   6.5091e+004


So formula has bug (explanation in link to forum is valid. Read it carefully). Valid formula:

&gt;&gt; exp(255/46.01)
 ans =  255.26


But try calculation with real data from your image:

&gt;&gt; in = (im(10,10)+1)
in = 254
&gt;&gt; exp(in/46.01)
ans =  403.43    % very strange result!!!!
&gt;&gt; in/46.01
ans = 6          %what is it????


Reason is quite simple - type of in is uint8!!!

Valid formula:

result(i,j) = exp(double(in)/46.01);


result:

imshow(uint8(result));