bmp.assign(image1.Picture .Bitmap);
bmp.PixelFormat :=pf24bit;
randomize;
for y:=0 to bmp.height-1 do
begin
 p:=bmp.ScanLine [y];
 for x:= 0 to bmp.width-1 do
 begin
  gray:=round(p[x*3]*0.3 p[x*3 1]*0.59 p[x*3 2]*0.11);
  if gray>z then
   begin
   p[x*3]:=0;
   p[x*3 1]:=0;
   p[x*3 2]:=0;
   end
   else
   begin
   p[x*3]:=255;
   p[x*3 1]:=255;
   p[x*3 2]:=255;
   end;
   end;
   end;
   image2.picture.Bitmap.Assign(bmp);
   bmp.Free; 
end;