
I use this command:
"convert res.png -blur 0x0.5 -contrast-stretch 50x0%% -unsharp 0x2 z.png"
result is:

I don't know to how i remove background to take text. Anybody help me, please !
I use an other way:
"convert res.png -edge 1 -negate -normalize -colorspace Gray -blur 0x.5 -contrast-stretch 0x50% y.png"
Then, i have an image:

I want an image with "white background" and "black text", help me, please, please, please !