Need help improving my Code.

I$\text{'}$m suppose to improve the image using filtering and remove as much of the pattern without degrading the image as possible.

I remove the pattern but the image is coming out dark

Here's my function code:

function g $=$ ImageFitering$($f$)$

$\%$ Convert image to double precision for processing

f $=$ im$2$double$($f$)$;

$\%$ Compute Fourier transform of the image

F $=$ fft$2($f$)$;

$\%$ Shift the zero frequency component to the center

F$\_$shifted $=$ fftshift$($F$)$;

$\%$ Define a mask to filter out high$-$frequency components $($where pattern is present$)$

$[$rows$,$ cols$]=$ size$($F$)$;

mask $=$ ones$($rows$,$ cols$)$;

radius $=37$; $\%$ Adjust this value based on the size of the pattern in frequency domain

center $=[$rows$/2+1,$ cols$/2+1]$;

$[$X$,$ Y$]=$ meshgrid$(1$:cols, $1$:rows$)$;

distance $=$ sqrt$(($X $-$ center$(2)).^2+($Y $-$ center$(1)).^2)$;

mask$($distance radius$)=0$; $\%$ Low$-$pass filter to retain low$-$frequency components

$\%$ Apply the mask to the shifted Fourier transform

F$\_$filtered $=$ F$\_$shifted $.*$ mask;

$\%$ Shift the zero frequency component back to the corner

F$\_$unshifted $=$ ifftshift$($F$\_$filtered$)$;

$\%$ Compute the inverse Fourier transform to get the filtered image

g $=$ real$($ifft$2($F$\_$unshifted$))$;

$\%$ Clip values to ensure they are in the range $[0,1]$

g $=$ min$($max$($g$,0),1)$;

$\%$ Perform automatic scaling to adjust brightness

g $=($g $-$ min$($g$($:$)))/($max$($g$($:$))-$ min$($g$($:$)))$;

end