Try please 
SCAR Code:
program New;
var
MapCan1, MapCan2, MapCan3: TCanvas;
MapBmp1, MapBmp2, MapBmp3: Integer;
MX1, MY1, MX2, MY2, x, y: Integer;
procedure Setup;
begin
MX1 := 520;
MY1 := 0;
MX2 := 765;
MY2 := 175;
MapBmp1 := BitmapFromString(245, 175, ' ');
MapBmp2 := BitmapFromString(245, 175, ' ');
MapBmp3 := BitmapFromString(245, 175, ' ');
end;
procedure GetMapCans;
begin
CopyClientToBitmap(MapBmp1, MMX1, MMY1, MMX2, MMY2);
MapCan1 := GetBitmapCanvas(MapBmp1);
Wait(2000);
CopyClientToBitmap(MapBmp2, MMX1, MMY1, MMX2, MMY2);
MapCan2 := GetBitmapCanvas(MapBmp2);
Wait(2000);
end;
procedure TakeOutMatches;
begin
MapCan3 := MapCan1;
for x := 0 to 245 do
for y := 0 to 175 do
begin
if (MapCan1.Pixels[x, y] <> MapCan2.Pixels[x, y]) then
MapCan3.Pixels[x, y] := 255;
end;
DisplayDebugImgWindow(245, 175);
CopyCanvas(MapCan3, GetDebugCanvas, 0, 0, 245, 175, 0, 0, 245, 175);
end;
begin
Setup;
GetMapCans;
TakeOutMatches;
end.